Journal articles on the topic 'Ley pasture legumes'
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1
Singh, D. K., N. McGuckian, R. A. Routley, G. A. Thomas, R. C. Dalal, Y. P. Dang, T. J. Hall, et al. "Poor adoption of ley-pastures in south-west Queensland: biophysical, economic and social constraints." Animal Production Science 49, no. 10 (2009): 894. http://dx.doi.org/10.1071/an09015.
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The present review identifies various constraints relating to poor adoption of ley-pastures in south-west Queensland, and suggests changes in research, development and extension efforts for improved adoption. The constraints include biophysical, economic and social constraints. In terms of biophysical constraints, first, shallower soil profiles with subsoil constraints (salt and sodicity), unpredictable rainfall, drier conditions with higher soil temperature and evaporative demand in summer, and frost and subzero temperature in winter, frequently result in a failure of established, or establishing, pastures. Second, there are limited options for legumes in a ley-pasture, with the legumes currently being mostly winter-active legumes such as lucerne and medics. Winter-active legumes are ineffective in improving soil conditions in a region with summer-dominant rainfall. Third, most grain growers are reluctant to include grasses in their ley-pasture mix, which can be uneconomical for various reasons, including nitrogen immobilisation, carryover of cereal diseases and depressed yields of the following cereal crops. Fourth, a severe depletion of soil water following perennial ley-pastures (grass + legumes or lucerne) can reduce the yields of subsequent crops for several seasons, and the practice of longer fallows to increase soil water storage may be uneconomical and damaging to the environment. Economic assessments of integrating medium- to long-term ley-pastures into cropping regions are generally less attractive because of reduced capital flow, increased capital investment, economic loss associated with establishment and termination phases of ley-pastures, and lost opportunities for cropping in a favourable season. Income from livestock on ley-pastures and soil productivity gains to subsequent crops in rotation may not be comparable to cropping when grain prices are high. However, the economic benefits of ley-pastures may be underestimated, because of unaccounted environmental benefits such as enhanced water use, and reduced soil erosion from summer-dominant rainfall, and therefore, this requires further investigation. In terms of social constraints, the risk of poor and unreliable establishment and persistence, uncertainties in economic and environmental benefits, the complicated process of changing from crop to ley-pastures and vice versa, and the additional labour and management requirements of livestock, present growers socially unattractive and complex decision-making processes for considering adoption of an existing medium- to long-term ley-pasture technology. It is essential that research, development and extension efforts should consider that new ley-pasture options, such as incorporation of a short-term summer forage legume, need to be less risky in establishment, productive in a region with prevailing biophysical constraints, economically viable, less complex and highly flexible in the change-over processes, and socially attractive to growers for adoption in south-west Queensland.
2
Cameron, AG. "Evaluation of tropical pasture species as leys in the semi-arid tropics of northern Australia." Australian Journal of Experimental Agriculture 36, no. 8 (1996): 929. http://dx.doi.org/10.1071/ea9960929.
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Testing of pasture plants as leys in the semiarid tropics of northern Australia has been limited. Characteristics of successful ley pasture plants are discussed. The most important characteristic is the ability to contribute nitrogen to subsequent crops, which has been demonstrated for a number of legumes but not for grasses. Over 2300 legume and grass introductions have been evaluated as permanent pastures. Of the genera which are adapted to the environment of northern Australia, 14 grass cultivars (including Brachiaria, Cenchrus and Digitaria spp.) and 11 legume cultivars (including Aeschynomene, Centrosema and Stylosanthes spp.) are productive and are currently recommended for use as permanent pasture plants. Field experiments and commercial practice have shown that Centrosema pascuorum (cvv. Bundey, Cavalcade) is well adapted for use as a ley pasture plant. Other legumes which are suitable for use in leys are Alysicarpus vaginalis, Chamaecrista rotundifolia cv. Wynn, Macroptilium gracile cv. Maldonado and Stylosanthes hamata cvv. Amiga and Verano. The grasses are generally not suitable for ley pastures as they are strong perennials which are difficult to control in cropping areas. The exception is Urochloa mosambicensis which may be suitable as a break crop to control broadleaf weeds such as Sida acuta, Senna obtusifolia and Hyptis suaveolens. This species can be controlled with economic rates of herbicide and has seed dormancy characteristics which allow it to regenerate following a cropping phase.
3
Whitbread, A. M., and R. L. Clem. "Graze to grain—measuring and modelling the effects of grazed pasture leys on soil nitrogen and sorghum yield on a Vertosol soil in the Australian subtropics." Australian Journal of Agricultural Research 57, no. 5 (2006): 489. http://dx.doi.org/10.1071/ar05189.
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Highly productive sown pasture systems can result in high growth rates of beef cattle and lead to increases in soil nitrogen and the production of subsequent crops. The nitrogen dynamics and growth of grain sorghum following grazed annual legume leys or a grass pasture were investigated in a no-till system in the South Burnett district of Queensland. Two years of the tropical legumes Macrotyloma daltonii and Vigna trilobata (both self regenerating annual legumes) and Lablab purpureus (a resown annual legume) resulted in soil nitrate N (0–0.9 m depth), at sorghum sowing, ranging from 35 to 86 kg/ha compared with 4 kg/ha after pure grass pastures. Average grain sorghum production in the 4 cropping seasons following the grazed legume leys ranged from 2651 to 4012 kg/ha. Following the grass pasture, grain sorghum production in the first and second year was <1900 kg/ha and by the third year grain yield was comparable to the legume systems. Simulation studies utilising the farming systems model APSIM indicated that the soil N and water dynamics following 2-year ley phases could be closely represented over 4 years and the prediction of sorghum growth during this time was reasonable. In simulated unfertilised sorghum crops grown from 1954 to 2004, grain yield did not exceed 1500 kg/ha in 50% of seasons following a grass pasture, while following 2-year legume leys, grain exceeded 3000 kg/ha in 80% of seasons. It was concluded that mixed farming systems that utilise short term legume-based pastures for beef production in rotation with crop production enterprises can be highly productive.
4
Loi, A., J. G. Howieson, B. J. Nutt, and S. J. Carr. "A second generation of annual pasture legumes and their potential for inclusion in Mediterranean-type farming systems." Australian Journal of Experimental Agriculture 45, no. 3 (2005): 289. http://dx.doi.org/10.1071/ea03134.
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A second generation of annual pasture legumes and their root-nodule bacteria has been released to agriculture in Mediterranean-type environments. These new species emanate from selection activity focussed upon ‘alternative legumes’. In 1992, in response to changing constraints upon production, a program was initiated which sought species with different ideotypic traits to the traditional annual medics and clovers used in agriculture in southern Australia. Traits sought in the new species were deeper root systems, improved persistence from higher hardseed levels, acid tolerant symbioses, tolerance to pests and diseases and ease of harvesting with conventional cereal harvesters. Several cultivars of species new to Australian agriculture such as biserrula (Biserrula pelecinus), French serradella (Ornithopus sativus), gland clover (Trifolium glanduliferum) and improved varieties of arrowleaf clover (Trifolium vesiculosum) and yellow serradella (Ornithopus compressus) were developed and have had rapid adoption and impact in southern Australian ley- and phase-farming systems. This paper reviews the importance of ley farming for Australian agriculture, the shortcomings of the traditional medics and clovers and the imperatives for a second generation of annual pasture legume species to be developed. In addition to enhancing ley farming, the commercial availability of a second generation of annual pasture legume species has provided a much needed impetus for the development of more flexible and sustainable farming systems.
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Clem, RL, and TJ Hall. "Persistence and productivity of tropical pasture legumes on three cracking clay soils (Vertisols) in north-eastern Queensland." Australian Journal of Experimental Agriculture 34, no. 2 (1994): 161. http://dx.doi.org/10.1071/ea9940161.
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There are few commercial legumes available for sowing on the cracking clay soils of northeastern Queensland, where legumes are needed to improve quality of perennial native grass pastures and to arrest nitrogen decline in cropping land. To evaluate introduced legumes from heavy-textured soils, a replicated row experiment was established in 3 environments to assess the adaptation of 56 accessions from 37 species (22 genera). The sites were on 3 dark cracking clay soils supporting the following grasslands: Dichanthium -Bothriochloa- Astrebla; Dichanthium aristatum; and Cenchrus ciliaris on cleared Acacia harpophylla (brigalow) country.The main selection criteria during the 4-year evaluation were persistence, regeneration, production, and spread, with green leaf retention, nutrient concentrations, and pest susceptibility also being considered. The perennial legumes Clitoria ternatea (CPI 47 187 and CPI 49963), Desmanthus virgatus (CPI 78373), Leucaena leucocephala (CPI 61227 and cv. Cunningham), Stylosanthes scabra (CPI 55868), and Indigofera schimperi (CPI 69495), and annuals Centrosema pascuorum (CPI 55697), Desmodium dichotomum (CPI 47 186), and Vigna trilobata (CPI 47510), showed promise as pasture or short-term ley species for these clay soils (Vertisols) in subcoastal, north-eastern Queensland. Other species were identified that require evaluation of a wider range of genetic material. The role of perennial and annual sown legumes in pasture and cropping systems on these cracking clay soils is discussed.
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Hossain, SA, SA Waring, WM Strong, RC Dalal, and EJ Weston. "Estimates of nitrogen fixations by legumes in alternate cropping systems at Warra, Queensland, using enriched - 15N dilution and natural 15N abundance techniques." Australian Journal of Agricultural Research 46, no. 3 (1995): 493. http://dx.doi.org/10.1071/ar9950493.
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Nitrogen fixation was measured using two isotopic techniques over 2 years as part of a long-term field experiment established to test alternative management strategies for restoring fertility in a vertisol at Warra, Southern Queensland. Treatments containing legumes were: grass- legume ley (purple pigeon grass and Rhodes grass, lucerne and annual medics) for 4 years followed by 4 years of wheat; a 2-year rotation of lucerne and wheat; a 2-year rotation of medic and wheat; and a 2-year rotation of chickpea and wheat. For the enriched-15N procedure, the proportion of N derived from air (% Ndfa) for the grass-legume and lucerne and medic leys ranged from 67 to 97%, and averaged 85%, with little evidence for effects of season, pasture establishment, time or species. The % Ndfa for chickpea was significantly lower (62%). Values for the natural abundance 15N procedure were mostly lower and more variable than for the enriched method, ranging from 62 to 91% for the grass-legume, lucerne and medic leys, and averaged 76%. It was concluded that the enriched procedure provided more reliable estimates of N2 fixed by the legumes. N2 fixation measured by the enriched-15N dilution method in the grass-legume ley averaged 80 kg N ha-1 during 2 years. A similar amount of N was fixed by the lucerne ley during 1 year (83 kg N ha-1 but medic ley fixed less (56 kg N ha-1 The amount of N2 fixed by chickpea was 72 kg N ha-lyear-1. The dry matter yield of the legumes in leys, mainly lucerne, was closely associated with the amount of N2 fixed, with a value of 28 kg of N2 fixed for each tonne of dry matter produced.
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McDonald, GK. "The contribution of nitrogen fertiliser to the nitrogen nutrition of rainfed wheat crops in Australia: a review." Australian Journal of Experimental Agriculture 29, no. 3 (1989): 455. http://dx.doi.org/10.1071/ea9890455.
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Very little nitrogen (N) fertiliser is applied to wheat crops in Australia. Currently, about 105 t of N fertiliser (less than 20% of Australia's total consumption) are used annually at an average rate of 2-3 kg Nha. This scant use of N fertiliser over much of the Australian wheat belt N is because the N derived from a legume-dominant pasture ley is thought to provide a wheat crop's N requirement. However, trends in the grain protein content of Australian wheat and some other indices of soil fertility suggest that legume-based pastures have not always been able to supply all the N required for adequate nutrition of the wheat crop and that there has been some occasional need for extra N from applications of fertiliser. Recent declines in the productivity and quality of pastures has further increased the need for supplementary applications of N fertiliser. The increase in grain legume production also has been partly based on the presumption that grain legumes contribute to the N economy of the following wheat crop. Many experiments throughout the wheat belt show a yield advantage of wheat grown after a grain legume, but these rotation trials also show that the level of productivity of the grain legume has little effect on the yield of the following wheat crop. A review of these experiments suggests that grain legumes, directly, contribute little to the N nutrition of a following wheat crop and their benefit may be from the legume acting as a disease break or providing the opportunity to control grassy weeds.
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Carberry, PS, RL McCown, RC Muchow, JP Dimes, ME Probert, PL Poulton, and NP Dalgliesh. "Simulation of a legume ley farming system in northern Australia using the Agricultural Production Systems Simulator." Australian Journal of Experimental Agriculture 36, no. 8 (1996): 1037. http://dx.doi.org/10.1071/ea9961037.
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An innovative ley farming system, involving cereal crops grown in rotation with pasture legumes, has been tentatively adopted by farmers in the semi-arid tropics of northern Australia. Yet, after more than a decade of experimental research, the long-term
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Martin, CC. "Weed control in tropical ley farming systems: a review." Australian Journal of Experimental Agriculture 36, no. 8 (1996): 1013. http://dx.doi.org/10.1071/ea9961013.
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The first sustained effort to develop a ley farming system (a pasture legume rotated with a grain crop) for the Australian semi-arid tropics began in the late 1970s at Katherine, Northern Territory, where various strategies were identified and implemented. It was soon discovered that a main constraint to success was the invasion of the legume ley by grass weeds. This occurred despite the replacement of Townsville stylo (Stylosanthes humilis), which provided the base for the early work, with more competitive legumes such as Verano (Stylosanthes hamata) and Centurion centro (Centrosema pascuorum). Early weed control work focused on the use of chemicals, but later competition and population dynamics were studied in S. humilis pastures. The ley farming system comprised a number of essential elements, each of which offered opportunities for weed control First, a legume ley was rotated with grain crops. Past work concentrated on legume leys, but nitrogen (N)-fertilised grass leys may be successful if the N was economically supplied. Grasses can effectively suppress weeds. Rotation of herbicides is possible. Sicklepod (Senna obtusifolia) can be controlled with atrazine in the sorghum phase, and emergent Sida spp. can be controlled in the pasture phase using a herbicide roller. Second, cattle graze the legume ley and crop residues in the dry season. Cattle can be used to suppress grass weeds in the wet season. The major use of the legume ley, however, was to provide high quality food in the dry season when there was little other available food. Future research should investigate the economics of balancing the need for grass weed control with food provision in the dry season. Third, crops sown directly into a ley killed with a knockdown herbicide. Although the need for improved soil surface management was recognised early, development of reduced tillage was delayed until the availability of glyphosate. Initial work concentrated on improving plant establishment under mulch. Recent work has shown that mulches can effectively control weeds in crops without the use of herbicides; best weed control occurred when glyphosate was applied as a single application at sowing. Fourth, ley regenerated as an intercrop in the grain crop. There is no doubt that the presence of an intercrop reduces the yield of the grain crop. Future research should investigate the economics and risks associated with intercrop-induced changes in yield and herbicide use patterns. The extreme climate and sandy soils pose problems for herbicide use. There is marked seasonal variation in effectiveness of pre-emergence herbicides, ranging from zero to marked crop phytotoxicity. The effectiveness of knockdown herbicides is reduced by stressed target plants and rain soon after spraying. Mulch dynamics, grazing, competition and interference, and herbicide interactions with target plants and the environment, were identified as key features requiring attention in a ley farming system to achieve practical weed management.
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McCown, RL. "Being realistic about no-tillage, legume ley farming for the Australian semi-arid tropics." Australian Journal of Experimental Agriculture 36, no. 8 (1996): 1069. http://dx.doi.org/10.1071/ea9961069.
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There is a long tradition of expectation that, in time, land use in the better-endowed areas of Australia's semi-arid tropics would intensify from beef production on grassy woodlands to broadacre production of dryland crops. However, successive development attempts have yet to result in a substantial field crop industry. This paper reflects on a recent 20-year research and development episode in which ley farming, so successful in the wheat-sheep zone of southern Australia, was adapted and trialed in the tropical north. The system tested in the tropics was one which featured (i) coarse grain crops in rotation with legume leys and (ii) cattle grazing native pasture in the crop growing season and ley and crop residues in the dry season. It can be concluded that this system is technically successful. But compared with the ley system in southern Australia, the benefits of pasture legumes are less efficiently captured, both in the animal and the crop production enterprises. In addition, in this climate and on these soils, pastures with the high legume composition needed to substantially substitute for nitrogen fertiliser in the crop phase pose a serious threat of soil acidification. In contrast to legume leys, the advantage of no-tillage, mulch farming practices over conventional cultivation is much greater in this semi-arid tropical region than in temperate or Mediterranean areas: by slowing evaporation, mulch is often crucial in reducing high temperature injury or impedance to emerging seedlings as well as reducing the deleterious effects of intensive summer rainfall. But even with this improvement the climatic risks in dryland grain cropping remain a strong deterrent to crop industry development. Today, the findings from past experimentation, accrued farming experience, and new information products combine to provide what seem to be more realistic expectations for agriculture in this region. Even with the 'best' technology, this region suffers comparative disadvantage with respect to dryland field crop production and marketing. However, the region enjoys comparative advantages in the production of several other types of commodities, and a more realistic approach to 'Research and Development' includes a shift of resources toward activities with production and marketing advantages.
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Armstrong, R. D., K. McCosker, K. Walsh, G. Millar, B. Kuskopf, M. E. Probert, S. Johnson, and J. Standley. "Legume and opportunity cropping systems in central Queensland. 2. Effect of legumes on following crops." Australian Journal of Agricultural Research 50, no. 6 (1999): 925. http://dx.doi.org/10.1071/ar98101.
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Poor yields and low grain protein in cereal crops resulting from declining soil fertility, especially nitrogen (N), are major threats to the grains industry in central Queensland. The effect of 4 different pasture-ley legumes [siratro (Macroptilium atropurpureum cv. Siratro), lucerne (Medicago sativa cv. Trifecta), lablab (Lablab purpureus cv. Highworth), and desmanthus (Desmanthus virgatus cv. Marc)] on grain yield and quality of sorghum crops was compared with that of a pulse (mungbean; Vigna radiata cv. Satin) or continuous cropping with grain sorghum (Sorghum bicolor). Legume leys consistently resulted in large increases in grain yield (188–272%), N uptake by sorghum (145–345%), and grain protein (0.21–7.0% increase in grain protein) in sorghum test-crops compared with continuous sorghum crops to which no fertiliser N had been added. The positive effect of legumes persisted up to 3 sorghum test-crops after only 1 year of legumes, although by the third year the effect was comparatively small. Mungbean and lablab generally produced the largest benefit in sorghum test-crops in the first year after legumes, whereas desmanthus and lucerne produced the least benefit. Adding fertiliser N (up to 75 kg N/ha) significantly improved grain yields and N uptake of sorghum test-crops in 3 of 4 years. However, responses to fertilisers were less than those resulting from legumes, which was ascribed to increased availability of legume N to sorghum. Legumes progressively increased soil nitrate in all subsequent sorghum test-crops (compared with continuous sorghum crops), rising from 6.8–18.9 kg NO3-N/ha after 1 year of legumes to 24.2–59.6 kg NO3-N/ha after 3 years of legumes. There was little difference between the legumes in their ability to increase soil nitrate, with the exception of desmanthus, which consistently resulted in the lowest amount of soil nitrate for subsequent test-crops and lowest uptake of N by these crops. Plant-available water content (PAWC) at planting of the sorghum test-crop was only significantly (P<0.05) affected by previous species in 1997, when it was lowest in plots previously sown to siratro and lucerne and highest in sorghum and mungbean plots. In both 1996 and 1997, plots sown to sorghum had significantly higher PAWC at anthesis and grain maturity when previous plots were sorghum rather than legumes.
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Armstrong, R. D., K. Walsh, K. J. McCosker, G. R. Millar, M. E. Probert, and S. Johnson. "Improved nitrogen supply to cereals in Central Queensland following short legume leys." Australian Journal of Experimental Agriculture 37, no. 3 (1997): 359. http://dx.doi.org/10.1071/ea96129.
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Summary. The growth and ability of 12 summer-growing annual and perennial legumes to fix nitrogen and the response of a subsequent wheat crop was examined in a field trial on a deep cracking clay soil in the Central Highlands of Queensland. Twelve legumes [Lablab purpureus cv. Highworth, Vigna radiata cv. Satin, Macroptilium atropurpureum cv. Siratro, Medicago sativa cv. Trifecta, Vigna trilobata (CPI 13671), Macroptilium bracteatum (CPI 27404), Glycine latifolia (CQ 3368), Desmanthus virgatus cv. Marc, Desmanthus virgatus cv. Bayamo, Stylosanthes sp. aff scabra (104710), Clitoria ternatea cv. Milgarra, Cajanus cajan cv. Quest)] and grain sorghum (Sorghum bicolor cv. Tulloch) as a non-legume control were established in November 1994 and their growth monitored until March 1995. The legumes averaged greater than 5 t/ha dry matter production and 77 kg N/ha (above-ground only). Dry matter production ranged from less than 2 t/ha for G. latifolia and M. sativa to greater than 9 t/ha for D. virgatus cv. Bayamo and C. cajan. Annual legumes initially had much higher relative growth rates than the perennial legumes but they rapidily exhausted all the plant available water content of the soil thus allowing the well-established perennials to eventually match this production. The proportion of plant nitrogen (above ground) derived from N2 fixation was generally low, reflecting high soil NO3, but varied widely between species ranging from less than 20% for D. virgatus cv. Marc and G. latifolia to over 45% for C. ternatea, S. scabra and V. trilobata. The quantity of nitrogen derived from fixation was correlated with above-ground dry matter and nitrogen content. There was a significant (P<0.05) growth response by wheat following legumes compared with that following sorghum in the increasing order V. radiata = M. atropurpureum = L. purpureus > C. cajan = M. sativa = V. trilobata = M. bracteatum = G. latifolia > S. scabra = D. virgatus = C. ternatea. Previous legume growth had no significant (P>0.05) effect on yield or nitrogen concentration in a second ‘plant-back’ crop (sorghum). It was concluded that a wide range of pasture-ley legumes have the potential to improve cereal crop production in this region.
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Conning, S. A., M. Renton, M. H. Ryan, and P. G. H. Nichols. "Biserrula and subterranean clover can co-exist during the vegetative phase but are out-competed by capeweed." Crop and Pasture Science 62, no. 3 (2011): 236. http://dx.doi.org/10.1071/cp10218.
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Biserrula (Biserrula pelecinus L.) is a recently domesticated annual pasture legume developed for ley farming systems that have traditionally relied upon subterranean clover (Trifolium subterraneum L.). This study examined competitive interactions between biserrula and subterranean clover and the common broad-leaf weed capeweed (Arctotheca calendula L.) during seedling establishment and vegetative growth, in order to develop guidelines for successful legume pasture management. Two glasshouse experiments were conducted to investigate the allocation of biomass to roots and shoots in biserrula, capeweed, and subterranean clover and its relationship with competitive ability in the first 100 days after sowing. In Experiment 1, capeweed had a higher relative growth rate of shoots and roots than the two legumes and developed a more extensive root system. Experiment 2 consisted of growing binary mixtures of the three species at different densities. The effect of competition on the biomass of biserrula, capeweed, and subterranean clover was best modelled by a power–exponential model. Increasing capeweed densities suppressed the biomass production of both biserrula and subterranean clover, whereas capeweed biomass increased with increasing densities of subterranean clover. This study suggests that the competitive advantage of capeweed is mainly conferred during the seedling stage. It also suggests that biserrula and subterranean clover germinating at the same time can co-exist as a mixed sward, at least up until flowering, if biserrula density is high relative to subterranean clover.
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Harries, Martin, Ken C. Flower, and Craig A. Scanlan. "Sustainability of nutrient management in grain production systems of south-west Australia." Crop and Pasture Science 72, no. 3 (2021): 197. http://dx.doi.org/10.1071/cp20403.
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Balancing nutrient inputs and exports is essential to maintaining soil fertility in rainfed crop and pasture farming systems. Soil nutrient balances of land used for crop and pasture production in the south-west of Western Australia were assessed through survey data comprising biophysical measurements and farm management records (2010–15) across 184 fields spanning 14 Mha. Key findings were that nitrogen (N) inputs via fertiliser or biological N2 fixation in 60% of fields, and potassium (K) inputs in 90% of fields, were inadequate to balance exports despite increases in fertiliser usage and adjustments to fertiliser inputs based on rotations. Phosphorus (P) and sulfur (S) balances were positive in most fields, with only 5% returning losses >5 kg P or 7 kg S/ha. Within each of the three agroecological zones of the survey, fields that had two legume crops (or pastures) in 5 years (i.e. 40% legumes) maintained a positive N balance. At the mean legume inclusion rate observed of 20% a positive partial N budget was still observed for the Northern Agricultural Region (NAR) of 2.8 kg N/ha.year, whereas balances were negative within the Central Agricultural Region (CAR) by 7.0 kg N/ha.year, and the Southern Agricultural Region (SAR) by 15.5 kg N/ha.year. Hence, N budgets in the CAR and SAR were negative by the amount of N removed in ~0.5 t wheat grain, and continuation of current practices in CAR and SAR fields will lead to declining soil fertility. Maintenance of N in the NAR was achieved by using amounts of fertiliser N similar to other regions while harvesting less grain. The ratio of fertiliser N to legume-fixed N added to the soil in the NAR was twice that of the other regions. Across all regions, the ratio of fertiliser N to legume-fixed N added to the soil averaged ~4.0:1, a major change from earlier estimates in this region of 1:20 under ley farming systems. The low contribution of legume N was due to the decline in legume inclusion rate (now 20%), the low legume content in pastures, particularly in the NAR, and improved harvest index of lupin (Lupinus angustifolius), the most frequently grown grain legume species. Further quantifications of the effects of changing farming systems on nutrient balances are required to assess the balances more accurately, thereby ensuring that soil fertility is maintained, especially because systems have altered towards more intensive cropping with reduced legume production.
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Lawn, R. J., Hang T. T. Vu, L. M. Bielig, and A. Kilian. "Genetic compatibility among morphotypes of Vigna lanceolata and implications for breeding improved cultivars." Crop and Pasture Science 67, no. 7 (2016): 739. http://dx.doi.org/10.1071/cp16014.
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As well as being part of the wider gene pool of cultivated species such as mungbean and cowpea, Vigna lanceolata Benth. is of agronomic interest as a potentially useful species in its own right. It is widely adapted across northern Australia from the coast to inland desert regions, and possesses attributes that make it potentially suited as a ley, cover crop or pasture legume in seasonally arid tropical environments. The species comprises several morphotypes that variously differ in their broad geographic distribution, life cycle, habit, edaphic adaptation and/or amphicarpy. In order to assess the potential for breeding improved cultivars, eight representative accessions were hybridised in a complete diallel cross and the viability and fertility of the resultant hybrid progeny evaluated. Of the 56 parental combinations in the diallel, 33 resulted in healthy F1 hybrid plants, and of these, nine were at least partly self-fertile. Six of these combinations were the reciprocal crosses between three of the perennial, tuberous-rooted, amphicarpic morphotypes. Another two were the reciprocal crosses between the two annual morphotypes. The patterns of relatedness among accessions indicated by the cross-pollination studies were broadly supported by DArT molecular marker analyses, and suggested that there has been some genetic differentiation within the V. lanceolata complex. Although the process of speciation remains far from complete, the levels of genetic compatibility between some morphotypes would be inadequate to enable a breeding program to draw easily on the full range of genetic diversity within V. lanceolata. Two plausible breeding options are suggested. The first is the development of perennial, tuberous-rooted, amphicarpic ideotypes suited perhaps as pasture or understorey legumes, drawing on selected accessions from the three perennial morphotypes, where there was sufficient genetic compatibility and which collectively have wide geographical spread. The second is an annual, freely seeding, fibrous-rooted, amphicarpic ideotype suited perhaps for use as a self-regenerating ley legume, drawing on selected accessions from the two annual morphotypes.
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Lodge, GM, BR Cullis, and SM Welsby. "Evaluation of pasture legumes sown into a prepared seedbed at Tamworth, New South Wales. 1. Dry matter yield." Australian Journal of Experimental Agriculture 33, no. 3 (1993): 287. http://dx.doi.org/10.1071/ea9930287.
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The potential dry matter production in autumn, winter, and spring of 15 annual and 7 perennial pasture legumes was assessed in ungrazed plots at Tamworth on the Northern Slopes of New South Wales. Seed was sown into a prepared seedbed, and dry matter yield was estimated on 24 occasions from August 1983 to November 1987. The presence of green material at each sampling time. and the actual and total dry matters, were examined. Among the annual legumes, the highest proportion of plots presenting dry matter at all sampling times, and the highest total yields, were found for Trifolium hirtum cv. Hykon (rose clover), T. subterraneum var. subterraneum cvv. Seaton Park and Woogenellup, T. subterraneum var. brachycalycinum cv. Clare (subterranean clovers), and Medicago aculeata (CPI No. 19416). The highest proportion of bare plots and the lowest dry matter yields were found for local ecotypes of the naturalised legumes T. glomeratum, M. minima and M. polymorpha, Astragalus hamosus cv. Ioman (milk vetch), and T. subterraneum var. subterraneum cv. Nungarin. After October (day 300) in 1983-87 the proportions of plots with >10 kg/ha of dry matter present as green material were Clare 85%; Hykon 78%; Woogenellup 74%; M. aculeata, Seaton Park, and Vicia villosa var. dasycalpa cv. Namoi (woolly pod vetch) 67%; M. scutellata cv. Sava (snail medic) 56%; and M. truncatula cv. Sephi (barrel medic) 52%. Total annual yields of Nungarin were often lower than those of the other subterranean clovers, with Clare having the highest yield in each year. Cumulative yields of Namoi declined markedly after 1985, while those of T. lairtum cv. Hykon increased. Little or no linear relationship was found between maturity grading and the relative yield of the annual legumes, although 4 of the 6 highest yielding legumes were late maturing. Among the perennials, yields of M. sativa cv. Pioneer 581 (lucerne) were above average in 1984-87. Lucerne cv. Pioneer 581 produced more dry matter over 5 years than Onobrychis viciifolia cv. Eski (sainfoin), but about the same amount as O. viciifolia cvv. Othello and Remont. Sainfoin production was high in the first 2 years of the experiment, but lower towards the end. The poor performance of T. repens cvv. Haifa and Huia (white clover) was attributed to high temperatures and low effective rainfall in summer. From these data, 5 annuals (Seaton Park, Woogenellup, Clare, Hykon, and M. aculeata) and lucerne show the most potential for sowing as ley pasture in the low elevation, summer rainfall environments of the Northern Slopes of New South Wales.
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Ruz-Jerez, B. E., R. E. White, and P. R. Ball. "A comparison of nitrate leaching under clover-based pastures and nitrogen-fertilized grass grazed by sheep." Journal of Agricultural Science 125, no. 3 (December 1995): 361–69. http://dx.doi.org/10.1017/s0021859600084860.
Full textAbstract:
SUMMARYNitrate leaching was measured under three pastures – perennial ryegrass and white clover, a herbal ley comprising a mixture of legumes, non-aggressive grasses and deep rooting herbs, and perennial ryegrass fertilized with 400 kg N/ha per year as urea – from 1989 to 1991 at Palmerston North, New Zealand (latitude 40° S). The pastures were regularly mob-grazed by sheep at a stocking rate which varied with the amount of feed available. Drainage was estimated from a daily soil water balance and accumulated over 10 day intervals. Nitrate concentrations in the drainage were measured as the volume-averaged concentrations in the soil solution between 30 and 45 cm depth during these intervals. Although the N applied as fertilizer to the grass was 2·5 times greater than the N estimated to have been fixed by the clover-based pastures, the leaching loss from the former was 6–7 times greater than from the latter. The stocking rate on the grass pasture averaged over each year was only 1·2–1·4 times that on the two clover-based pastures. Leaching from urine patches was estimated to account for 55% of the total N leached from the clover-based pastures, but only 25% of the total leached from the N-fertilized grass.The amount of NO3-N leached should be related to the cumulative drainage to determine whether the average nitrate concentration exceeds the environmental safety limit of 10 mg NO3-N/1. In 1989, when the total drainage was 215 mm, 21·5 kg N/ha would have had to be leached for the concentration to exceed the limit and none of the pastures did so. In 1990, when the total drainage was 270 mm, the critical amount to be leached was 27 kg N/ha which was exceeded by the Grass + N400, but not by either the Grass-clover (5.8 kg N/ha) or the Herbal ley (7·3 kg N/ha). The utilization of N was more conservative in the clover-based pastures than in the N-fertilized grass.
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Taylor, GB, and MA Ewing. "Long-term patterns of seed softening in some annual pasture legumes in a low rainfall environment." Australian Journal of Experimental Agriculture 32, no. 3 (1992): 331. http://dx.doi.org/10.1071/ea9920331.
Full textAbstract:
Annual rates of seed softening were determined from 4 lines of burr medic (Medicago polymorpha), 1 barrel medic (M. truncatula), and 1 subterranean clover (Trifolium subterraneum) grown at Merredin in the 1 year. Measurements were also made on one of the lines of burr medic grown in 2 other environments, Gnowangerup and Eneabba, in the same year. Burrs were placed on the soil surface at Merredin and the numbers of residual hard seeds determined each year for up to 5 years in this one environment. Patterns of softening of seeds from the same seed populations were also determined in a laboratory oven with a diurnal temperature fluctuation of 60/15�C. In the field, the softening rates of the 5 medics grown at Merredin were similar, averaging 21% of the original seeds each year for the first 4 years. Seeds of the burr medic grown in a more favourable environment at Eneabba were much slower to soften (averaging 14%); hence, hardseededness in these medics was influenced more by the growing environment than by genotype. More than half of the seeds of subterranean clover softened in the field over the first summer, with declining annual proportions thereafter. There were clear differences between the clover and medics in both pattern and rate of seed softening. The lower seed-softening rate of medics than of subterranean clover was more favourable for ley systems involving frequent cropping, especially in low rainfall areas. Treatment of seeds at 60/15�C simulated field softening for subterranean clover well but produced misleading results for the medics.
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Dalal, Ram C., Weijin Wang, G. Philip Robertson, and William J. Parton. "Nitrous oxide emission from Australian agricultural lands and mitigation options: a review." Soil Research 41, no. 2 (2003): 165. http://dx.doi.org/10.1071/sr02064.
Full textAbstract:
Increases in the concentrations of greenhouse gases, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and halocarbons in the atmosphere due to human activities are associated with global climate change. The concentration of N2O has increased by 16% since 1750. Although atmospheric concentration of N2O is much smaller (314 ppb in 1998) than of CO2 (365 ppm), its global warming potential (cumulative radiative forcing) is 296 times that of the latter in a 100-year time horizon. Currently, it contributes about 6% of the overall global warming effect but its contribution from the agricultural sector is about 16%. Of that, almost 80% of N2O is emitted from Australian agricultural lands, originating from N fertilisers (32%), soil disturbance (38%), and animal waste (30%). Nitrous oxide is primarily produced in soil by the activities of microorganisms during nitrification, and denitrification processes. The ratio of N2O to N2 production depends on oxygen supply or water-filled pore space, decomposable organic carbon, N substrate supply, temperature, and pH and salinity. N2O production from soil is sporadic both in time and space, and therefore, it is a challenge to scale up the measurements of N2O emission from a given location and time to regional and national levels.Estimates of N2O emissions from various agricultural systems vary widely. For example, in flooded rice in the Riverina Plains, N2O emissions ranged from 0.02% to 1.4% of fertiliser N applied, whereas in irrigated sugarcane crops, 15.4% of fertiliser was lost over a 4-day period. Nitrous oxide emissions from fertilised dairy pasture soils in Victoria range from 6 to 11 kg N2O-N/ha, whereas in arable cereal cropping, N2O emissions range from <0.01% to 9.9% of N fertiliser applications. Nitrous oxide emissions from soil nitrite and nitrates resulting from residual fertiliser and legumes are rarely studied but probably exceed those from fertilisers, due to frequent wetting and drying cycles over a longer period and larger area. In ley cropping systems, significant N2O losses could occur, from the accumulation of mainly nitrate-N, following mineralisation of organic N from legume-based pastures. Extensive grazed pastures and rangelands contribute annually about 0.2 kg N/ha as N2O (93 kg/ha per year CO2-equivalent). Tropical savannas probably contribute an order of magnitude more, including that from frequent fires. Unfertilised forestry systems may emit less but the fertilised plantations emit more N2O than the extensive grazed pastures. However, currently there are limited data to quantify N2O losses in systems under ley cropping, tropical savannas, and forestry in Australia. Overall, there is a need to examine the emission factors used in estimating national N2O emissions; for example, 1.25% of fertiliser or animal-excreted N appearing as N2O (IPCC 1996). The primary consideration for mitigating N2O emissions from agricultural lands is to match the supply of mineral N (from fertiliser applications, legume-fixed N, organic matter, or manures) to its spatial and temporal needs by crops/pastures/trees. Thus, when appropriate, mineral N supply should be regulated through slow-release (urease and/or nitrification inhibitors, physical coatings, or high C/N ratio materials) or split fertiliser application. Also, N use could be maximised by balancing other nutrient supplies to plants. Moreover, non-legume cover crops could be used to take up residual mineral N following N-fertilised main crops or mineral N accumulated following legume leys. For manure management, the most effective practice is the early application and immediate incorporation of manure into soil to reduce direct N2O emissions as well as secondary emissions from deposition of ammonia volatilised from manure and urine.Current models such as DNDC and DAYCENT can be used to simulate N2O production from soil after parameterisation with the local data, and appropriate modification and verification against the measured N2O emissions under different management practices.In summary, improved estimates of N2O emission from agricultural lands and mitigation options can be achieved by a directed national research program that is of considerable duration, covers sampling season and climate, and combines different techniques (chamber and micrometeorological) using high precision analytical instruments and simulation modelling, under a range of strategic activities in the agriculture sector.
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Moore, A. D., and P. R. Grace. "Effects of annual pasture composition on subsequent wheat yields in the Waite Permanent Rotation Trial, South Australia." Australian Journal of Experimental Agriculture 38, no. 1 (1998): 55. http://dx.doi.org/10.1071/ea97077.
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Summary. Legume-based annual pastures are commonplace in southern Australian dryland farming systems. By using the long-term wheat and pasture yield records from the Waite Permanent Rotation Trial (established in 1925), we have quantified how changes in the production and composition of a ley pasture will affect subsequent cereal yields and profitability. An analysis of the 1965–89 record reveals that 43% of the variance in wheat yield can be accounted for by the equation: WY = 3.42 + 0.0165AOR – 0.0000165AOR2 + 0.12PL – 2.64PG + 0.39PG2 – 0.019PG3 where WY is wheat yield (t/ha), AOR is April –October rainfall in the wheat year (mm), PL is pasture legume yield in the preceding year (t/ha) and PG is pasture grass yield in the preceding year (t/ha). By comparison with other published data, our results support the claim that nitrogen from legume sources is economically more efficient than fertiliser nitrogen, but the largest effect of increasing legume content comes from avoiding yield loss associated with grassy pastures.
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Angus, J. F., and M. B. Peoples. "Nitrogen from Australian dryland pastures." Crop and Pasture Science 63, no. 9 (2012): 746. http://dx.doi.org/10.1071/cp12161.
Full textAbstract:
Legume-based pastures, particularly those containing a large proportion of lucerne (alfalfa, Medicago sativa), have a prodigious capacity to fix atmospheric N2. Budgets of N show that permanent pastures in south-eastern Australia, when growing with no management limitations, can supply more N than is removed in animal products and can eventually lead to excess soil N. For a mixed crop–livestock farm, legume-dominant ley pastures occupying ~40% of the land area can maintain a stable N balance. The actual performance of pastures on farms normally falls below the potential. Pastures are being replaced by crops in the wheat-sheep zone and, to a lesser extent, in the high-rainfall zone. Pasture productivity, as indicated by the area topdressed, the mean stocking rate, input of superphosphate and sale of pasture legume seed has decreased in the period 1990–2010. It is therefore likely that N2 fixation by pastures is falling sharply in the wheat–sheep zone and is static or falling slightly in the high-rainfall zone. Reversing the decrease in N2 fixation by pastures will become important if the real price of N fertilisers increases, as seems likely because the efficiency of fertiliser synthesis is approaching a maximum and the reserves of natural gas feedstock will eventually be depleted. Increased N2 fixation by pastures will depend on more profitable grazing industries, improved management methods and genotypes, and re-adoption of ley pastures by farmers. There is evidence that profitability of grazing enterprises is approaching that of crops so investment in pasture science is likely to lead to increased N2 fixation.
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Thompson, R. B., and I. R. P. Fillery. "Transformation in soil and turnover to wheat of nitrogen from components of grazed pasture in the south of Western Australia." Australian Journal of Agricultural Research 48, no. 7 (1997): 1033. http://dx.doi.org/10.1071/a96126.
Full textAbstract:
Nitrogen (N) mineralisation from mature subterranean clover (Trifolium subterraneum L.) shoots and roots and from sheep urine and faeces, and N uptake by wheat from the shoots, urine, and faeces, were determined with 15 N in a field study in the Western Australian wheatbelt. Treatments were applied to the soil surface of confined micro-plots in autumn and incorporated into soil immediately before wheat was sown in winter. Mature subterranean clover shoots containing 18 kg N/ha were applied to the soil surface, and root material containing 17 kg N/ha was mixed into soil. 15N-labelled urine and faeces were obtained from housed sheep fed 15N-labelled wheat straw and grain. Urine was applied at the rates of 151 and 301 kg N/ha, and faeces was added at the rate of 47 kg N/ha. There was a loss of 14% of shoot 15N in the 2 months this residue was on the soil surface, although very little mineralisation occurred. On the assumption that wind-blow caused the initial loss of 15N, 28% of shoot N mineralised in 6 months following incorporation of shoot residues into soil, and crop recovery was 11% of the 15N applied. N mineralisation from the mature roots was 26% in 6 months. NH3 volatilisation from urine, estimated by difference, was 25% for high urine (0·517 mL/cm2) and 33% for low urine (0·258 mL/cm2) application rates, the loss occurring in the first 2 weeks. Wheat uptake was 23% of the high urine 15N and 22% of the low urine 15N. Leaching losses from unplanted micro-plots were approximately 25-30% of urine 15N. In contrast, leaching losses from planted micro-plots were estimated to be approximately 10% of urine 15N. Approximately 30% of faecal N was mineralised and recovery of faeces N by wheat was 1% of applied 15N. The relative contributions of these components to N turnover in the ley pasture wheat rotation are discussed. It is concluded that assessments of the potential turnover of N in pastures to cropping phases need to consider the low rates of N mineralisation of above-ground herbage, the potential for supply of N from the total root system, the effect of grazing on NH3volatilisation, and consequent loss of N fixed by legumes.
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Wolfe, E. C., J. A. Paul, and P. D. Cregan. "Monitoring ley pastures and their response to winter cleaning." Australian Journal of Experimental Agriculture 46, no. 8 (2006): 1023. http://dx.doi.org/10.1071/ea04074.
Full textAbstract:
The purposes of this study were to evaluate subterranean clover-based leys on farms and in experiments using several pasture parameters, and to assess the impact of winter cleaning on the productivity and botanical composition of clover swards. Annual pastures were monitored on a group of 5 farms in the Wagga district and compared with an experimental subterranean clover (Trifolium subterraneum L.) pasture. The major problem in the farm paddocks was a lack of legume biomass due to poor legume densities, a consequence of the use of the soft-seeded cultivar Woogenellup and a high content of grassy weeds. The farmers in the group were unaware of the tools, parameters and benchmarks for making quantitative pasture comparisons. In 2 experiments, a range of subterranean clover swards were generated through the use of cultivars, seeding rate and winter cleaning treatments, grazed at 15 sheep/ha and monitored for 3 years. Appropriate benchmark values for the seed pool of subterranean clover were 300–350 kg/ha in winter and 600–700 kg/ha in summer. On the basis of both winter production, a function of May seedling density (target >1000 seedlings/m2) and spring production, which depended on the cultivar maturity, Junee was superior at Wagga to either Dalkeith (earlier maturing) or Woogenellup (softer seeded). Winter cleaning, using selective herbicides (fluazifop, simazine) to remove grasses and weeds, was advantageous in achieving a high content (>90%) and productivity of subterranean clover, provided that the legume content of the pasture was at least 28%, or >20% of total ground area before herbicide application in winter. In winter-cleaned swards, legume growth increased by up to 80%, legume biomass was improved by up to 46% and legume content increased from <50 to >95%. The main disadvantages of winter cleaning were increased areas of bare ground and reduced total biomass for several weeks after herbicide application, and the rapid development of ryegrass that was resistant to at least 1 of the herbicides used. The strategic use of observations to monitor the performance of pastures and their response to management is discussed.
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Winter, WH, RL McCown, and D. Zuill. "Legume-based pasture options for the live cattle trade from the Australian semi-arid tropics." Australian Journal of Experimental Agriculture 36, no. 8 (1996): 947. http://dx.doi.org/10.1071/ea9960947.
Full textAbstract:
The extensive beef industry in the Northern Territory has been based almost exclusively upon native grass pastures for over a century. The recent development of an export trade for live cattle of specific age, weight and type, has increased returns over chilled manufacturing beef exports and has resulted in a demand for improved pastures that can support rapid growth of young cattle. This paper compares the potential of native grass pastures, legume ley pastures and permanent sown grass-legume pastures, in a range of configurations, to meet the market demand. Results of farming systems and sown pasture management experiments conducted at the Katherine Research Station are presented. Data from these experiments and other sources are used to explore options appropriate to the new market. Particular attention has been given to the time required for weaner steers to reach export target weights of 290-300 kg/head and the flexibility of systems to seasonal and animal variability. Permanent sown pastures are sustainable at stocking rates of about 2 steers/ha, but results indicate difficulty in maintaining legume dominance in the ley pastures, particularly if the cropping frequency is reduced. A proposal to use forage crops, rather than grain crops, to deplete soil nitrogen and reduce the incidence of weeds, is discussed. We recommend that ley pastures be retained as part of the management system, despite management difficulties, as they provide higher productivity and greater flexibility for farmers to meet the market requirements.
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McCallum, M. H., M. B. Peoples, and D. J. Connor. "Contributions of nitrogen by field pea (Pisum sativum L.) in a continuous cropping sequence compared with a lucerne (Medicago sativa L.)-based pasture ley in the Victorian Wimmera." Australian Journal of Agricultural Research 51, no. 1 (2000): 13. http://dx.doi.org/10.1071/ar99023.
Full textAbstract:
The nitrogen (N) dynamics (N2 fixation inputs, changes in soil mineral N and total N, N removed in agricultural produce) of a lucerne-based phase farming system (grazed lucerne–annual medic–ryegrass pastures grown in rotation with crops) was compared with that of continuous cropping (cereal, oilseed, and legume pulse crops) in the Victorian Wimmera. The contribution of biological N2 fixation to the N economy of these different systems was strongly linked to biomass production by the legume components of pastures, or field pea in the cropping sequence. The amount of fixed N present in field pea shoots or the total amount of N2 estimated to be fixed by the whole plant (shoots and roots) (121–175 kg N/ha.crop and 181–262 kg N/ha.crop, respectively) was generally greater than the combined measured annual inputs of fixed N by lucerne and annual medic during a pasture ley (40–95 kg N/ha.year in herbage, 80–190 kg N/ha.year in total plant), although large amounts of N were removed in the field pea grain at harvest (115–151 kg N/ha.crop). Over 2 years (1995–96), the seasonal rainfall patterns had a much larger impact on the growth, dry matter production, and N2 fixation of annual medic compared with lucerne. Winter-cleaning of ryegrass from the pasture before cropping resulted in a greater legume content in the pasture and generally increased amounts of fixed N in herbage (by up to 55 kg N/ha.year). Total soil N at depth (0.5–1.0 m) was significantly greater after 2–4 years of pasture than under continuous cropping. In one year (1996), the amount of soil mineral N following a winter-cleaned pasture was greater (by 32–45 kg N/ha, 0–1 m) than after either canola or wheat, producing a yield benefit in a subsequent canola crop that was equivalent to pre-drilling 46 kg N/ha as fertiliser. However, despite some improvements in N fertility, large crop responses to N fertiliser were still observed following pasture. Grain yield was increased by 0.33–0.55 t/ha in canola and by 1.0 t/ha in wheat, grain protein raised by 0.7–2.3% in canola and by 1.3% in wheat, and oil yield in canola enhanced by 124–205 kg/ha with pre-drilled applications of fertiliser N (46 kg/ha). It is speculated that more legume-dominant pastures (>80%) could provide greater flow-on N benefits to farming systems in the Wimmera than the mixed legume–grass swards used in the present study. However, it is likely that a need will remain for supplementary fertiliser N to optimise the nutrition of subsequent non-legume crops in the region.
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Peoples, M. B., R. R. Gault, G. J. Scammell, B. S. Dear, J. Virgona, G. A. Sandral, J. Pau, E. C. Wolfe, and J. F. Angus. "Effect of pasture management on the contributions of fixed N to the N economy of ley-farming systems." Australian Journal of Agricultural Research 49, no. 3 (1998): 459. http://dx.doi.org/10.1071/a97014.
Full textAbstract:
The effects of different management regimes on N2 fixation by subterranean clover (Trifolium subterraneum) in annual pastures and lucerne (Medicago sativa) in perennial-based pastures were examined in 5 experiments and 55 commercial paddocks, in which the pastures were grown in phased rotation with crops. The objectives were to quantify the inputs of fixed N2 and to determine ways of increasing nitrogen (N) inputs into ley-farming systems of southern New South Wales and north-eastern Victoria. Estimates of annual amounts of N2 fixed, based on above-ground herbage production in grazed pastures, ranged from 5 to 238 kg N/ha for subterranean clover and from 47 to 167 kg N/ha for lucerne. Legume reliance upon N2 fixation for growth (Pfix) was high (>65%) in most annual and perennial pastures examined. The levels of Pfix were generally unaffected by management treatments. As a consequence the amounts of N2 fixed were predominantly regulated by the legume content and herbage yield of pastures rather than by any marked differences in the ability of the legume to fix N. When all experimental results were combined with on-farm measurements of N2 fixation, the data indicated that lucerne and subterranean clover fixed 22-25 kg N for every tonne of legume dry matter produced. Management inputs to annual pastures which improved the productivity of subterranean clover and the amounts of N2 fixed included applications of superphosphate and the removal of grass species with herbicide, although the response to these treatments was not consistent across all sites in all years. Potential inputs from N2 fixation were high in annual pastures, and improved management during a good clover season enhanced the levels of mineral N detected in the soil profile (0-200 cm) the following autumn by 100-200 kg N/ha. However, year-to-year variability in annual pasture productivity and clover content resulted in large fluctuations in amounts of N2 fixed. Perennial pastures containing lucerne provided consistently greater annual herbage production, had more stable legume contents, and fixed on average 90-150% more N2 than neighbouring subterranean clover-based pastures. Even during the 1994 drought when annual pastures failed, lucerne still managed to fix >70 kg N/ha. It is proposed that lucerne-based pastures could represent a more reliable means of improving soil fertility for subsequent crops than annual pastures.
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Rozhkova-Timina, I. O., and E. D. Reshetnikova. "Cultivation of Legume and Gramineous Grass Mixtures for Use on Hayfields and Pastures of Southern Sakhalin." IOP Conference Series: Earth and Environmental Science 1112, no. 1 (December 1, 2022): 012060. http://dx.doi.org/10.1088/1755-1315/1112/1/012060.
Full textAbstract:
Abstract Nowadays due of the world population growth, the demand for agricultural products is also growing. To obtain good meat and dairy products, high-quality feed for farm animals is necessary. Legume-gramineous perennial grass mixtures are used to improve fodder lands. Our experience included a test of 9 variants of legume-gramineous grass mixtures, where 6 types of grasses were used: red clover, alfalfa (legumes), meadow timothy grass, orchard-grass, smooth brome-grass, meadow fescue (cereals). The experiments were carried out in four repetitions on the lands of hay and pasture use with the use of fertilizers; there were carried out phenological observations, biometric measurements, and determination of the botanical composition. In herbage from hay fields the smooth brome-grass dominated, and in herbage from pastures the orchard-grass dominated. The proportion of non-sown grass species reaches 26.3-32.7 % in three-component grass mixtures with meadow timothy grass. Meadow fescue and meadow timothy in terms of growth rate, reactions to nitrogen application were inferior to the orchard-grass and smooth bromegrass, which led to their oppression and displacement from the herbage. The best density of plant standing per 1 m2 was noted in the orchard-grass and smooth bromegrass, the smallest - in meadow fescue and alfalfa.
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Yeates, SJ, DG Abrecht, TP Price, WS Mollah, and P. Hausler. "Operational aspects of ley farming systems in the semi-arid tropics of northern Australia: a review." Australian Journal of Experimental Agriculture 36, no. 8 (1996): 1025. http://dx.doi.org/10.1071/ea9961025.
Full textAbstract:
The ley farming systems proposed for the Australian semi-arid tropics involve rotating an annual pasture (usually legume) with crops sown using no-tillage. These systems were developed to overcome many of the climatic constraints that beset previous attempts at cropping in the region. However, difficulties in the timing of farm operations also contributed to past failures. No analysis of the operational aspects of ley farming had been made; this was the objective of this paper. During the transition between wet and dry seasons rainfall is extremely variable. These periods were shown to be the most critical time for operations in ley farming systems. During the dry-wet transition, management of ley pastures is very difficult because pastures must provide grazing for livestock as well as sufficient soil cover for timely sowing of a following crop. Legume pastures have reduced grazing value at this time due to spoilage by early rain. Similarly, during the wet-dry transition annual pastures must be allowed to set seed at a time when crops are yet to be harvested and stubbles are not available for grazing. It was suggested that including separate paddocks of perennial pasture could reduce the demand on annual pastures during the seasonal transitions. A limited number of days to sow a crop combined with severe yield penalties for late sowing restrict the area that can be sown in any season. Sowing opportunities were determined for 3 locations in the Northern Territory. No-tillage was shown to increase the potential number of sowing days. However, the time available to apply glyphosate before sowing using no-tillage was confined to the morning due to risk of afternoon rainshowers reducing efficacy. The number of seasons where a particular crop or cultivar could not be sown was independent of the method of tillage. The wet-dry transition was shown to be important for harvest operations. Our analysis of 3 sites in the Northern Territory suggests that for mungbean and sorghum, later maturity combined with prompt harvest will reduce the risk of poor seed quality due to weathering and could permit earlier sowing. However, for sorghum, an economic assessment of these practices required research that can quantify the interaction between sowing date, time-to-maturity and grain yield.
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Roesner, E. A., N. A. Fettell, and J. Brockwell. "Liming and choice of pasture species improve rhizobial persistence in an acidic chromosol (red-brown earth)." Australian Journal of Experimental Agriculture 45, no. 3 (2005): 247. http://dx.doi.org/10.1071/ea03153.
Full textAbstract:
An experiment was conducted to determine the persistence of soil root-nodule bacteria as influenced by different rates of lime and the previous pasture species. The work was done at Condobolin, central-western New South Wales, on a chromosol (red-brown earth), acidic in the upper profile (pHCa 4.6), which was representative of soils for an extensive region of the eastern Australian wheat belt. In autumn 1997, the experimental area was treated with 4 rates (6.0 t/ha, 3.0 t/ha, 1.5 t/ha, nil) of finely-ground agricultural limestone and sown with 5 pasture species: lucerne (Medicago sativa), barrel medic (M. truncatula), subterranean clover (Trifolium subterraneum), rose clover (T. hirtum) and ryegrass (Lolium rigidum). The pastures were removed with herbicide and cultivation in September 2000. The land lay fallow for 9 months and then was sown to wheat (Triticum aestivum) in autumn 2001 and again in autumn 2002. The most probable numbers of soil (0–10 cm) populations of the root–nodule bacterium for Medicago species (Sinorhizobium meliloti) and for the Trifolium species (Rhizobium leguminosarum bv. trifolii) were counted in May 2001 and May 2002. Soil pH, which was significantly (P<0.05) elevated 12 months after liming, declined substantially during the next 4 years although there was no concomitant decline in the pH of unlimed soil. The pasture species were highly productive of both pasture dry matter and nitrogen. The majority of legume pasture nitrogen was a consequence of symbiotic nitrogen fixation. There was a small but significant (P<0.05) dry matter response to application of lime in lucerne and barrel medic, and a larger nitrogen response to liming in lucerne, barrel medic and rose clover. Nitrogen fixation by rose clover appeared suboptimal. It was assumed from the density of plants that large populations of rhizobia developed in the soil during the growth of the legumes. Nine months after removal of the pasture, rhizobia numbers had fallen to low levels but did not fall further during the following year. The initial fall was attributed to high soil temperatures and low soil moisture during the Condobolin summer. The population of rhizobia for Trifolium species was about twice that of the rhizobia for Medicago species but the difference was not statistically significant. Liming had an overriding influence on the size of rhizobial populations, except in plots that had previously grown ryegrass where numbers remained low irrespective of rate of liming. Overall, most probable numbers escalated with each increase in rate of liming, from 10/g soil in the nil lime plots to 708/g in the 6 t/ha lime plots. The rhizobial homology of the pasture species (i.e. Sinorhizobium meliloti for the Medicago species and Rhizobium leguminosarum bv. trifolii for the Trifolium species) had an underlying but major influence on most probable numbers and in determining which rhizobial species occurred more commonly. Estimated populations of rhizobia in soils from homologous legumes were about 8 times those found in soils from non-homologous legumes. The benefits of applying lime to this red-brown earth soil may not have been merely a consequence of correction of low soil pH; increased levels of calcium may also have had a role. The results are discussed in relation to re-establishment of legume leys after the cereal phase of the cropping system.
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Wolfe, E. C. "Nitrogen Special Issue: summing up of papers and recommendations for future research." Australian Journal of Experimental Agriculture 41, no. 3 (2001): 459. http://dx.doi.org/10.1071/ea00137.
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The 12th Australian Nitrogen Fixation Conference was the third in a series of national workshops that began in 1991 and dealt with aspects of the nitrogen dynamics of Australian pastures and croplands. The conference and the papers published in the Special Issue addressed, at least in part, the slow progress that is evident in improving the rate of biological nitrogen fixation by enhancing inoculating techniques and Rhizobium strains. An important output from the conference was an analysis of nitrogen supply and demand in Australian dryland crops, indicating less reliance on biological nitrogen fixation due to higher wheat yields, the increased use of canola in crop rotations and problems with pulses. In 3 keynote reviews, the factors affecting the fixation and release of biologically fixed nitrogen to non-legume crops were comprehensively detailed. These factors included the frequency of legumes in rotations and their individual biomass rather than the efficiency of nitrogen fixation itself. The further development and use of models is a way of predicting outcomes for various combinations of management and crop rotations. The present trend towards fewer years of legumes in phase farming in Australia may reverse, resulting in renewed interest in ley pastures and pulse crops.
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Hossain, SA, WM Strong, SA Waring, RC Dalal, and EJ Weston. "Comparison of legume-based cropping systems at Warra, Queensland. 2. Mineral nitrogen accumulation and availability to the subsequent wheat crop." Soil Research 34, no. 2 (1996): 289. http://dx.doi.org/10.1071/sr9960289.
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Mineral nitrogen release following legume-based cropping systems for restoring the fertility of a Vertisol and the yield response and N uptake of subsequent wheat crops was studied. Legume phases of pastures, including a 4 year grass+legume ley, and lucerne and medic leys (~1 year) were terminated in October 1988 or 1989 and rotated with wheat. Chickpea-wheat rotations matched those of lucerne and medic leys. Mineral N accumulations during a subsequent fallow period were determined by core sampling to 1.5 m in October, February and May. Grain yield and N uptake of wheat enabled comparisons of the fertility restorative effects of the various systems relative to continuous wheat cropping. Averaged for two fallow periods, increases in mineral N down to 1.2 m depth were 93, 91, 68, and 37 kg/ha following grass+legume, lucerne and medic leys, and chickpea, respectively, compared with the continuous wheat treatment. Wheat yields were generally lower in 1989 (1.85–2.88 t/ha) than in 1990 (2.08–3.59 t/ha) following all leys and crops due to seasonal conditions. There was a grain yield increase of 0.11 and 0.52 t/ha in 1989 and 1.23 and 1.26 t/ha in 1990 following lucerne and medic leys, respectively and 0.85 t/ha in 1990 following a 4 year grass+legume ley. Following chickpea there was a yield increase of 0.81 and 1.36 t/ha in 1989 and 1990 respectively. Nitrogen uptake by wheat was increased by 40 and 49 kg/ha in 1989 and 48 and 58 kg/ha in 1990 following lucerne and medic leys respectively and 63 kg/ha in 1990 following a 4 year grass+legume ley. Following chickpea N uptake by wheat was increased by 27 and 32 kg/ha in 1989 and 1990 respectively. Grain protein concentration of wheat was substantially higher following all pasture leys (11.7–15.8%) than following wheat (8.0–9.4%) or chickpea (9.4–10.1%). Therefore, there was substantial evidence of the effectiveness of pasture leys in soil fertility restoration, as reflected in mineral N, yield response and N uptake by subsequent wheat crops.
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Dimes, JP, RL McCown, and PG Saffigna. "Nitrogen supply to no-tillage crops, as influenced by mulch type, soil type and season, following pasture leys in the semi-arid tropics." Australian Journal of Experimental Agriculture 36, no. 8 (1996): 937. http://dx.doi.org/10.1071/ea9960937.
Full textAbstract:
Past cropping research in the semi-arid tropics of northern Australia has shown that in this climate and on the predominantly sesquioxidic soils, recovery of fertiliser nitrogen (N) by crops is often low. Conceptually, no-tillage, legume ley farming offers features for coping better with the constraints of climate, soil and high fertiliser transport costs to this remote region. This paper summarises the N cycle in a system in which pastures provide N for successive crops, and mulch at the time of crop establishment is provided by the killing of new pasture growth. The aim was further to provide a sound foundation for managing N supply in relation to demand in a climate that causes high variation and uncertainty for pasture N2 fixation and sequestering, the amount of early season re-growth (mulch), rate of mulch decomposition, nitrate leaching losses, and crop growth and N demand. The research approach combined field studies with simulation modelling. A series of field studies that included bare fallow and grass and legume pasture leys on clay loam and sandy loam soils, were conducted at Katherine over 4 wet seasons to study subsequent mineralisation of N. Experimental results were used to test the performance of a simulation model for predicting the observed variations consequent upon the various management options. Experimental results showed that the carbon (C) : N ratio of the residue and soil texture were important factors in determining N mineralisation, immobifisation, and nitrate leaching following chemical kill of pasture leys. However, the greatest variation was between seasons. A modified version of the CERES-Maize N model was able to simulate the accumulation of nitrate following a bare fallow and following pasture leys with high levels (above and below ground) of freshly killed residues with widely differing C:N ratio, the downward movement of nitrate-N in the soil and the interaction of these processes with seasonal rainfall. Despite a capability for simulation of the soil N dynamics in a cropping phase following pasture leys, ex~erimental results indicated how nitrate distribution following leys is influenced by pasture growth during the ley, and how this varied greatly with season and soil texture. The simulation capability reported here has been incorporated elsewhere into the development of a full system model, embracing both the ley phase and the crop phase.
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Shakhane, L. M., J. M. Scott, R. Murison, C. Mulcahy, G. N. Hinch, A. Morrow, and D. F. Mackay. "Changes in botanical composition on three farmlets subjected to different pasture and grazing management strategies." Animal Production Science 53, no. 8 (2013): 670. http://dx.doi.org/10.1071/an11177.
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As part of the Cicerone Project’s farmlet experiment, conducted on the Northern Tablelands of New South Wales, Australia, between July 2000 and December 2006, this study assessed the effects of varying soil fertility, pasture species and grazing management on the botanical composition of three 53-ha farmlets subjected to different management strategies. Starting with the same initial conditions, the farmlets were managed to reach different target levels of soil phosphorus (P) and sulfur (S); Farmlet A aimed at 60 mg/kg of Colwell P and 10 mg/kg S (KCl40) whereas Farmlets B and C both aimed at 20 and 6.5 mg/kg of P and S, respectively. Pastures were renovated on six out of eight paddocks on Farmlet A, but only one paddock of each of Farmlets B (typical management) and C (intensive rotational grazing) was renovated. Flexible rotational grazing was employed on Farmlets A and B (each of eight paddocks) while Farmlet C used intensive rotational grazing over its 17 major paddocks, which were further subdivided into 37 subpaddocks. This paper focuses on the botanical composition dynamics observed across all three farmlets and the explanatory variables associated with those changes. Eight assessments of botanical composition were carried out at approximately annual intervals across each of the 37 major paddocks distributed across the farmlets and the results for each of 49 species were aggregated into seven functional groups for analysis. The strongest correlation found was a negative curvilinear relationship between sown perennial grasses (SPG) and warm-season grasses (WSG). The most significant factors affecting the functional group changes were soil P, sowing phase, paddock and date. These factors led to significant increases in SPG and correspondingly lower levels of WSG on Farmlet A compared with Farmlet B. Farmlets B and C experienced similar, declining levels of SPG, and increasing levels of WSG suggesting that intensive rotational grazing did not lead to substantial changes in botanical composition, compared with flexible rotational grazing, in spite of the fact that intensive rotational grazing had much longer grazing rests and shorter graze periods than the other two farmlets. Soil P levels were also significantly associated with levels of cool-season annual grasses, legumes and herbs, especially on Farmlet A. In general, the largest differences in botanical composition were between Farmlet A and the other two farmlets; these differences were most closely associated with those plants categorised as sown, introduced, C3 pasture species. The levels of legume were generally low on all farmlets, due largely to the dry seasons experienced over most of the trial. Efforts to increase the legume composition on all farmlets were more successful on Farmlet A than on the other two farmlets due, presumably, to higher soil fertility on Farmlet A. Farmlet C, with its long rest periods and short graze periods, had a small proportion of legumes, due to the competitive effects of the accumulated tall grass herbage between grazings. The ‘typical’ management of Farmlet B also resulted in low levels of legume as well as increased ‘patchiness’ of the pastures and increased numbers of thistles.
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Lagrange, Sebastian, Karen Beauchemin, Jennifer MacAdam, and Juan J. Villalba. "94 President Oral Presentation Pick: Grazing diverse combinations of tanniferous and non-tanniferous legumes: Implications for beef cattle performance and environmental impact." Journal of Animal Science 98, Supplement_4 (November 3, 2020): 76–77. http://dx.doi.org/10.1093/jas/skaa278.139.
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Abstract We tested the effect of increasingly diverse combinations of tanniferous legumes (birdsfoot trefoil-BFT, sainfoin-SF) and alfalfa (ALF) on cattle performance, methane (CH4) emissions and nitrogen (N) balance. Pairs of heifers (401 ± 49.6 kg) grazed three spatial replications of 7 treatments (n = 3/treatment): monocultures (BFT, SF, ALF) and all possible 2- and 3-way choices among strips of these legumes in a completely randomized block design of two 15-d periods during 2 consecutive years. Average daily gains (ADG) of heifers grazing the tanniferous legumes (1.05 kg/d) were 40% greater (P < 0.10) than of heifers grazing ALF (0.74 kg/d) during the first year. Heifers grazing the 3-way choice had greater intakes (10.4 vs 7.8 kg/d; P = 0.064) and ADG (1.21 vs. 0.95 kg/d, P = 0.054) than those grazing monocultures, suggesting a nutritional synergism among legumes. The average CH4 emissions for legume monocultures vs. 2- and 3-way choices was 222 vs. 202 and 162 g/kg BW gain (P > 0.10), respectively. For heifers grazing SF and BFT compared with ALF, blood urea N was less (14.3 and 16.8 vs 20.8 mg/dL; P < 0.05) as were urinary N concentrations (3.7 and 3.5 vs 6.0 g/L; P < 0.05), but fecal N concentrations were greater (34.5 and 35.5 vs 30.5 g/kg, respectively; P < 0.05). Combining both tanniferous legumes (SF-BFT) led to the greatest declines in urinary N (2.24 g/L) and urea-N (1.71 g/L) concentration, suggesting that different types of tannins in different legume species result in associative effects that enhance N economy. In addition, heifers grazing 3-way choices partitioned less N into urine (40.7 vs 50.6%; P = 0.037) and retained more N (36.1 vs 25.2%, P = 0.046) than heifers grazing monocultures. In summary, combinations of tanniferous legumes with alfalfa improved animal performance and reduced environmental impacts relative to monocultures, resulting in a more sustainable approach to beef production in pasture-based finishing systems.
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Taylor, G. B. "Hardseededness in Mediterranean annual pasture legumes in Australia: a review." Australian Journal of Agricultural Research 56, no. 7 (2005): 645. http://dx.doi.org/10.1071/ar04284.
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Hardseededness (seed coat impermeability) is the main seed dormancy mechanism for regulating germination of annual pasture legumes both within and between years. Progress made in Australia over the past 30 years towards an understanding and better utilisation of the mechanism is the subject of this review, together with relevant overseas studies. Although some legumes produce virtually no hard seeds, newly ripened seeds of most cultivated annual pasture legumes are >90% hard when produced under favourable seed maturation conditions. The pattern of seed softening (loss of impermeability) varies widely among legumes both within and between years and is one of the more important considerations in selection programs. The many factors that influence the longevity of seed hardness are described. Differences among legumes in patterns of summer and autumn seed softening, which may influence the extent of seed losses through false breaks of season, are explained in terms of a 2-stage conceptual model of the seed softening process. This model has led to the development of laboratory techniques that effectively simulate field softening behaviour in a wide range of legumes. Different rates of seed imbibition, which may be attributable to a previously unrecognised stage in the seed softening process, and which can offer some further protection against false breaks of season are also described. The wide range of seed softening characteristics that are now recognised provides opportunities for better adapting pasture legumes to particular management systems, including rotations with crops.
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Kelly, Jane, Allison Chambers, Paul Weston, William Brown, Wayne Robinson, John Broster, and Leslie Weston. "The Impact of Herbicide Application and Defoliation on Barley Grass (Hordeum murinum subsp. glaucum) Management in Mixed Pasture Legumes." Agronomy 10, no. 5 (May 11, 2020): 671. http://dx.doi.org/10.3390/agronomy10050671.
Full textAbstract:
Barley grass (Hordeum murinum subsp. glaucum.) is an annual weed associated with grain revenue loss and sheep carcass damage in southern Australia. Increasing herbicide resistance led to a recent investigation into effective integrated weed management strategies for barley grass in southern Australia. Field studies in Wagga Wagga, New South Wales (NSW) during 2016 and 2017 examined the effect of post-emergent herbicide applications and strategic defoliation by mowing on barley grass survival and seed production in a mixed legume pasture. Statistically significant differences between herbicide-only treatments in both years showed propaquizafop to be more than 98% effective in reducing barley grass survival and seed production. Paraquat was not effective in controlling barley grass (58% efficacy), but led to a 36% and 63.5% decrease in clover and other weed biomass, respectively, after 12 months and increased lucerne biomass by over three-fold after 24 months. A single repeated mowing treatment resulted in a 46% decline in barley grass seedling emergence after 12 months and, when integrated with herbicide applications, reduced other weed biomass after 24 months by 95%. Resistance to acetyl-CoA carboxylase (ACCase)-inhibiting herbicides observed in local barley grass populations led to additional and more focused investigation comparing the efficacy of other pre- and post-emergent herbicides for barley grass management in legume pastures. Haloxyfop-R + simazine or paraquat, applied at early tillering stage, were most efficacious in reducing barley grass survival and fecundity. Impact of defoliation timing and frequency on barley grass seedlings was also evaluated at various population densities, highlighting the efficacy of repeated post-inflorescence defoliations in reducing plant survival and seed production. Results highlight the importance of optimal environmental conditions and application timing in achieving efficacious control of barley grass and improving pasture growth and biomass accumulation.
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Coates, DB, P. Schachenmann, and RJ Jones. "Reliability of extrusa samples collected from steers fistulated at the oesophagus to estimate the diet of resident animals in grazing experiments." Australian Journal of Experimental Agriculture 27, no. 6 (1987): 739. http://dx.doi.org/10.1071/ea9870739.
Full textAbstract:
The legume content of the diet of groups of resident cattle (LDR) continuously grazing a number of grass-stylo pastures was determined by the faecal carbon isotope ratio (�13C) technique on various occasions. At the same time the pastures were sampled by non-resident steers fistulated at the oesophagus (OF steers) and the legume content of their extrusa (LEO) was determined. Overall, the linear relationship between LEO and LDR had a coefficient of determination (r2) of only 0.127, indicating that LDR could not be reliably predicted from LEO. The LEO of morning samples was often markedly different from LEO of afternoon samples. The implications of the results for diet selection work on grass-legume pastures using OF animals are discussed. Researchers need to recognise that quality attributes of extrusa collected from OF animals do not necessarily reflect those of the diet of resident test animals.
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Kirby, GWM, VJ Hristova, and S. Murti. "Conservation tillage and ley farming in the semi-arid tropics of northern Australia - some economic aspects." Australian Journal of Experimental Agriculture 36, no. 8 (1996): 1049. http://dx.doi.org/10.1071/ea9961049.
Full textAbstract:
This paper examines some aspects of the economics of conservation tillage and ley farming in the semi-arid tropics of northern Australia. The distribution, 1 value and major trends in the enterprises comprising the agricultural sector of the semi-arid tropics are discussed in an industry context. The likely economic benefits for the farmer from the adoption of conservation tillage and ley farming come from mulch retention and increased yields. These benefits vary with the frequency of grain cropping, the legume species used and the commodity price relativities. The benefits are likely to be larger in drier growing seasons. Data on other factors, such as soil type and seasons, were inadequate for economic analysis. Some ley farming systems are more profitable than single enterprises in the short term. In the long term, the best choice for sustainable farming systems in the semi-arid tropics appears to be a legume pasture system or a legume pasture-crop system. Results to date from ley farming studies show that experimental designs need to be modified to incorporate higher cropping frequencies and more comprehensive joint product measures in order to allow a more critical economic assessment. Additional benefits to society from the adoption of conservation tillage and ley farming are likely to come from minimising adverse on-farm and off-farm effects of agricultural activities. There are strong arguments for continuing support for research and development in ley farming technology and a joint sharing of the costs between farmers and the community generally.
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Dunn, BW, and HG Beecher. "Green manuring legume pasture for aerial-sown rice." Australian Journal of Experimental Agriculture 34, no. 7 (1994): 967. http://dx.doi.org/10.1071/ea9940967.
Full textAbstract:
The potential for suppling a portion of the required nitrogen (N) for aerial-sown rice crops by green manuring legume pasture was investigated in southern New South Wales. Green pasture material could be the source of up to 300 kg N/ha in the southern New South Wales ricegrowing systems. Three experiments were conducted over 2 seasons. Each included 3 land preparation treatments (fallow, pasture removed, pasture incorporated) split for 5 rates of N (0, 40, 80, 120, 160 kg N/ha) applied as urea immediately before flooding for aerial sowing. In all experiments fallow resulted in lower anaerobic incubation soil ammonium levels at flooding than the pasture-incorporated treatment. When the fallow was extended, N losses led to a decrease in grain yield. The incorporation of green manure resulted in an increase in grain yield at the nil N rate in experiment 1, where soil N levels were comparatively low and seasonal temperatures average. In experiment 2, where soil N levels were high and the temperatures before panicle initiation below average, the incorporation of green manure reduced total dry matter and increased per cent unfilled grain. Land preparation treatments did not affect total dry matter or grain yield in experiment 3, where a short season variety was grown and all treatments lodged severely. Grain yields in all experiments were affected by a season x soil fertility x variety interaction.
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Suriyagoda, Lalith D. B., Hans Lambers, Megan H. Ryan, and Michael Renton. "Effects of leaf development and phosphorus supply on the photosynthetic characteristics of perennial legume species with pasture potential: modelling photosynthesis with leaf development." Functional Plant Biology 37, no. 8 (2010): 713. http://dx.doi.org/10.1071/fp09284.
Full textAbstract:
Age-dependent changes in leaf photosynthetic characteristics (i.e. parameters of the light response curve (maximum photosynthetic rate (Pmax), quantum yield (Φ) and the convexity parameter (θ)), stomatal conductance (gs) and dark respiration rate (Rd)) of an exotic perennial legume, Medicago sativa L. (lucerne), and two potential pasture legumes native to Australia, Cullen australasicum (Schltdl.) J.W. Grime and Cullen pallidum A. Lee, grown in a glasshouse for 5 months at two phosphorus (P) levels (3 (P3) and 30 (P30) mg P kg–1 dry soil) were tested. Leaf appearance rate and leaf area were lower at P3 than at P30 in all species, with M. sativa being the most sensitive to P3. At any leaf age, photosynthetic characteristics did not differ between P treatments. However, Pmax and gs for all the species and Φ for Cullen species increased until full leaf expansion and then decreased. The convexity parameter, θ, did not change with leaf age, whereas Rd decreased. The estimates of leaf net photosynthetic rate (Pleaf) obtained through simulations at variable Pmax and Φ were lower during early and late leaf developmental stages and at lower light intensities than those obtained when Φ was assumed to be constant (e.g. for a horizontally placed leaf, during the 1500°C days developmental period, 3 and 19% reduction of Pleaf at light intensities of 1500 and 500 µmol m–2 s–1, respectively). Therefore, developmental changes in leaf photosynthetic characteristics should be considered when estimating and simulating Pleaf of these pasture species.
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Jones, RK, ME Probert, NP Dalgliesh, and RL McCown. "Nitrogen inputs from a pasture legume in rotations with cereals in the semi-arid tropics of northern Australia: experimentation and modelling on a clay loam soil." Australian Journal of Experimental Agriculture 36, no. 8 (1996): 985. http://dx.doi.org/10.1071/ea9960985.
Full textAbstract:
Two experiments on a Tippera clay loam soil (alfisol) at Katherine, Northern Territory, investigated the nitrogen (N) benefit from legume pasture leys of Caribbean stylo (Stylosanthes hamata cv. Verano) to subsequent maize crops. Nitrogen uptake and yield of the maize crops were higher after the Verano leys than after a grass ley, the effect persisting into the second crop. The 1-year Verano ley was estimated to have increased N uptake by the maize crops by about 30 kg/ha, and the 3-year ley by about 55 kgha over that for the grass. Removing some of the Verano dry matter (DM) as hay at the end of each growing season reduced the subsequent benefit compared with treatments where the Verano DM was rotovated into the surface soil at the end of each growing season, or left standing. However, in all legume treatments, the additional N contributed by the legume was inadequate to fully meet the N requirement of the following crop. The main features of the experimental results, through both the ley and cropping phases, could be simulated adequately using the cropping system model APSIM. The model provided the opportunity to explore the fate of N in the system, and gave insights into aspects of system performance that could not be obtained from the experimental data.
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Young, Douglas L. "Policy barriers to sustainable agriculture." American Journal of Alternative Agriculture 4, no. 3-4 (December 1989): 135–43. http://dx.doi.org/10.1017/s0889189300002964.
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AbstractU.S. agriculture, which has developed in a mixed environment of private initiative and government support, is very successful by many measures. American farmers produce record levels of food and fiber per farm worker at very low budgetary cost to consumers. Recently, however, concern about resource depletion and agrichemical pollution has caused critics to question the environmental sustainability of the agricultural production system. Furthermore, pressures to trim the growing contribution of agricultural subsidies to the national budget deficit have led legislators and others to question the sustainability of the federal farm programs. Low agrichemical input or sustainable agricultural practices, such as nitrogen-fixing legumes in rotation with cereals, could reduce environmental damage. The selectivity and structure of historical farm programs, however, have economically favored conventional systems. Farm programs subsidize only about half the total value of agricultural products. Feed and food grains, cotton, and dairy products receive the lion's share of payments. Soil-building crops like forage legumes, most edible legumes, hay, and pasture are excluded. Secondly, the structure of commodity programs favors intensive production of program crops supported by high fertilizer and pesticide applications. This incentive emanates from the policy of computing the farm-wide deficiency payment for a program crop proportionately to the farm's historical “base” acreage and “established” yield for the crop. The leading farm program crops of corn, wheat, cotton, and soybeans occupied slightly over 60 percent of cropped acres and received at least 65 percent of all U.S. agricultural pesticides and fertilizer in the mid 19809s. Despite budget pressures and environmental concerns, near term termination of farm programs or decoupling them from production of particular commodities is unlikely. Fears about aggravating financial stress, reducing land values, and harming agrichemical supply businesses in program crop-growing regions will promote cautious incremental change. Recent promising signs of “creeping decoupling” include the 1986 freeze on established yields, the gradual reduction in target prices, the permitting of multi-year grass or legume plantings as set aside acreage, and the loosening of base acreage restrictions within the 1988 Drought Relief Bill.
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Chapman, D. F., M. R. McCaskill, P. E. Quigley, A. N. Thompson, J. F. Graham, D.Borg, J. Lamb, G. Kearney, G. R. Saul, and S. G. Clark. "Effects of grazing method and fertiliser inputs on the productivity andsustainability of phalaris-based pastures in Western Victoria." Australian Journal of Experimental Agriculture 43, no. 8 (2003): 785. http://dx.doi.org/10.1071/ea02198.
Full textAbstract:
The effects of combinations of different fertiliser rates and grazing methods applied to phalaris-based pastures on an acid, saline, yellow sodosol on the Dundas Tablelands of western Victoria (mean annual rainfall 623�mm) were measured from 1997 to 2000. The objective was to help identify management systems that improve phalaris growth and persistence, water use, and animal production, and thereby the productivity and sustainability of grazing systems. Pastures were either set stocked with low [mean 6.4 kg phosphorus (P)/ha.year] or high (mean 25 kg P/ha.year) fertiliser rates, or rotationally grazed with high fertiliser (mean 25 kg P/ha.year). Rotational grazing was implemented as either a simple '4-paddock' system (fixed rotation length), or a more intensive system where rotation length varied with pasture growth rate. Unreplicated paddocks of volunteer pasture (dominated by onion grass and annual grass weeds) receiving an average of 8 kg P/ha.year were also monitored. All treatments were stocked with spring-lambing Merino ewes. Stocking rate was an emergent property of each treatment, and was driven by pasture quality and availability. Total pasture herbage accumulation ranged from 7150 to 9750 kg DM/ha.year and was significantly lower on the set-stocked, low-fertility treatment than on all other treatments. A significant treatment.day effect in the spline analysis of herbage mass was explained by a trend toward higher pasture mass in the rotationally grazed treatments than set-stocked treatments from the break of season until mid-spring. Rotational grazing led to significantly higher phalaris herbage accumulation than set stocking (mean 3680 v. 2120 kg DM/ha.year), but significantly lower subterranean clover herbage accumulation (1440 v. 2490 kg DM/ha.year). Despite the stronger growth of deep-rooted phalaris in the rotationally grazed treatments, maximum soil water deficits at the end of summer differed only slightly between treatments, with the difference between driest and wettest treatments amounting to only 14 mm. Summer growth of phalaris was apparently insufficient to generate significant differences in soil water extraction at depth, even when phalaris content was increased by rotational grazing, and re-wetting of the soil profile occurred at a similar rate for all treatments. Rotationally grazed treatments supported higher stocking rates than set-stocked treatments at high fertiliser rates (mean 14.9 v. 13.7 ewes/ha), but apparent losses in pasture feeding value due to lower legume content under rotational grazing meant that there were few significant differences between treatments in lamb production per hectare. The experiment showed that grazing method can have a substantial and rapid effect on pasture botanical composition. There are clear opportunities for producers to use temporal and spatial combinations of set stocking and rotational grazing to manipulate herbage mass and pasture composition within broad target ranges for achieving both animal production (e.g. high per-head animal performance) and sustainability (e.g. persistence of perennial grasses) objectives. Rigid application of either set stocking or rotational grazing imposes limitations on both pasture and animal production, and neither grazing method will optimise system performance under all conditions. The experiment also demonstrated that management and land-use changes that have much greater potential to increase water use than those examined here will be needed to ensure the sustainability of pasture systems in the high rainfall zone of western Victoria.
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Иванова, Н., А. Капсамун, and Н. Амбросимова. "Forage and environment-forming potential of pasture grasses on the drainage land of the Central Non-Chernozem region." Кормопроизводство, no. 4(2019) (April 12, 2019): 12–16. http://dx.doi.org/10.25685/krm.2019.2019.28245.
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Исследования проводились в 2012-2017 годах на агроэкологическом полигоне ФГБНУ «ВНИИМЗ» на осушаемой дерново-подзолистой супесчаной почве различной степени оглеения. В статье изложены результаты оценки кормовой и средообразующей роли злаковых и бобово-злаковых травостоев. Приводятся данные по накоплению подземной массы и закреплению в ней основных элементов питания растений в зависимости от местообитания трав и вида применяемых удобрений. Экспериментальные данные по влиянию используемых удобрений и условий местообитаний на формирование злакового и бобово-злакового травостоев показали, что в условиях мелиорированных земель изучаемые агрофитоценозы имеют достаточно хорошую адаптационную способность. В среднем за 5 лет по фону без удобрений на бобово-злаковом травостое получено 6,4–6,7 т/га сухого вещества, что на 1,6–2,2 т/га больше, чем урожайность злакового травостоя. Органическая система удобрений (запашка компоста многоцелевого назначения — КМН) не давала ощутимого прироста продуктивности бобово-злакового травостоя. По качественным показателям КМН полностью удовлетворял требованиям технических условий его применения. Под влиянием минерального азота на злаковом травостое сформировался монозлаковый травостой с доминированием ежи сборной, а на фоне КМН — разнотравно-злаковый. Установлено, что благодаря формированию большой корневой массы (10,5–13,2 т/га) с высоким содержанием азота, фосфора, калия и кальция луговые агрофитоценозы были хорошими гумусообразователями, способствовали сохранению и повышению плодородия осушаемых почв и служили благоприятными предшественниками для последующих полевых культур, возделываемых в регионе. Investigations took place at the All-Russian Research Institute of Meliorated Lands on the drained sod-podzolic sandy gleyificated soil. This report deals with forage and environment-forming potential of gramineous and their mixtures with legumes. The paper includes the data on root formation and nutrient accumulation as affected by habitat and fertilizers. Crop ecosystems adapted well to the conditions of meliorated lands. For 5 years legume-gramineous mixtures yielded 6.4–6.7 t ha-1 of dry matter under zero fertilization, exceeding gramineous by 1.6–2.2 t ha-1. Plowing multi-purpose compost under had insignificant effect on legume-gramineous mixtures. Quality of multi-purpose compost met the requirements of the Standard. Monoculture of gramineous formed under the application of mineral nitrogen; cocksfoot prevailing. Use of multi-purpose compost led to the development of mixed ecosystems. Grassland ecosystems effectively formed humus, maintained and increased soil fertility and performed as efficient preceding crops due to the development of large root system (10.5–13.2 t ha-1) containing high concentrations of N, P and K.
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Dowling, PM, DR Kemp, DL Michalk, TA Klein, and GD Millar. "Perennial Grass Response to Seasonal Rests in Naturalised Pastures of Central New South Wales." Rangeland Journal 18, no. 2 (1996): 309. http://dx.doi.org/10.1071/rj9960309.
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The influence of grazing management, herbicide and fertiliser on botanical change in two perennial grass based pastures was assessed over six years at two sites in central New South Wales. Ten treatments at both sites compared continuous grazing, three seasonal rests from grazing (autumn, winter, summer), and herbicide application for seedling grass control, each at two levels of fertiliser addition (nil, recommended). These treatments were designed to screen options for management rather than devise complete systems. In a degraded perennial pasture dominated by annual grasses, the proportion of perennial grasses and forbs increased with summer rests, especially at the recommended fertiliser level. Legumes increased with herbicide application, and annual grasses remained high in the continuously grazed control and other treatments. There were no significant effects on composition from autumn or winter rests. On the summer rest treatment at the recommended fertiliser level, perennial grasses (mostly cocksfoot) increased from 11% to 30% compared with the control where perennial grass declined below 5%. The increase was due to both recruitment and increase in size of existing plants, as a consequence of resting the perennial grasses when actively growing, flowering and setting seed, in favourable seasons. In contrast, on the better quality perennial pasture dominated by phalaris, there were limited management effects and perennial grasses increased on all treatments over time. The absence of a response at this site was attributed to a lenient stocking rate, dominant perennial grasses and limited rainfall during periods when active growth might be expected. Summer rests in this case also led to a small increase in forbs. The data suggest that perennial grasses can be encouraged with a conservative stocking policy that maintains the available feed-on-offer above 1 t DM/ha through seasons of active growth.
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Grebennikov, V. G., I. A. Shipilov, O. V. Khonina, and L. R. Ashibokova. "Ways to improve low-yield hayfields and pastures in arid areas." Agrarian science, no. 7-8 (September 24, 2021): 81–84. http://dx.doi.org/10.32634/0869-8155-2021-351-7-8-81-84.
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Relevance. An analysis of the development of feed production in the Stavropol Territory shows that at present, due to the low productivity of natural forage lands, the level of feed production does not meet the requirements for the development of animal husbandry. Illiterate anthropogenic influence in the dry-steppe regions of the region, where about 70% of the number of sheep and 30% of the number of beef cattle are located, led to the fact that up to 300 thousand hectares of hayfields and pastures were subjected to erosion and deflation. However, in recent years, the process of improving forage land has been reduced to a minimum. Therefore, the process of restoring the forage productivity of hayfields and pastures should be given close attention. To this end, in the zone of dry steppes we conducted research on the selection of perennial legumes and grasses of a new generation to create highly productive grassland agrophytocenoses of long-term use.Methods. The experiments were carried out in the conditions of arid and extremely arid zones of the Stavropol Territory. The objects of research were perennial legumes and cereals and their herb mixtures. Restoration of degraded hayfields and pastures was carried out by means of amelioration and superficial improvement.Results. According to our research, by enriching the degenerated grass with valuable legumes and cereals in terms of forage it is possible to significantly increase its productivity and quality. In extremely arid and arid zones the most effective mixtureswere ones involving 4 and 5 components, which yield reached 15.3–23.8 t/ha of green mass, and the yield of feed units per 1 ha was 1.9–2.6 t/ha. The increase in the productivity of the improved herbage had a positive effect on the feed capacity of the land, which increased to 0.83–1.30 conventional heads per 1 ha.
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Hossain, SA, RC Dalal, SA Waring, WM Strong, and EJ Weston. "Comparison of legume-based cropping systems at Warra, Queensland. 1. Soil nitrogen and organic carbon accretion and potentially mineralisable nitrogen." Soil Research 34, no. 2 (1996): 273. http://dx.doi.org/10.1071/sr9960273.
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Effects on soil nitrogen accretion and potentially mineralisable nitrogen were studied as part of a long-term field experiment established in 1986 to test alternative legume-based systems for restoring fertility in a Vertisol. Organic C accretion was also measured to ascertain the changes in organic matter content. The systems, which were studied only during 1989 and 1990, were a grass+legume ley (purple pigeon grass, Rhodes grass, lucerne, annual medics) of 4 years duration followed by wheat; a 2-year rotation of wheat (lucerne undersown) and lucerne; a 2-year rotation of wheat (medic undersown) and medic; a 2-year rotation of chickpea and wheat; and continuous wheat as control. Soil total N and organic C significantly increased in the 0–10 cm soil layer only under the grass+legume ley. There was no significant change in the soil C/N ratio. Plant residues contained from 52 to 104 kg N/ha in 1990 at the end of the legume phase, with high values for root N in the grass+legume ley. A comparison of N accretion versus fixation at the end of the legume-based systems in 1990 showed that net accumulation of N exceeded fixation in soil under lucerne and grass+legume leys; in the latter, net accumulation of 779 kg N/ha over 3.75 years was measured compared with 384 kg N/ha for N2 fixation. Part of the accumulation of N may have been due to uptake of NH4-N from the deep subsoil. Although values for soil mineral N (0–120 cm) were low at the end of all the legume-based systems, a deep subsoil (120–300 cm) accumulation of NH4-N was found in all treatments. The nitrogen mineralisation potentials (No) for 0–10 cm depth samples taken at the end of the legume phase in 1989 were higher in all the legume-based systems (105–182 mg N/kg) than the wheat control (57 mg N/kg). The rapid biological tests of N availability, both waterlogged and aerobic incubation, were more sensitive to treatment differences than No, in the surface and subsoil (range 12–78 mg N/kg for 0–10 cm soil for the waterlogged procedure). The rapid chemical tests, hot KCl extraction and the autoclave index, showed small treatment effects and did not appear to be useful availability indices. The pasture management (graced v. mown and removed) had no significant effect on total N, organic C and N availability indices in this alkaline Vertisol during the study period.
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Silburn, D. M., P. E. Tolmie, A. J. W. Biggs, and M. H. Crawford. "Effects of farming systems, tillage, and traffic practices on deep drainage and soil salt loads in the Queensland Murray–Darling and Fitzroy Basins using soil chloride." Soil Research 60, no. 3 (November 29, 2021): 262–78. http://dx.doi.org/10.1071/sr21084.
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Context Cropping in the Queensland Murray–Darling and Fitzroy Basins has precursors for secondary salinity – high soil salt loads and increased drainage after clearing. Aims To measure changes in deep drainage, for key tillage, traffic, and cropping systems. Methods Steady-state and transient chloride (Cl) mass-balance were applied to Cl profiles from four tillage and crop rotation trials and one controlled traffic trial in southern and central Queensland, to determine deep drainage below the root zone. Key results Large downward movement of Cl occurred after clearing. Deep drainage from transient Cl balance for cropping was a small proportion of rainfall but considerably higher than under native vegetation. Deep drainage was consistently greater under zero than conventional tillage, for both winter and summer cropping. For example, deep drainage was greatest for zero tillage (∼45 mm/year) and least for conventional, stubble mulch, and reduced tillage (2–6.3 mm/year) at the highest-rainfall site (677 mm/year). Deep drainage was 12.7 and 7.9 mm/year for zero and conventional tillage, respectively, at the lowest-rainfall site (497 mm/year). Drainage under continuous wheat conventional tillage was more than twice that where some summer crops were included. At Billa Billa, continuous wheat had greater deep drainage by three to five times than continuous sorghum for three of four tillage systems. No drainage was detected during 6 years of opportunity cropping. A pasture legume ley had only 1.7 mm/year of deep drainage. Deep drainage was less for compacted than non-compacted treatments (23.3 vs 38.2 mm/year). Conclusion and implications Increased deep drainage with zero tillage and controlled traffic can be reduced using summer crops, particularly opportunity cropping where crops are planted when soil water is sufficient, and ley pastures.
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Street, K. A., A. M. Abd El Moneim, and P. S. Cocks. "The performance of subterranean vetch (Vicia sativa ssp. amphicarpa) in a cereal/pasture rotation in north-west Syria." Australian Journal of Agricultural Research 53, no. 5 (2002): 609. http://dx.doi.org/10.1071/ar01126.
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The aim of this study was to determine if subterranean vetch can persist in a cereal–legume ley farming system and to determine when it is most susceptible to grazing. Grazing treatments were applied to a series of plots containing subterranean vetch during the establishment year. Thereafter the plots were alternately sown to barley or left for the vetch to regenerate. Early grazing caused a seed yield reduction of about 75%. Later grazing treatments had no effect on seed yield, which were between 1000 and 1400 kg/ha. The first cereal phase caused a 6–10-fold reduction in seed bank size. During the 2 years following the first barley year, the seed bank increased to about 900 kg/ha. The second barley year caused a 4-fold reduction in the soil seed bank. Although subterranean vetch managed to persist for 5 years, the dramatic reduction in the seed bank after the barley years indicates that subterranean vetch will not persist at a useful density in a system where 2 or more cropping years run successively. However, other studies have shown that there are enough genotypes with the necessary levels of hardseededness to fit the ley system.
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Lane, L. A., J. F. Ayres, and J. V. Lovett. "The pastoral significance, adaptive characteristics, and grazing value of white clover (Trifolium repens L.) in dryland environments in Australia: a review." Australian Journal of Experimental Agriculture 40, no. 7 (2000): 1033. http://dx.doi.org/10.1071/ea99141.
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The importance of white clover as a pasture legume of international significance has led to major investment in research on ecophysiology, germplasm conservation, and white clover improvement. Despite the agronomic merit and economic significance of white clover, Australia lacks white clover cultivars that possess adaptive characteristics for persistence in mixed swards under sheep and cattle grazing. The major problem with contemporary white clover cultivars is that clover biomass fluctuates widely from year to year. This lack of reliability, particularly in dryland environments, is largely due to poor survival during summer moisture stress that is common to much of the Australian white clover zone. Factors such as edaphic constraints, intolerance of grass competition and close grazing, and lack of winter growth in cold environments also influence the contribution of white clover to pasture performance. This paper considers the mechanisms of regeneration, adaptive characteristics, and significance of white clover for animal production, and reflects on breeding objectives for white clover improvement.