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1
Bolland, M. D. A., and I. F. Guthridge. "Determining the fertiliser phosphorus requirements of intensively grazed dairy pastures in south-western Australia with or without adequate nitrogen fertiliser." Australian Journal of Experimental Agriculture 47, no. 7 (2007): 801. http://dx.doi.org/10.1071/ea05184.
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Fertiliser phosphorus (P) and, more recently, fertiliser nitrogen (N) are regularly applied to intensively grazed dairy pastures in south-western Australia. However, it is not known if applications of fertiliser N change pasture dry matter (DM) yield responses to applied fertiliser P. In three Western Australian field experiments (2000–04), six levels of P were applied to large plots with or without fertiliser N. The pastures were rotationally grazed. Grazing started when ryegrass plants had 2–3 leaves per tiller. Plots were grazed in common with the lactating dairy herd in the 6-h period between the morning and afternoon milking. A pasture DM yield response to applied N occurred for all harvests in all three experiments. For the two experiments on P deficient soil, pasture DM yield responses also occurred to applications of P. For some harvests when no fertiliser N was applied, probably because mineral N in soil was so small, there was a small, non-significant pasture DM response to applied P and the P × N interaction was highly significant (P < 0.001). However, for most harvests there was a significant pasture DM response to both applied N and P, and the P × N interaction was significant (P < 0.05–0.01), with the response to applied P, and maximum yield plateaus to applied P, being smaller when no N was applied. Despite this, for the significant pasture DM responses to applied P, the level of applied P required to produce 90% of the maximum pasture DM yield was mostly similar with or without applied N. Evidently for P deficient soils in the region, pasture DM responses to applied fertiliser P are smaller or may fail to occur unless fertiliser N is also applied. In a third experiment, where the soil had a high P status (i.e. more typical of most dairy farms in the region), there was only a pasture DM yield response to applied fertiliser N. We recommend that fertiliser P should not be applied to dairy pastures in the region until soil testing indicates likely deficiency, to avoid developing unproductive, unprofitable large surpluses of P in soil, and reduce the likelihood of P leaching and polluting water in the many drains and waterways in the region. For all three experiments, critical Colwell soil test P (a soil test value that was related to 90% of the maximum pasture DM yield), was similar for the two fertiliser N treatments.
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Holst, P. J., D. F. Stanley, G. D. Millar, A. Radburn, D. L. Michalk, P. M. Dowling, R. Van de Ven, et al. "Sustainable grazing systems for the Central Tablelands of New South Wales. 3. Animal production response to pasture type and management." Australian Journal of Experimental Agriculture 46, no. 4 (2006): 471. http://dx.doi.org/10.1071/ea04041.
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The main limitations for prime lamb production in the Central Tablelands of New South Wales are low availability of forage early in the growing season (late autumn–early winter) and low nutritive value in the summer. This paper describes the performance of a first-cross lamb breeding enterprise on 4 pasture types and 2 management systems over 4 years for the Central Tablelands region. The pastures studied comprised a traditional unfertilised naturalised pasture, a similar pasture fertilised with superphosphate, a sod-sown fertilised introduced perennial grass pasture and a sod-sown summer growing perennial, chicory (Cichorium intybus L.) pasture. Grazing management involved either continuous grazing or tactical grazing that combined a lower annual stocking rate with an optional summer rest to maintain perennial grass content above 50%. An additional area of chicory pasture was set aside for finishing lambs. Over the experiment stocking rates were increased each year as the pasture became established, with increases ranging from 1.5 ewes/ha for tactically grazed unfertilised natural pasture to 3.6 ewes/ha, for chicory and clover pasture. The feed quality v. quantity problem of summer and autumn was reaffirmed for each pasture type except chicory and the lamb enterprise appeared to be sufficiently adaptable to be promising. Ewes lambed in September and produced satisfactory lamb growth rates (about 280 g/day for twins) on the various pastures until weaning in late December. Thereafter, lamb growth rates declined as the pastures senesced, except chicory, reaffirming the feed quality v. quantity problem in summer and autumn of naturalised and sown grass pastures for producing lamb to heavyweight market specifications. Weaning liveweights (in the range of 32–40 kg) from grass-based pastures were high enough for only about 45% of the lambs to be sold as domestic trade lambs with the remainder as unfinished lambs. In contrast, the chicory and clover finishing pasture produced lamb growth rates of 125 g/day and quality large, lean lambs suitable for the export market. Vegetable matter in the late January shorn wool was insignificant and there was no significant effect of pasture on fleece weight, fibre diameter or staple strength. Position of break in staples of wool from chicory pastures differed from that of the other pasture types and warrants further study on time of shearing. It was concluded that a first cross lamb producing enterprise of suitable genetics was effective in producing trade and store lambs before pasture senescence, but the inclusion of a specialised pasture of summer growing chicory would create greater opportunities. In the unreliable summer rainfall region of the Central Tablelands, the area of chicory pasture needed to maintain lamb growth rates of >125 g/day, estimated from these results, is around 10 lamb/ha of chicory.
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Saul, Geoffrey, Gavin Kearney, and Dion Borg. "Pasture systems to improve productivity of sheep in south-western Victoria. 1. Growth, composition, nutritive value and persistence of resown pastures." Animal Production Science 49, no. 8 (2009): 654. http://dx.doi.org/10.1071/ea06142.
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Two pasture systems were compared at five on-farm sites across south-western Victoria between 1990 and 1996. The ‘typical’ pasture treatment mimicked the pasture and grazing management common in the region, with volunteer annual-based pastures fertilised with around 5 kg/ha phosphorus (P) each year. The ‘upgraded’ pasture treatments were resown to phalaris, perennial ryegrass and subterranean clover, and higher rates of fertiliser (13–25 kg P/ha.year) plus other nutrients were applied. Both pastures were set stocked with the participating farmers breeding ewes. Stocking rate was an emergent variable on each plot. The stocking rate on the typical treatments was based on normal farm practise. Initially, the stocking rate of the upgraded pastures was 15% higher than for the typical pastures and increased over time depending if the ewes in the upgraded pastures were heavier than those in the typical pastures. Measurements included soil fertility, pasture production, nutritive value and composition, and animal production. Net annual pasture production of the upgraded pastures was 10 500 kg/ha compared with 8700 kg/ha for the typical pastures. This average difference (18%) between the treatments was greatly influenced by the large advantage (40%) of the upgraded pasture in the wet year of 1992. Upgraded pastures had higher pasture production than typical pastures in spring but the reverse occurred in autumn. In a separate small plot experiment, the response of each pasture to higher P fertiliser applications was tested. In autumn and winter, there was a significant interaction between pasture type and P rate, with higher responses on the upgraded pastures. In spring, both pastures responded to increased P applications but the upgraded pastures were more responsive at all P rates. The upgraded pastures contained significantly higher legume content (30–50%) than the typical pastures (10–20%). The proportion of sown perennial grasses in the upgraded pasture declined from around 30 to 10% after 6 years displaced by annual grasses and broad-leaf weeds. Herbage from upgraded pastures had significantly higher crude protein content (2–7 units) and digestibility (1–10 units) than the typical pastures with the difference between the treatments increasing over time. The set stocking policy used in this experiment is likely to have exacerbated the decline in sown perennial grasses and implementation of some form of strategic or rotational grazing may have improved persistence. The experiment also highlights the importance of selecting perennial grasses able to cope with the local environment and grazing conditions. Despite the decline in perennials, these results show significant potential to improve pasture productivity and quality in south-western Victoria.
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Macdonald, K. A., C. Matthew, C. B. Glassey, and N. Mclean. "Dairy farm systems to aid persistence." NZGA: Research and Practice Series 15 (January 1, 2011): 199–209. http://dx.doi.org/10.33584/rps.15.2011.3199.
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This manuscript reviews fundamental pasture management principles relevant to pasture persistence. We first note some points of context, within which the debate on pasture persistence is occurring: the release of new pasture cultivars, the debate about climate change, and the effects of newly introduced weeds and pests. We then examine trends in farm practice. The critical management period (of most concern to farmers) has shifted from winter/autumn to summer. It is essential that farmers have and use sets of decision rules to govern when and how hard to graze, when to supplement and when to remove cows from pasture to allow pastures to be grazed appropriately to aid pasture persistence. Adaptations available to improve pasture persistence include: the use of nitrogen fertiliser to increase feed supply going into the summer, the use of crops or other feed supplements, stocking rate and on-off grazing to ensure the pastures are appropriately grazed in the summer. New pastures must be treated with care in their first year of life to ensure survival. The response of farmers to these variables to aid persistence of pastures is discussed. Keywords: climate, insect pests, pasture growth model, pasture renewal, weeds
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Bolland, M. D. A., and I. F. Guthridge. "Quantifying pasture dry matter responses to applications of potassium fertiliser for an intensively grazed, rain-fed dairy pasture in south-western Australia with or without adequate nitrogen fertiliser." Animal Production Science 49, no. 2 (2009): 121. http://dx.doi.org/10.1071/ea08106.
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Rain-fed dairy pastures on sandy soils common in the high rainfall (>800 mm annual average) Mediterranean-type climate of south-western Australia comprise the annual species subterranean clover (Trifolium subterraneum L.) and annual and Italian ryegrass (Lolium rigidum Gaud. and L. multiflorum Lam.). In wet years, clover becomes potassium (K) deficient and shows large dry matter (DM) responses to applied fertiliser K due to leaching of K in soil by rainfall. In contrast, ryegrass rarely shows DM responses to applied K. Many dairy pastures in the region are now intensively grazed to maximise pasture use for milk production, and nitrogen (N) fertiliser is applied after each grazing. It is not known if frequent applications of fertiliser N to these pastures changes pasture DM responses to applied K. Therefore, a long-term (2002–07) field experiment was undertaken on an intensively grazed dairy pasture in the region to quantify pasture DM responses to applied fertiliser K with or without applications of adequate fertiliser N (141–200 kg N/ha per year). Soil samples (top 10 cm of soil) were collected from each plot of the experiment each February to measure soil test K by the standard Colwell sodium bicarbonate procedure used for both K and phosphorus soil testing in the region. When no N was applied, pasture comprised ~70% (dry weight basis) clover and 25% ryegrass, compared with ~70% ryegrass and 25% clover when adequate N was applied. Significant linear responses of pasture DM to applied K occurred in 3 of the 6 years of the experiment only when no N was applied and clover dominated the pasture. The largest response varied from ~1.7 to 2.0 t/ha DM consumed by dairy cows at all grazings in each year, giving a K response efficiency of between 8 and 10 kg DM/ha per kg K/ha applied. Significant pasture DM responses to applied N occurred at all grazings in each year, with ~2–3 t/ha extra DM consumed by dairy cows at all grazings in each year being produced when a total of 141–200 kg N/ha was applied per year, giving an N response efficiency of ~7–19 kg DM/ha per kg N/ha applied. Soil test K values were very variable, attributed to varying proportions of soil samples per plot collected between and within cow urine patches, containing much K, arbitrarily deposited on experimental plots during grazing. Soil test K values were not significantly affected by the rates of K applied per year. A re-evaluation of results from the major soil K test study conducted for pastures in the region confirm that ryegrass rarely showed DM responses to applied K, and that for clover, soil K testing poorly predicted the likelihood of K deficiency in the next growing season.
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Gourley, C. J. P., and G. S. James. "Predicting the response of irrigated perennial pasture to superphosphate in Victoria." Soil Research 35, no. 2 (1997): 301. http://dx.doi.org/10.1071/s96061.
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Experiments were conducted at 42 sites in the northern and south-eastern irrigation districts of Victoria to determine the relationship between extractable phosphorus (P) using the Olsen P soil test, and response of irrigated perennial pasture to an annual application of superphosphate. Relative responses (the response relative to the maximum yield, P non-limiting) were measured over 4 seasons (summer, autumn, winter, and spring). At 12 of these sites, selected from a range of soils with different clay contents, the effect of clay content on the curvature of the pasture dry mass (DM) response was determined. Different soil-sampling methods, with the surface organic mat included or excluded from the sample, were used to measure Olsen P. A well-defined linear model described the relationship between Olsen P values of soil sampled using these two methods. There was no significant effect of season on the relationship between relative response and Olsen P value. There was also no significant relationship between the curvature of the response to applied P and clay content of the soil. The derived relationship between Olsen P soil test level and relative response to applied fertiliser accounted for only 14 · 6% of the variation and it appears that other factors are markedly affecting irrigated pasture response to applied superphosphate. The accumulation of organic matter on the surface of irrigated perennial pastures may be influencing nutrient availability and pasture growth, and warrants further investigation.
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Gourley, Cameron J. P., Murray C. Hannah, and Kohleth T. H. Chia. "Predicting pasture yield response to nitrogenous fertiliser in Australia using a meta-analysis-derived model, with field validation." Soil Research 55, no. 6 (2017): 567. http://dx.doi.org/10.1071/sr17032.
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An improved ability to predict pasture dry matter (DM) yield response to applied nitrogen (N) is a crucial step in determining the production and economic benefits of N fertiliser inputs with associated environmental benefits from reducing inefficient N fertiliser use. Pasture DM yield responses to applied N fertiliser from 920 independent field trial sites were used from a database repository of Australian fertiliser experiments. These data were analysed and a quantitative non-linear mixed-effects model based on the Mitscherlich function was developed. The fitted model provided a good fit to a large body of data (R2 = 0.92), using readily interpretable coefficients, including fixed effects for state by season, phosphorus status and harvest type (initial or residual), and nested random effects for location and trial or subtrial. The model was limited by patchiness of metadata, uneven representation of regions and few very high rates of applied N in the data. Nonetheless, model predictions were comparable with independent spring pasture DM responses to applied N fertiliser from subsequent field studies on three contrasting pastures on commercial dairy farms in Victoria. The final derived model can be used to predict pasture yield response to applied N fertiliser as a proportion of obtainable yield and can be scaled to absolute response using the fitted model estimates of maximal yield or, more usefully, a specified maximal yield by the user. Importantly, the response function exhibits diminishing returns, enabling marginal economic analysis and determination of optimum N fertiliser application rate to a specified pasture.
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Gourley, Cameron J. P., David M. Weaver, Richard J. Simpson, Sharon R. Aarons, Murray M. Hannah, and Ken I. Peverill. "The development and application of functions describing pasture yield responses to phosphorus, potassium and sulfur in Australia using meta-data analysis and derived soil-test calibration relationships." Crop and Pasture Science 70, no. 12 (2019): 1065. http://dx.doi.org/10.1071/cp19068.
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An improved ability to predict pasture dry matter (DM) yield response to applied phosphorus (P), potassium (K) and sulfur (S) is a crucial step in determining the production and economic benefits of fertiliser inputs and the environmental benefits associated with efficient nutrient use. The adoption and application of soil testing can make substantial improvements to nutrient use efficiency, but soil test interpretation needs to be based on the best available and most relevant experimental data. This paper reports on the development of improved national and regionally specific soil test–pasture yield response functions and critical soil test P, K and S values for near-maximum growth of improved pastures across Australia. A comprehensive dataset of pasture yield responses to fertiliser applications was collated from field experiments conducted in all improved pasture regions of Australia. The Better Fertiliser Decisions for Pastures (BFDP) database contains data from 3032 experiment sites, 21918 yield response measures and 5548 experiment site years. These data were converted to standard measurement units and compiled within a specifically designed relational database, where the data could be explored and interpreted. Key data included soil and site descriptions, pasture type, fertiliser type and rate, nutrient application rate, DM yield measures and soil test results (i.e. Olsen P, Colwell P, P buffering, Colwell K, Skene K, exchangeable K, CPC S, KCl S). These data were analysed, and quantitative non-linear mixed effects models based upon the Mitscherlich function were developed. Where appropriate, disparate datasets were integrated to derive the most appropriate response relationships for different soil texture and P buffering index classes, as well as interpretation at the regional, state, and national scale. Overall, the fitted models provided a good fit to the large body of data, using readily interpretable coefficients, but were at times limited by patchiness of meta-data and uneven representation of different soil types and regions. The models provided improved predictions of relative pasture yield response to soil nutrient status and can be scaled to absolute yield using a specified maximal yield by the user. Importantly, the response function exhibits diminishing returns, enabling marginal economic analysis and determination of optimum fertiliser application rate to a specific situation. These derived relationships form the basis of national standards for soil test interpretation and fertiliser recommendations for Australian pastures and grazing industries, and are incorporated within the major Australian fertiliser company decision support systems. However, the utility of the national database is limited without a contemporary web-based interface, like that developed for the Better Fertiliser Decisions for Cropping (BFDC) national database. An integrated approach between the BFDP and the BFDC would facilitate the interrogation of the database by advisors and farmers to generate yield response curves relevant to the region and/or pasture system of interest and provides the capacity to accommodate new data in the future.
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Elliott, D. E., and R. J. Abbott. "Nitrogen fertiliser use on rain-fed pasture in the Mt Lofty Ranges, SouthAustralia. 2. Responses of perennial grasses, Tama ryegrass, andsod-sown oats to nitrogen fertiliser and cutting frequency." Australian Journal of Experimental Agriculture 43, no. 6 (2003): 579. http://dx.doi.org/10.1071/ea01132.
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Two series of experiments were conducted in the Mt Lofty Ranges, South Australia, to examine, in a grass–subterranean clover pasture, the contribution of the companion grass to herbage mass and the responsiveness to the application of nitrogen (N) fertiliser. The first study examined the responsiveness, to a single rate of N, of grass–clover pastures containing either Tama ryegrass, sod-sown oats or 1 of 4 perennial grasses, viz. Victorian perennial ryegrass, Demeter fescue, Currie cocksfoot or Australian phalaris. These were compared in 2 experiments, under 3��different cutting frequencies at 3 periods during the growing season. In the other study, consisting of 12�experiments, the response to increasing rate of N fertiliser application of sod-sown oats or the existing pasture were compared over a 3-month period following N fertiliser application in autumn.In autumn and winter, all pastures responded significantly to N fertiliser, whereas in spring, the proportion of clover in each pasture and its growth determined whether or not there was a response to N fertiliser. Clover composition of pastures declined with N application, but clover was not eliminated from swards by application of 210 kg N/ha a year. In both series of experiments, pastures that established well with a high density of sod-sown oats out-yielded all other pastures in autumn and winter, whether the swards were unfertilised or received regular N fertiliser applications. In late winter, pastures sod-sown with Tama ryegrass yielded as well as the pasture sod-sown with oats, and enhanced spring growth significantly compared with perennial ryegrass. However, spring production of Tama ryegrass was poorer than that of perennial ryegrass, and overall no increase in annual production occurred. Of the perennial grasses, the highest yielding when N fertiliser was applied were Currie cocksfoot and perennial ryegrass (yielding in autumn), phalaris (winter), and perennial ryegrass and Demeter fescue (spring). Increased cutting frequency depressed the herbage mass response to N fertiliser following the initial application, but increased herbage N concentration of all pastures and also increased the final clover composition of N-fertilised pasture of 4�pasture types.
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Toscan, Gustavo, Gustavo Cauduro Cadore, João Francisco Tadinello Limana, Augusto Weber, Heloisa Heinloft Palma, Marta Medeiros Frescura Duarte, Luis Antônio Sangioni, and Fernanda Silveira Flores Vogel. "Immune response of sheep naturally infected with Haemonchus spp. on pastures with two different nutritional conditions." Semina: Ciências Agrárias 38, no. 2 (May 2, 2017): 809. http://dx.doi.org/10.5433/1679-0359.2017v38n2p809.
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Parasitic nematodes in the gastrointestinal tract of small ruminants are considered one of the main causes of economical and productive losses. Haemonchus contortus is characterized as the major parasite affecting sheep worldwide. This study was designed to evaluate immunological responses in sheep naturally infected with Haemonchus spp. in two different feed grounds: native and cultivated pasture. Fecal and blood samples were collected weekly from fifteen Corriedale sheep, ages 8 to 12 months, to determine the counting of eggs per gram of feces (EPG), and the concentration of haematocrit, eosinophils, and cytokines during an 84-day experiment. Bromatological analysis of the two pasture treatments (types) showed levels of crude protein and non-fibrous carbohydrates of 9.7% and 12.3% in the native pasture and 14.3% and 23.7% for the cultivated pasture, respectively. No significant difference in haematocrit concentration was found during the experiment between different pastures (p < 0.05). However, significant differences were found in EPG, eosinophils, interleukins, and immunoglobulins levels after 21 days in the cultivated (nutritionally-enhanced) pasture. These data suggest that immune response was characterized in sheep by significantly higher peripheral eosinophilia and an increase in serum concentrations of IgE, IgA, IgG, TNF-?, IFN-?, and IL-6. Likewise, the improvement in forage condition resulted in a reduction of EPG and an increase of elements that improve a sheep’s immune system response against Haemonchus spp. infection.
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Robertson, G. "Effect of drought and high summer rainfall on biomass and comsumption of grazed pastures in western New South Wales." Rangeland Journal 9, no. 2 (1987): 79. http://dx.doi.org/10.1071/rj9870079.
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The biomass and composition of grazed pastures near Menindee, in westem New South wales, were estimated over a range of seasonal condilions between 1980 and 1985. Differences in biomass and composition of pastures grazed separately by kangaroos and by a mixture of sheep and kangaroos were minor. Pasture biomass ranged from 7 kgha during a drought to 1,100 kgha following high summer rainfall. Overall, biomass average 374 kgha with a slandard deviation among years of 302 kgha. Pasture biomass fluctuated markedly among calendar seasons and years in response to erratic rainfall and grazing. I-Iigh summer rainfall triggered a switch in pasture dominatnace from annuals to shoa-lived perennials.
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Brazendale, R., J. R. Bryant, M. G. Lambert, C. W. Holmes, and T. J. Fraser. "Pasture persistence: how much is it worth?" NZGA: Research and Practice Series 15 (January 1, 2011): 3–6. http://dx.doi.org/10.33584/rps.15.2011.3213.
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The farm system model, Farmax Dairy Pro, was used to evaluate the impact of new pastures on dairy farm profitability, assuming a range of pasture yields and qualities, and different levels of persistence in the new pastures, which were established on 10% of the farm annually. Scenarios were tested for Waikato, Taranaki, Canterbury and Southland dairy farm systems. Assuming a $6.50/kg MS milk payment and a response to pasture renewal of 10% in dry matter yield and a 0.6 MJ ME/kg DM increase in quality, increasing persistence from 4 years up to 8 years was modelled to increase dairy farm profitability by $271/ha to $478/ha. Management practices, including selections of cultivars and endophytes, that improve pasture persistence are likely to increase dairy farm profitability. Keywords: dairy farms, modelling, pasture renewal, persistence
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Grekul, Chad W., and Edward W. Bork. "Herbage Yield Losses in Perennial Pasture Due to Canada Thistle (Cirsium arvense)." Weed Technology 18, no. 3 (September 2004): 784–94. http://dx.doi.org/10.1614/wt-03-196r.
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Although the impact of Canada thistle (CT) on annual crop production is relatively well established, few investigations report on this weed's impact within perennial pastures. This field study assessed herbage yield losses within eight central Alberta pastures from 1999 to 2001. Each pasture was sampled in 1999 to quantify thistle and herbage biomass within 25 permanent plots. CT was controlled in 2000 and the response of vegetation measured in 2000 and 2001. Before removal, significant negative relationships (P < 0.05) between thistle abundance and herbage were noted at six sites. After thistle removal, herbage at several sites displayed positive responses. Both thistle density and biomass adequately predicted herbage yield loss. Yield losses due to CT can be substantial, peaking at 2 kg/ha for each kilogram of standing thistle biomass and 4.3 kg/ha with each additional thistle stem per square meter. Demonstrated yield losses were variable among sites however, likely due to factors such as heterogeneity in soils, available moisture, and variation in disturbance history or pasture vegetation composition. CT management in perennial pastures of western Canada may enhance pasture production, but further research is required to reliably predict the ability of pastures to respond.
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Stevens, D. R., and I. D. Corson. "Effects of fresh forage quality on feed intake and live weight gain of red deer in spring." Journal of New Zealand Grasslands 77 (January 1, 2015): 95–102. http://dx.doi.org/10.33584/jnzg.2015.77.495.
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Changes in voluntary feed intake (VFI) and average daily gain (ADG) of 10- to 12-month-old male red deer (Cervus elaphus) in response to a range of pasture morphological development stages of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) pasture in spring were investigated. An intake study in November 2000 tested responses to pastures spelled for 6, 8 or 10 weeks in a combined indoor/outdoor comparison over two weeks. This was followed by a 5 week grazing study which compared 3, 5 or 7 week spelling periods during November and December in 2001. Pasture spelled for 6, 8 or 10 weeks had acid detergent fibre concentrations of 216, 229 and 252 g/kg DM (P
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Cowan, RT, KF Lowe, PC Upton, and TM Bowdler. "Nitrogen-fertilised grass in a subtropical dairy system 3. Effect of stocking rate on the response to nitrogen fertiliser." Australian Journal of Experimental Agriculture 35, no. 2 (1995): 145. http://dx.doi.org/10.1071/ea9950145.
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Two stocking rates, one as practised on farms (2 cows/ha) and the other 50% higher, were assessed for effect on pasture and milk yield response to applied nitrogen (N) fertiliser (0-600 kg N/ha. year) for Holstein-~Friesian cows grazing Rhodes grass (Chloris gayana) cv. Callide pastures. Pastures were grazed in combination with grazing oats for winter, with overall farm stocking rates of 1.17 and 1.37 cows/ha for ' the 2 treatments. Cows were maintained on these areas for 3 years. Cracked grain was given at 0.8 t/cow. year, and hay or silage supplements were given when green grass yield was <0.5 t dry matter (DM)/ha. The incremental response (P<0.05) in milk yield to each kg increase in level of applied N was 4.93 kg/ha at 1.17 cows/ha and 1.64 kg/ha at 1.37 cows/ha. The amount of conserved forage fed at the high stocking rate increased (530 and 970 kg/ha. year at 1.17 and 1.37 cows/ha), and financial margins over costs were reduced at the high stocking rate. The low milk response at the high stocking rate was associated with a low response in pasture growth. At <2 t pasture DM/ha on offer, incremental response to applied N declined, and there may have been an excessive loss of N through volatilisation in heavily grazed pastures. Milk yield per cow was closely related to total pasture yield on offer (P<0.01), and to leaf and stem yields (P<0.05). Relationships were stronger in summer and autumn than in spring. Over the full year, milk yield increased by 1.24 kg/kg leaf DM or 0.24 kg/kg total pasture DM on offer. At the higher stocking rate, surface soil (0-10 cm) concentrations of phosphorus and nitrate were higher than at the lower stocking rate. We conclude that in areas of moderate rainfall (<1000 mm/year) in the subtropics, high stocking rates resulting in low pasture yields and exposed ground surface will be associated with low efficiency of use of applied N.
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CHEN, G., G. D. LI, M. K. CONYERS, and B. R. CULLIS. "LONG-TERM LIMING REGIME INCREASES PRIME LAMB PRODUCTION ON ACID SOILS." Experimental Agriculture 45, no. 2 (April 2009): 221–34. http://dx.doi.org/10.1017/s0014479708007497.
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SUMMARYPrime lamb live weight response to lime application on pasture was measured in a grazing experiment in the high rainfall zone of the southwestern slopes of New South Wales, Australia. The pastures were limed every 6 years over 15 years. First cross South African Meat Merino lambs were used as test animals. Pre- and post-grazing pasture dry matter (DM) yield, botanical composition, feed quality and lamb live weight were monitored over 12 weeks in 2007. Results showed that liming significantly increased pasture DM yield of high quality species and improved overall pasture quality due to increased digestibility and metabolic energy content. As a result, the limed perennial and annual pastures carried 24.0% (3.6 lambs ha−1) and 29.0% (4.4 lambs ha−1) more stock than the unlimed perennial and annual pastures, respectively. Averaged across pasture types, the limed pastures produced 30.6% (131 kg ha−1) more lamb live weight gain than the unlimed pastures over 12 weeks. The live weight gain varied between grazing cycles depending on the availability of feed-on-offer and feed quality, which were closely related to the rainfall pattern. The perennial pastures did not show any advantage in animal production over annual pastures during the experimental period due to lack of moisture in the deep soil profile because of severe drought in the previous year. More seasons with normal or above average rainfall are needed to compare animal production on perennial pastures and annual pastures to investigate the advantage of perennial pastures in animal production.
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Shakhane, L. M., C. Mulcahy, J. M. Scott, G. N. Hinch, G. E. Donald, and D. F. Mackay. "Pasture herbage mass, quality and growth in response to three whole-farmlet management systems." Animal Production Science 53, no. 8 (2013): 685. http://dx.doi.org/10.1071/an12262.
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The effects of different whole-farm management systems were explored in a farmlet trial on the Northern Tablelands of New South Wales, Australia, between July 2000 and December 2006. The three systems examined were first, a moderate input farmlet with flexible grazing on eight paddocks considered ‘typical’ of the region (farmlet B), a second, also with flexible grazing on eight paddocks but with a high level of pasture renovation and increased soil fertility (farmlet A) and a third with the same moderate level of inputs as farmlet B but which practised intensive rotational grazing on 37 paddocks (farmlet C). The changes in herbage mass, herbage quality and pasture growth followed a seasonal pattern typical of the Northern Tablelands with generally higher levels recorded over spring–summer and lower levels in autumn–winter but with substantial differences between years due to the variable climate experienced. Over the first 18 months of the trial there were no significant differences between farmlets in total herbage mass. Although the climate was generally drier than average, the differences between farmlets in pasture herbage mass and quality became more evident over the duration of the experiment. After the farmlet treatments started to take effect, the levels of total and dead herbage mass became significantly lower on farmlet A compared with farmlets B and C. In contrast, the levels of green herbage were similar for all farmlets. Throughout most of the study period, pastures on farmlet A with its higher levels of pasture renovation and soil fertility, had significantly higher DM digestibility for both green and dead herbage components compared with pastures on either of the moderate input systems (B and C). Thus, when green herbage mass and quality were combined, farmlet A tended to have higher levels of green digestible herbage than either of the other farmlets, which had similar levels, suggesting that pasture renovation and soil fertility had more effect on the supply of quality pasture than did grazing management. This difference was observed in spite of the higher stocking rate supported by farmlet A after treatments took effect. Levels of legume herbage mass, while generally low due to the dry conditions, were significantly higher on farmlet A compared with the other two farmlets. While ground cover on farmlet A was found to be less than the other farmlets, this was largely associated with the higher level of pasture renovation. Generally, all three farmlets had ground cover levels well above 70% for the duration of the experiment, thus being above levels considered critical for prevention of erosion. A multivariate analysis showed that the main explanatory factors significantly linked (P < 0.01) with the supply of high quality herbage were, in decreasing order of importance, those related to season and weather, pasture renovation, grazing management and soil fertility. Measurements of net pasture growth conducted using a limited number of grazing exclosure cages on three paddocks per farmlet revealed clear seasonal trends but no significant (P > 0.05) differences between farmlets. However, post hoc estimates of potential pasture growth rate using remotely sensed MODIS satellite images of normalised difference vegetation index captured weekly from each farmlet revealed a significant (P < 0.001) relationship with the seasonal pattern observed in the measurements of pasture growth rate.
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Parish, Roberta, and Roy Turkington. "The influence of dung pats and molehills on pasture composition." Canadian Journal of Botany 68, no. 8 (August 1, 1990): 1698–705. http://dx.doi.org/10.1139/b90-218.
Full textAbstract:
The abundance and distribution of plant species, molehills, and dung pats were surveyed on eight occasions over 26 months in three adjacent pastures of different age. There were few features related to pasture age, but each pasture had a different disturbance regime. Dung deposition and molehill distribution usually fitted Poisson and negative binomial distributions, respectively. The abundance of some species responded to current disturbances, e.g., Trifolium repens, and others to disturbances in the previous season, e.g., Lolium perenne. Holcus lanatus abundance declined in areas of high disturbance, whereas Dactylis glomerata, Agropyron repens, and Taraxacum officinale abundance increased. The response patterns of these species are discussed in the context of season, year, pasture age, and type of disturbance. Key words: disturbance, dung, molehill, pastures.
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Latta, R. A., and A. Lyons. "The performance of lucerne - wheat rotations on Western Australian duplex soils." Australian Journal of Agricultural Research 57, no. 3 (2006): 335. http://dx.doi.org/10.1071/ar04016.
Full textAbstract:
In field experiments on duplex soils in the south-eastern and central Western Australian wheatbelt, lucerne (Medicago sativa L.) was compared with subterranean clover (Trifolium subterraneum L.) in pasture–crop rotations. Comparative pasture plant densities and biomass, soil water content, available soil nitrogen, wheat grain yield, and protein content were measured during 2 and 3 years of pasture followed by 2 and 1 year of wheat, respectively. Lucerne densities declined by 60–90% over the 3-year pasture phase but produced up to 3 times more total annual biomass than weed-dominant annual pastures and similar total annual biomass when annual pastures were legume dominant. Lower soil water contents were measured under lucerne than under annual pastures from 6 months after establishment, with deficits up to 60 mm in the 0–1.6 m soil profile. However, significant rain events and volunteer perennial weeds periodically negated comparative deficits. Wheat yields were lower following lucerne (1.3 t/ha) than following an annual pasture (1.8 t/ha) in a low-rainfall season, higher (3.7 v. 2.9 t/ha) in a high-rainfall season, and much higher when the previous annual pastures were grass dominant (3.4 v. 1.5 t/ha). Grain protein contents were 1–2% higher in response to the lucerne pasture phase. Overcropping wheat into a lucerne pasture of 19 plants/m2 reduced wheat grain yields, but a lucerne density of 4 plants/m2 reduced yields only where rainfall was low. The study has shown that lucerne–wheat rotations provide a productive farming system option on duplex, sodic soils in both the south-eastern and central cropping regions of Western Australia. This was most evident in seasons of above-average summer and growing-season rainfall and when compared with grass-dominant annual pastures.
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Alemu, Aklilu, Roland Kröbel, Brian McConkey, and Alan Iwaasa. "Effect of Increasing Species Diversity and Grazing Management on Pasture Productivity, Animal Performance, and Soil Carbon Sequestration of Re-Established Pasture in Canadian Prairie." Animals 9, no. 4 (March 29, 2019): 127. http://dx.doi.org/10.3390/ani9040127.
Full textAbstract:
The objective of the study was to determine the effect of type of pasture mix and grazing management on pasture productivity, animal response and soil organic carbon (SOC) level. Pasture was established in 2001 on 16 paddocks of 2.1 ha that had been primarily in wheat and summer fallow. Treatments consisted of a completely randomized experimental design with two replicates: two pasture mixes (7-species (7-mix) and 12-species (12-mix)) and two grazing systems (continuous grazing (CG) and deferred-rotational grazing (DRG)). Pasture was stocked with commercial yearling Angus steers (Bos Taurus, 354 ± 13 kg) between 2005 and 2014. All pastures were grazed to an average utilization rate of 50% (40% to 60%). Average peak and pre-grazing pasture dry matter (DM) yield and animal response were independent of pasture seed mixture but varied with grazing management and production year. Average peak DM yield was 26.4% higher (p = 0.0003) for pasture under DRG relative to CG (1301 kg ha−1). However, total digestible nutrient for pasture under DRG was 4% lower (p < 0.0001) as compared to CG (60.2%). Average daily weight gain was 18% higher (p = 0.017) for CG than DRG (0.81 kg d−1), likely related to higher pasture quality under CG. Soil carbon sequestration was affected by seed mixture × grazing system interaction (p ≤ 0.004). Over the fourteen years of production, pasture with 7-mix under CG had the lowest (p < 0.01) average SOC stock at 15 cm (24.5 mg ha−1) and 30 cm depth (42.3 mg ha−1). Overall, the results from our study implied that increasing species diversity for pasture managed under CG may increase SOC gain while improving animal productivity.
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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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Calvano, Maria Paula Cavuto Abrão, Valéria Pacheco Batista Euclides, Denise Baptaglin Montagner, Beatriz Lempp, Gelson dos Santos Difante, Renata Santos Flores, and Sandra Galbeiro. "Tillering and forage accumulation in Marandu grass under different grazing intensities." Revista Ceres 58, no. 6 (December 2011): 781–89. http://dx.doi.org/10.1590/s0034-737x2011000600015.
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Studies of plant responses to defoliation are important to develop pasture management strategies. The objective of this study was to evaluate the population density of basal, aerial and reproductive tillers, tiller appearance and mortality rates, forage accumulation and sward structure in Marandu grass pastures under different grazing intensities. The experimental period was from January to June 2006, divided in three seasons: summer, autumn and winter. The pastures were continuously grazed using variable stocking rates. The grazing intensities corresponded to 15, 30 and 45 cm of sward height. The experiment was arranged in a complete randomized block design with three treatments and two replicates. The sward heights were measured twice a week. The response variables were: forage accumulation, forage mass and its morphological components; and population densities of basal (TPDb), aerial (TPDa) and reproductive (TPDr) tillers. The highest TPDb (P > 0.05) was recorded for the shortest sward pasture, and the highest TPDr (P<0.05) for the tallest sward pasture. Swards showed a tiller size/density compensation mechanism and, consequently, the forage accumulation was similar (P > 0.05) among the grazing intensities. Pasture with a sward height of 35 cm had 94% of sun light interception. The highest variations in forage accumulation and sward structure were more influenced by seasonal differences than by grazing intensities. Pastures of Marandu grass showed large flexibility in grazing management, which allowed it to be maintained at sward heights between 15 and 35 cm.
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McCartney, D. H., S. Bittman, P. R. Horton, J. Waddington, and W. F. Nuttall. "Uptake of N, P and S in fertilized pasture herbage and herbage yield response to fertilizer as affected by soil nutrients." Canadian Journal of Soil Science 78, no. 1 (February 1, 1998): 241–47. http://dx.doi.org/10.4141/s97-007.
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Uptake of N, P and S nutrients in the herbage of different pasture species were determined at eight sites within pastures located on Luvisolic soils in northeastern Saskatchewan, Canada. Also, the nutrient status of the soil was related to herbage yield response to N, P and S fertilizers. Soil tests would be used to establish the initial response to ferilizer and thereafter, nutrients removed from the soil could be replaced by fertilizer. Experiments in the study included one site with bromegrass (Bromus inermis Leyss.) and alfalfa (Medicago media Pers.), six sites on a pasture mixture (Bromus inermis Leyss., Festuca rubra L., Poa pratensis L. and Medicago media Pers.) and one site with Russian wildrye (Psathyrostachys juncea (Fisch.) Nevski) at both Pathlow and Pleasantdale pastures. Nitrogen and P fertilizers were applied at 0, 45 and 90 kg N ha−1 in combination with P at 0 and 20 kg ha−1. Sulphur treatments included 90N–20P–2-S (sulphate source, kg S ha−1) on pasture mixture sites and two treatments of 90N–20P–23S and 90N–20P–45S (elemental source, kg S ha−1) on bromegrass and alfalfa. Maximum uptake of nutrients were 103.6 kg N, 11.5 kg P and 5.2 kg S ha−1 with the application of 90N–20P–45S (kg ha) on the bromegrass–alfalfa pasture. The controls resulted in the lowest uptake of 20.2 kg N, 1.9 kg P (pasture mixture) and 1.5 kg S ha−1 (bromegrass and alfalfa). Yield response to N and P fertilizers (percentage yield over control) was related to soil tests for N, P and S (r2 = 0.42). Herbage yield increase (log10 mean of years) from S fertilizer over the control was negatively related to the soil test for S on six sites (r2 = 0.77). Uptake of N, P and S in herbage gave an adequate estimate of nutrient removal and the amount of fertilizer to apply to maintain soil nutrient levels. Key words: pasture, N, P, S, herbage, soil tests, yield
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WALKER, R. G., T. M. DAVISON, W. N. ORR, and B. A. SILVER. "Phosphorus fertilizer for nitrogen-fertilized dairy pastures. 3. Milk responses to a dietary phosphorus supplement." Journal of Agricultural Science 129, no. 2 (September 1997): 233–36. http://dx.doi.org/10.1017/s0021859697004656.
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Dairy cows grazing a tropical grass pasture fertilized with 300 kg N/ha and with a 7-year history of phosphorus fertilizer at either 0 or 45 kg P/ha were given a P supplement in a 2 × 2 factorial experiment at Kairi Research Station, Queensland, Australia. Milk yield, fat-corrected milk yield, yields of milk fat, protein and lactose, and protein content of milk were increased (P<0·05) with P fertilizer. There was no response in milk yield or any component of milk to the provision of a P supplement. It is concluded that the milk response recorded in this experiment was due to P fertilizer leading to additional pasture on offer and increased pasture intake. The lack of response to additional P in the form of a supplement indicates that these pastures can supply adequate P for cows producing 20 kg/day even after 8 years without P fertilizer.
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Gillingham, A. G., G. W. Sheath, M. H. Gray, and R. W. Webby. "Management and nitrogen fertiliser options for increased pasture productivity in dryland hill systems." NZGA: Research and Practice Series 11 (January 1, 2003): 43–49. http://dx.doi.org/10.33584/rps.11.2003.3002.
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Legume productivity in dryland pastures is often less than 10% of the total annual growth and dominated by annual species. White clover content of these pastures is often less than 5% because the period of potentially most active growth coincides with that of low soil moisture levels. Therefore variations in summer rainfall have a dominant effect on the white clover content of the pasture in the following spring. Predictive relationships for white clover content are presented. Attempts to introduce alternative legumes into dryland hill pastures have generally been unsuccessful because of the harsh climate during late spring-summer and competition from resident species. It is unlikely that further research will change this situation. This paper compares improved legume productivity from dryland pastures with the use of N fertiliser as options to increase winter and spring pasture growth for increased economic gain. To optimise productivity and summer persistence of resident legumes, grazing management, especially in spring, must aim to avoid accumulation of surplus grass that will shade associated legumes. During winter and early spring, when soil moisture is adequate, pasture growth in dryland hill pastures is limited by inadequate soil nitrogen (N), due to low legume content and N fixation, even where soil phosphorus (P) is at moderate to high levels. Consequently, pasture responds well to applied N fertiliser. At Waipawa in Hawke's Bay, the magnitude of response to N fertiliser was inversely related to the legume content of the pasture and so was greatest (e.g. up to 47 kg DM/kg N) on steep north aspects with little clover, and much less (8-17 kg DM/kg N) on easy slopes. In winter, N fertiliser offers reliable and significant increases in pasture growth. To optimise economic returns from the additional pasture dry matter, winter stocking rates could be increased. However, a simulation study showed that the maximum economic benefit would be obtained by maintaining ewe numbers and increasing fecundity to produce more lambs. Key words: hill country, legumes, nitrogen fertiliser, pastoral dryland
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Leech, Fiona J., Alan E. Richardson, Michael A. Kertesz, Beverley A. Orchard, Samiran Banerjee, and Phillip Graham. "Comparative effect of alternative fertilisers on pasture production, soil properties and soil microbial community structure." Crop and Pasture Science 70, no. 12 (2019): 1110. http://dx.doi.org/10.1071/cp19018.
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Different fertiliser products are commonly promoted for use on pastures in order to improve pasture productivity and support a more ‘healthy’ soil microbial environment. However, minimal field research has been conducted to validate such claims. A 6-year study (2009–14) was conducted on phosphorus (P)-deficient soils at three sites near Yass, New South Wales, to investigate the effect of topdressing perennial native-based pastures with a range of alternative fertilisers compared with single superphosphate and an unfertilised control treatment. The alternative fertiliser products included manures, composts, crushed rock, rock-phosphate-derived products, concentrated ash and microbial products. Annual measurements were made of soil chemical properties, botanical composition and pasture yield during spring and/or winter + spring, as well as the relative effectiveness of products per unit of pasture grown. Soil microbial community structure under each fertiliser treatment was also analysed in the sixth year of the study. Fertiliser products with substantial quantities of P increased extractable soil P and resulted in significantly higher pasture growth and clover content compared with the unfertilised control. Superphosphate was found to be the most P-effective fertiliser for increasing pasture growth, along with a range of other products that showed differential responses. However, the cost and P-effectiveness of the products in relation to pasture growth varied considerably and was a function of rate and frequency of application as well as amount and solubility of the P applied. Despite large differences in pasture growth across the various fertiliser treatments, there was no significant effect of the alternative fertiliser products on microbial community structure compared with either the superphosphate or unfertilised control treatments. The observed variation in bacterial, fungal and archaeal community structures across all fertiliser treatments was best explained by soil pH or aluminium (Al) concentration, which was influenced differentially by the fertiliser products. Fungal community structure was also correlated with pasture-productivity parameters (i.e. spring pasture yield, clover content and soil-available P). Our findings reveal a highly resilient soil microbial community that was influenced minimally by use of the alternative fertiliser products, thus highlighting that on-farm management decisions regarding fertiliser product choice should primarily focus on pasture response and cost-effectiveness.
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DEL PINO, A., T. RODRÍGUEZ, and J. ANDIÓN. "Production improvement through phosphorus fertilization and legume introduction in grazed native pastures of Uruguay." Journal of Agricultural Science 154, no. 2 (November 3, 2015): 347–58. http://dx.doi.org/10.1017/s002185961500101x.
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SUMMARYThe objective of the current study was to quantify the response of pasture to phosphorus (P) fertilizer application and legume introduction, by measuring herbage yield, nitrogen (N) and P content, and weight gain of calves in native pastures of Uruguay. Quantitative relationships between pasture characteristics and post-weaning daily live weight gain (DLWG) were also examined. The treatments studied were native grassland (NG) and improved pasture, oversown withLotus corniculatusL. andTrifolium repensL. with annual applications of either 13 and 26 kg P/ha. From 1996 to 2001 the treatments were evaluated each year with a new group of calves. Total herbage yields of the oversown pastures were not always higher than NG in the initial years, but legume production increased, although without significant differences between P rates on legume or total yield. This was also reflected in the N and P status of the swards. In the last 2 years legume proportion had declined to <0·1, but total herbage yield was significantly higher in the improved pastures. The average DLWG over the 6 years of measurements were 0·319, 0·478 and 0·586 kg/day for NG, P1 and P2, respectively, with average total live weight gain increased 1·8- and 2·5-fold by the legume introduction and annual addition of 13 and 26 kg P/ha, respectively. The study demonstrated that the evaluation of pasture response to P application should not be limited to assessing forage yield increase. Phosphorus availability in the herbage was a better predictor of animal performance than pasture yield. The study highlights that the benefits of oversowing and fertilizer inputs are short-lived, as withholding of fertilizer in the last 2 years resulted in a loss of sown legumes and decline in animal production.
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Swan, A. D., M. B. Peoples, R. C. Hayes, G. D. Li, G. R. Casburn, J. I. McCormick, and B. S. Dear. "Farmer experience with perennial pastures in the mixed farming areas of southern New South Wales: on-farm participatory research investigating pasture establishment with cover-cropping." Crop and Pasture Science 65, no. 10 (2014): 973. http://dx.doi.org/10.1071/cp13448.
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In 2009, 95 farmers in the mixed farming zone of southern New South Wales (NSW), average annual rainfall 450–700 mm, were surveyed about their use of perennial pasture species. Survey responses indicated that, on average, 52% of land was under crop, 29% contained perennial pasture and 19% annual pastures. The proportion of land sown to perennial pastures and the species used differed with rainfall. Farmers identified concerns about the cost of establishment and poor survival of perennial pasture species as constraints to wider adoption. The survey also revealed that cover-cropping (sowing pasture species under the final grain crop in a cropping phase) was the dominant method of pasture establishment. Large-scale, on-farm participatory experiments were sown with the farm machinery, three at Ariah Park and one at Brocklesby in southern NSW in 2009 (annual rainfall 100 mm less than long-term average), and a further two experiments (one at each location) commenced in 2010 (annual rainfall >200 mm above average). These experiments compared the effect of cereal cover-crop sowing rate (standard rates used by the collaborating farmer and half of the standard rate) on the establishment of the perennials lucerne (Medicago sativa), phalaris (Phalaris aquatica), cocksfoot (Dactylis glomerata), and chicory (Cichorium intybus) sown in different mixes and rates with various annual legume species. The persistence and productivity of individual species were monitored for 2 years after sowing. Results indicated little or no effect of the presence of a cover-crop on the initial establishment of any of the perennials, but pasture species survival were severely affected by cover-crop sowing rates as low as half of the farmer practice (10 kg barley or 12 kg wheat ha–1) in 2009. Despite higher than average annual rainfall in 2010 and 2011, the residual effect of establishing pastures under a cover-crop in 2009 was poorer persistence and lower productivity by lucerne at the standard cover-cropping rate, and by phalaris, cocksfoot and chicory at all cover-crop rates, and an increased incidence of weeds. Similar responses to cover-cropping occurred between 2010 and 2012, even with the wetter establishment conditions in 2010, for phalaris, chicory and weeds, despite demonstration at Ariah Park that higher populations of individual perennial species could be achieved by doubling the sowing rate of pasture seed in 2010. Lucerne compensated for lower plant numbers by increasing herbage growth in response to rainfall, but phalaris could not and total pasture productivity over the first 2 years after establishment was greatly reduced by the use of cover-crops in both 2009 and 2010. Cover-cropping also reduced annual legume seedset, which could have implications for future pasture performance. Lucerne was the most consistently productive perennial pasture species evaluated regardless of establishment technique or climatic conditions.
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Smith, Rowan W., Mick Statham, Tony W. Norton, Richard P. Rawnsley, Helen L. Statham, Alistair J. Gracie, and Daniel J. Donaghy. "Effects of wildlife grazing on the production, ground cover and plant species composition of an established perennial pasture in the Midlands region, Tasmania." Wildlife Research 39, no. 2 (2012): 123. http://dx.doi.org/10.1071/wr11032.
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Context Management of grazing wildlife on private land in Tasmania is a contentious issue for landowners, animal-welfare groups and the Tasmanian Government. Wildlife species known to graze pasture include Tasmanian pademelon (Thylogale billardierii), Bennett’s wallaby (Macropus rufogriseus rufogriseus), forester kangaroo (Macropus giganteus), brushtail possum (Trichosurus vulpecula) and fallow deer (Dama dama). Understanding the spatio-temporal patterns of wildlife grazing is important when considering wildlife-control options to mitigate pasture loss; however, limited research has been undertaken. Aims To quantify the impact of wildlife grazing on pasture production and to assess the spatial and temporal pasture biomass loss from an established pasture; to investigate the effect of protecting pastures from wildlife grazing on species composition of an existing perennial pasture; to determine whether wildlife grazing contributes to a decline in the composition of improved pasture species over time and an increase in-ground cover of less desirable grasses and broadleaf weeds; and to examine whether protecting pastures from wildlife grazing could increase ground cover. Methods Pasture biomass loss to wildlife grazing was determined by a paired exclusion-cage method over a 26-month period from February 2008 to April 2010. A quantitative pasture model was used to simulate pasture growth at the study site. Changes in the botanical composition of the sward in response to wildlife grazing were determined by hand-separation, drying and weighing of harvested material, and also by visual estimation of the ground cover of individual plant species. A wildlife faecal-pellet survey was used to develop an index of wildlife feeding activity. Key results Pasture loss to wildlife grazing varied spatially and temporally. Pasture loss decreased with increasing distance from the edge of cover vegetation. The proportion of pasture lost increased during periods of slow pasture growth. Visual estimates of ground cover showed that grazing by wildlife resulted in an increase in bare ground in unprotected swards, whereas protection from grazing resulted in an increase in production of perennial and annual species, as determined by hand-separation of harvested material, and a decrease in bare ground as determined by visual estimate. Faecal-pellet surveys were found to be strongly correlated with pasture biomass losses. Conclusions The proportion of pasture loss to wildlife grazing was found to be influenced by distance from native vegetation and also by pasture availability, which was seasonal. Wildlife can alter the composition of pastures by reducing the ground cover and yield of improved grasses. Continual grazing of pastures by wildlife in addition to rotational sheep grazing may increase the amount of bare ground. Implications Wildlife-control methods need to be carefully chosen if the intended benefits of alleviating pasture biomass losses are to be achieved. Quantifying the loss of pasture is important because it enables the extent and significance of losses to be determined and may inform decisions about the most appropriate wildlife control measures to adopt. Controlling wildlife during periods of slow pasture growth may be important in preventing damage and yield loss of plant species actively growing during these times. Failure to control wildlife may result in a decrease in the composition of desirable plant species.
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Cayley, J. W. D., M. C. Hannah, G. A. Kearney, and S. G. Clark. "Effects of phosphorus fertiliser and rate of stocking on the seasonal pasture production of perennial ryegrass-subterranean clover pasture." Australian Journal of Agricultural Research 49, no. 2 (1998): 233. http://dx.doi.org/10.1071/a97113.
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The response of pastures based on Lolium perenne L. and Trifolium subterraneum L. to single superphosphate was assessed at Hamilton, Victoria, by measuring the growth of pastures during winter, spring, and summer over 7 years from 1979 to 1987. The seasons were defined by the pattern of pasture production, rather than by calendar months. Winter was the period of constant growth rate following the autumn rain; spring was the period of accelerating growth rate until growth rate changed abruptly following the onset of dry summer weather. Pastures were grazed with sheep at a low, medium, or high grazing pressure, corresponding generally to stocking rates of 10, 14, or 18 sheep/ha. At each level of grazing pressure, single superphosphate was applied at 5 rates from 1979 to 1982; the highest rate, expressed as elemental phosphorus (P), was reduced from 100 to 40 kg/ha during this time. In addition there was an unfertilised treatment. In 1984, fertiliser was applied at 6 rates from 4 to 40 kg P/ha. No fertiliser was applied in the remaining years, including 1983. Pasture production was measured from 1979 to 1982 and from 1985 to 1987. Total pasture dry matter (DM) accumulation per year at the highest stocking rate was less than the other treatments in 4 of the years. Averaged over all years and fertiliser treatments, the annual net production was 10·1, 10·1, and 9·0 t DM/ha (P < 0·05) for plots grazed at low, medium, and high stocking rates, respectively. The amount of fertiliser required to reach a given proportion of maximum yield response did not vary between winter and spring in any year, but the greater potential yield in spring (P < 0 ·001) meant that as more fertiliser was applied, the disparity between pasture grown in winter and pasture grown in spring increased. Differences in this disparity between extreme levels of P ranged from 1·4 t DM/ha in a drought to about 7 t DM/ha in a good season. The implications for managing farms when pastures are fertilised at higher rates than currently practised by district farmers are that systems of animal production with a requirement for plentiful good quality pasture in spring, such as ewes lambing in spring, should be used. The benefit of spring lambing over autumn lambing was supported when the 2 systems were compared over 26 years using the GrassGro decision support system. Well fertilised pasture systems will also allow more scope for conserving pasture as hay or silage, and increase opportunities for diversification in the farming enterprise, such as spring-growing crops.
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Cayley, J. W. D., M. C. Hannah, G. A. Kearney, and S. G. Clark. "Corrigendum to: Effects of phosphorus fertiliser and rate of stocking on the seasonal pasture production of perennial ryegrass-subterranean clover pasture." Australian Journal of Agricultural Research 53, no. 12 (2002): 1383. http://dx.doi.org/10.1071/ar97113_co.
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The response of pastures based on Lolium perenne L. and Trifolium subterraneum L. to single superphosphate was assessed at Hamilton, Victoria, by measuring the growth of pastures during winter, spring, and summer over 7 years from 1979 to 1987. The seasons were defined by the pattern of pasture production, rather than by calendar months. Winter was the period of constant growth rate following the autumn rain; spring was the period of accelerating growth rate until growth rate changed abruptly following the onset of dry summer weather. Pastures were grazed with sheep at a low, medium, or high grazing pressure, corresponding generally to stocking rates of 10, 14, or 18 sheep/ha. At each level of grazing pressure, single superphosphate was applied at 5 rates from 1979 to 1982; the highest rate, expressed as elemental phosphorus (P), was reduced from 100 to 40 kg/ha during this time. In addition there was an unfertilised treatment. In 1984, fertiliser was applied at 6 rates from 4 to 40 kg P/ha. No fertiliser was applied in the remaining years, including 1983. Pasture production was measured from 1979 to 1982 and from 1985 to 1987. Total pasture dry matter (DM) accumulation per year at the highest stocking rate was less than the other treatments in 4 of the years. Averaged over all years and fertiliser treatments, the annual net production was 10·1, 10·1, and 9·0 t DM/ha (P < 0·05) for plots grazed at low, medium, and high stocking rates, respectively. The amount of fertiliser required to reach a given proportion of maximum yield response did not vary between winter and spring in any year, but the greater potential yield in spring (P < 0 ·001) meant that as more fertiliser was applied, the disparity between pasture grown in winter and pasture grown in spring increased. Differences in this disparity between extreme levels of P ranged from 1·4 t DM/ha in a drought to about 7 t DM/ha in a good season. The implications for managing farms when pastures are fertilised at higher rates than currently practised by district farmers are that systems of animal production with a requirement for plentiful good quality pasture in spring, such as ewes lambing in spring, should be used. The benefit of spring lambing over autumn lambing was supported when the 2 systems were compared over 26 years using the GrassGro decision support system. Well fertilised pasture systems will also allow more scope for conserving pasture as hay or silage, and increase opportunities for diversification in the farming enterprise, such as spring-growing crops.
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Antoniel, Laísa S., Giuliani do Prado, Adriano C. Tinos, Gabriel A. Beltrame, João V. C. de Almeida, and Gustavo P. Cuco. "Pasture production under different irrigation depths." Revista Brasileira de Engenharia Agrícola e Ambiental 20, no. 6 (June 2016): 539–44. http://dx.doi.org/10.1590/1807-1929/agriambi.v20n6p539-544.
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ABSTRACT This study aimed to evaluate the production of two pasture species, Brachiaria brizantha cv. BRS Piatã and Panicum maximum cv. Mombaça, under different irrigation depths. The experiment was carried out from May to December 2014, at the State University of Maringá, in the municipality of Cidade Gaúcha-PR, Brazil. The experiment was set out in a strip-plot design, with four replicates, six irrigation depths in the plot and two pasture species in the subplot. Irrigation depths were represented by a percentage of reference evapotranspiration (ET0), which was estimated by the Penman-Monteith equation. Four pasture cuts were performed during the studied period and there were no differences between the yields of both evaluated pasture species; however, irrigation depths caused a quadratic response on pasture yield. The maximum values of dry matter yield of the pastures under irrigated conditions were 52.1, 41.6, 26.2 and 25.1% higher than under non-irrigated conditions, for the 1st, 2nd, 3rd and 4th cuts, respectively. Irrigation depths that applied water volumes close to ET0 promoted considerable increases in pasture yield.
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Chapman, D. F., A. J. Parsons, and S. Schwinning. "Management of clover in grazed pastures: expectations, limitations and opportunities." NZGA: Research and Practice Series 6 (January 1, 1996): 55–64. http://dx.doi.org/10.33584/rps.6.1995.3378.
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The value of white clover as a component of New Zealand pastures is undeniable, but it is also widely recognised that clover has limitations as a pasture plant and that these can lead to inefficiencies in the performance of grass/clover associations. This paper identifies some of the limitations to optimising the contribution of clover in complex soil/pasture/animal systems, within the context of the expectations commonly held of clover. Limitations to exploiting the greater digestive efficiency and short-term intake rate of clover compared to grass when they are grown in a mixture include animal behaviour responses that sometimes impose a restriction on total daily intake of nutrients, and the fact that clover often constitutes less than 20% of the pasture. Nitrogen inputs and yield advantages are also restricted by the low clover content of pastures. A simulation model is used to analyse the co-existence of grass and clover as influenced by N dynamics. This model explains the basis for selfregulation by grass/clover mixtures of the amount of mineral N in the soil. Self-regulation minimises N losses from mixtures, but the dynamic response of grass and clover to N availability also means that there may only be limited scope for increasing the overall clover content, or decreasing the spatial heterogeneity in clover distribution, of a mixture. Managing grass/clover associations to realise the benefits of white clover therefore means manipulating a complex system, where the outcomes of manipulation depend as much on the response of the companion grass as on the response of the clover itself. Opportunities for attaining a higher clover content in pastures include: manipulating the preferences of animals for clover versus grass; spatially separating grass and clover within fields; increasing the metabolic efficiency of N fixation in clover; uncoupling the apparent link between rhizobium symbiosis and the N content of clover leaves; and modifying the stolon morphology of clover as a way of increasing clover presence in favourable microsites within the pasture. Keywords: genetic improvement, grass/clover competition, grazing behaviour, intake, models, N fixation, nitrogen dynamics, nutritive value
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Armstrong, RD, KR Helyar, and EK Christie. "Vesicular-arbuscular mycorrhiza in semi-arid pastures of south-west Queensland and their effect on growth responses to phosphorus fertilizers by grasses." Australian Journal of Agricultural Research 43, no. 5 (1992): 1143. http://dx.doi.org/10.1071/ar9921143.
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Field and controlled environment studies were undertaken to determine the seasonal variation in vesicular-arbuscular mycorrhizal (VAM) propagules under different types of vegetation in the mulga (Acacia aneura) shrublands of south-western Queensland and how inoculation with VAM affects the growth and response to phosphorus fertilizers of several grasses common to this region. A most probable number (MPN) technique was used to estimate the number of viable VAM propagules under mulga shrubland and native pasture. There was a pronounced rise in MPN at a native pasture site from June to November, peaking at 1 propagule/g soil, before declining between November and May to non detectable concentrations. In the mulga shrubland site, MPN remained very low (less than 0.2 propagules/g soil) throughout the study. Pasture species in the field were screened for VAM infection in both winter and summer. Only three of the 14 species sampled were infected with VAM in winter (June) after a long drought. In contrast, 10 of the 14 species sampled in December possessed VAM-infected roots. A pot experiment was conducted to examine the influence of VAM inoculation on growth and the response to phosphate fertilizer of several important pasture grasses in pastures derived from mulga shrublands. The treatments comprised a factorial combination of inoculation or non-inoculation with VAM, four grass species (Aristida armata, Cenchms ciliaris cv. USA, Digitaria ammophilla, and Thyridolepis mitchelliana), and four rates of P fertilizer designed to range over very deficient to non-limiting for each species. All species except D. ammophilla produced growth responses to VAM inoculation. Though C. ciliaris and T. mitchelliana responded to VAM inoculation only in soil unamended with P fertilizer, A. amata showed growth responses across all P rates examined, suggesting some factor other than P was limiting this species. The growth response of the grasses to VAM inoculation was poorly correlated with the percentage of root infected with VAM. D. ammophilla had the highest levels of root infection (32%) despite producing no growth response to VAM. In contrast, T. mitchelliana had less than 2% of the root infected with VAM. All species had thin fibrous roots with long (0.35-0.47 mm), frequent root hairs. The differential growth responses to VAM inoculation of A. armata compared with the other grasses may provide a management strategy to control Aristida ingress into pastures established from mulga shrublands.
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Bolland, M. D. A., and I. F. Guthridge. "Responses of intensively grazed dairy pastures to applications of fertiliser nitrogen in south-western Australia." Australian Journal of Experimental Agriculture 47, no. 8 (2007): 927. http://dx.doi.org/10.1071/ea06014.
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For the first time, we quantified pasture dry matter (DM) responses to applied fertiliser nitrogen (N) for intensively grazed, rain-fed, dairy pastures on sandy soils common in the Mediterranean-type climate of south-western Australia. The pastures are composed of subterranean clover (Trifolium subterraneum L.) and annual and Italian ryegrass (Lolium rigidum Gaud. and L. multiflorum Lam.). Six rates of N, as urea (46% N), were applied to 15 m by 15 m plots four times during 2002 and after each of the first 5–7 grazings in 2003 and 2004, throughout the typical April–October growing season. Total rates of N applied in the first year of the experiments were 0, 60, 120, 160, 200 and 320 kg N/ha, which were adjusted in subsequent years as detailed in the ‘Materials and methods’ section of this paper. The pastures in the experiments were rotationally grazed, by starting grazing when ryegrass plants had 2–3 leaves per tiller. The amount of pasture DM on each plot was measured before and after each grazing and was then used to estimate the amount of pasture DM consumed by the cows at each grazing for different times during the growing season. Linear increases (responses) of pasture DM to applied N occurred throughout the whole growing season when a total of up to 320 kg N/ha was applied in each year. No maximum yield plateaus were defined. Across all three experiments and years, on average in each year, a total of ~5 t/ha consumed DM was produced when no N was applied and ~7.5 t/ha was produced when a total of 200 kg N/ha was applied, giving ~2.5 t/ha increase in DM consumed and an N response efficiency of ~12.5 kg DM N/kg applied. As more fertiliser N was applied, the proportion of ryegrass in the pasture consistently increased, whereas clover content decreased. Concentrations of nitrate-N in the DM consistently increased as more N was applied, whereas concentrations of total N, and, therefore, concentration of crude protein in the DM, either increased or were unaffected by applied N. Application of N had no effect on concentrations of other mineral elements in DM and on dry matter digestibility and metabolisable energy of the DM. The results were generally consistent with findings of previous pasture N studies for perennial and annual temperate and subtropical pastures. We have shown that when pasture use for milk production has been maximised in the region, it is profitable to apply fertiliser N to grow extra DM consumed by dairy cows; conversely, it is a waste of money to apply N to undergrazed pastures to produce more unused DM.
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Clark, S. G., E. A. Austen, T. Prance, and P. D. Ball. "Climate variability effects on simulated pasture and animal production in the perennial pasture zone of south-eastern Australia.1. Between year variability in pasture and animal production." Australian Journal of Experimental Agriculture 43, no. 10 (2003): 1211. http://dx.doi.org/10.1071/ea02101.
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Climate variability is a major constraint to farming in south-eastern Australia and one that is out of the farmers' control. However, a better understanding of long-term climate variability would be beneficial for on-farm management decisions. A series of long-term simulations were undertaken with the GrassGro decision support tool to determine the effect of climate variability on pasture and animal production at 6 locations in south-eastern Australia. The simulations ran from 89 to 119 years using daily weather records from each location. All simulations were for spring-lambing flocks of medium sized Merino ewes stocked at above-average district stocking rates, grazing well-fertilised, perennial grass–subterranean clover pastures. Annual rainfall total and, in particular, the distribution of rainfall during the year, were found to be more important than other weather variables in determining the amount of pasture grown in a year. The timing of the season opening rains (autumn break) was most important. The localities varied in their responses to climate variability, particularly in the timing of the autumn break; the pasture growth response to winter rainfall; and the relationship between rainfall and animal production.
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Zanine, A. M., G. P. R. Motta, D. J. Ferreira, A. L. de Souza, M. D. Ribeiro, L. J. V. Geron, M. Fajardo, M. Sprunk, and R. M. A. Pinho. "Milk performance and grazing behaviour of dairy cows in response to pasture allowance." Animal Production Science 59, no. 4 (2019): 749. http://dx.doi.org/10.1071/an17513.
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This study aimed to evaluate the effects of pasture allowances on forage production, milk yield and composition, and grazing behaviour of Holstein cows during autumn. Thirty-six Holstein cows calving in the autumn were allocated to blocks considering: calving date, bodyweight, and body score. Treatments consisted of three pasture allowances as follows: high (HA; 38.4 kg DM/cow.day), medium (MA; 30.3 kg DM/cow.day), and low (LA; 26.8 kg DM/cow.day) pasture allowances. Forage mass and forage height pre-grazing were similar (P > 0.05) for all grazing targets. Pasture-use efficiency was affected (P < 0.05) by the pasture allowance. The highest and lowest efficiency was obtained with treatments LA and HA, respectively. The neutral detergent fibre content of forage harvesting was affected (P < 0.05) by the pasture allowance, with average of 44.8, 47.0, and 49.4 to HA, MA, and LA, respectively. There was an effect of pasture allowances (P < 0.05) on the milk yield per hectare and milk yield per cow. The highest production was observed in LA (438 L/ha.day) and the lowest in HA (314 L/ha.day). The percentage of milk fat, milk protein, and milk fat (g/cow.day) did not differ (P > 0.05) among pasture allowances. There was effect (P < 0.05) of pasture allowance with higher grazing time (369 min) and lower rumination time (23.3 min) observed to HA. Pasture allowances affected (P < 0.05) the total number of bites/day and bites/min, but did not affect (P > 0.05) bite mass. The pasture managements with low (26.8 kg DM/cow.day) pasture allowances provided better conditions for milk yield per area, likely due to the better grazing efficiency. However, pasture allowance provide little measurable changes on grazing behaviour.
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Jakobsson, Simon, Heather Wood, Johan Ekroos, and Regina Lindborg. "Contrasting multi-taxa functional diversity patterns along vegetation structure gradients of woody pastures." Biodiversity and Conservation 29, no. 13 (August 18, 2020): 3551–72. http://dx.doi.org/10.1007/s10531-020-02037-y.
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Abstract Woody pastures represent keystone habitats for biodiversity in agricultural landscapes, contributing to increased resource availability, landscape heterogeneity and structural variability. High taxonomic diversity is closely linked to vegetation structure in woody pastures, but examining functional characteristics of species assemblages can shed more light on the ecological mechanisms driving divergent responses to habitat characteristics and help guide good management practices. To this end, we use a multi-taxa approach to investigate how plant, bat and bird taxonomic and functional diversity are affected by pasture tree and shrub density, structural complexity and proximate forest cover in southern Sweden. In particular, we use a trait exclusion approach to estimate the sensitivity of diversity-environment relationships to specific traits. We found little congruence between corresponding diversity metrics across taxa. Bird species richness responded stronger to environmental variables than functional diversity metrics, whereas the functional response to the environment was stronger than the taxonomic response among plants and bats. While increasing tree densities increased the taxonomic diversity of all three taxa, a simultaneous functional response was only evident for plants. Contrasting measures of vegetation structure affected different aspects of functional diversity across taxa, driven by different traits. For plants and birds, traits linked to resource use contributed particularly to the functional response, whereas body mass had stronger influence on bat functional diversity metrics. Multi-taxa functional approaches are essential to understand the effects of woody pasture structural attributes on biodiversity, and ultimately inform management guidelines to preserve the biological values in woody pastures.
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Tubiello, F. N., J. F. Soussana, and S. M. Howden. "Crop and pasture response to climate change." Proceedings of the National Academy of Sciences 104, no. 50 (December 6, 2007): 19686–90. http://dx.doi.org/10.1073/pnas.0701728104.
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Feldhake, Charles M., David M. Glenn, and Donald L. Peterson. "Pasture Soil Surface Temperature Response to Drought." Agronomy Journal 88, no. 4 (July 1996): 652–56. http://dx.doi.org/10.2134/agronj1996.00021962008800040025x.
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Aarssen, L. W., and Roy Turkington. "Responses to defoliation in Holcus lanatus, Lolium perenne, and Trifolium repens from three different-aged pastures." Canadian Journal of Botany 65, no. 7 (July 1, 1987): 1364–70. http://dx.doi.org/10.1139/b87-188.
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The effects of defoliation on biomass distribution were studied in plants of Holcus lanatus L., Lolium perenne L., and Trifolium repens L. collected from three different-aged pastures. Individual plants were cloned and ramets from each clone were subjected to clipped and unclipped treatments over a period of 1 year. In the unclipped treatment for each species, plants from the three pastures showed no differences in the extent of clonal growth (i.e., tiller or stolon production). In the clipped treatment, however, plants from the oldest pasture displayed significantly more extensive clonal growth than plants from the younger pastures. With increasing pasture age, there was a significant trend of increasing compensatory clonal growth in response to defoliation for all three species. This may be interpreted as a consequence of selection pressure from grazing. However, the data do not suggest that the grass–grazer relationship is a mutualism. Alternative interpretations are considered.
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Moore, A. D., P. J. Vickery, M. J. Hill, J. R. Donnelly, and G. E. Donald. "Combining satellite data with a simulation model to describe spatial variability in pasture growth at a farm scale." Australian Journal of Experimental Agriculture 39, no. 3 (1999): 285. http://dx.doi.org/10.1071/ea98109.
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Practical application of simulation modelling as a decision aid for grazing system management usually involves an assumption of uniformity of model inputs over a farm paddock or property. In reality, paddocks and farms display high spatial variability in model inputs. There is considerable interest in assessing the significance of this spatial variablity for anmal production and enterprise profitability. This study seeks to demonstrate the use of spatial data with the GRAZPLAN pasture model to provide estimates of annual net primary production from pastures at a farm scale on the Northern Tablelands of New South Wales, Australia. The GRAZPLAN pasture model was validated against data from 2 separate field experiments for a typical improved pasture based on Phalaris aquatica from 1968 to 1972. A spatial coverage, classifying paddocks into 9 pasture types based on a botanical survey, was used to define the pasture parameter sets used in simulations. A Landsat TM satellite image classified to give 3 pasture growth status classes was used to define within-paddock levels of a fertility index used in the simulation model. Simulations over 1975–94 were conducted for all combinations of pasture types and fertility scalar values using climate data for the CSIRO Pastoral Research Laboratory near Armidale. Simulation output was written to a lookup table and imported into a PC-based geographic information system. The spatial data layers were combined to form a display template representing spatial variation in pasture type, pasture condition and fertility. The spatial template was reclassified using the lookup tables to create maps of annual net primary production from pastures. Spatial variability in simulated annual net primary production was greater for the paddocks with diverse mixtures of sown and native species than for the more uniform highly improved or pure native pastures. The difference in response to rainfall of simulated net primary production was greater between different pastures types than between different levels of the fertility index. The resulting maps provide a demonstration of the way in which satellite imagery and other data can be interfaced with a decision support system to provide information for use in precision management of grazing systems. Implementation of such methods as a management tool will depend on development of quantitative spatial data layers which provide accurate and repeatable initial conditions and parameter values for simulation models.
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Štýbnarová, Marie, Josef Hakl, Pavlína Mičová, Hana Karabcová, Oldřich Látal, Karel Fiala, and Jan Pozdíšek. "Species Diversity and Botanical Composition of Permanent Grassland as a Response to Different Grazing Management Practices." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 63, no. 4 (2015): 1201–9. http://dx.doi.org/10.11118/actaun201563041201.
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The effects of different levels of grazing utilization (two, three and four grazing cycles per year) and mineral fertilization (nil-fertilization; N100P30K60) on the botanical composition of permanent grasslands were studied in the locality of Rapotín (Czech Republic, 332 m a.s.l.) from 2003–2010. The vegetation of the experimental pasture was classified as Cynosurion. It was found that moderate treatment (three grazing cycles per year) without mineral fertilization showed the highest value of diversity index (DI = 6.08), and maximum dominance of legumes (Dmax = 9.1%), particularly Trifolium repens. The highest dominance of grasses (Dmax = 77.7%), mainly Dactylis glomerata and Elytrigia repens, was achieved with the fertilized treatment utilized in two grazing cycles per year. Based on RDA results, tested management treatments explained 26% of species composition variability, where effect of number of grazing cycles per year was five-times higher than effect of fertilization. We recommend grassland utilization in three grazing cycles per year as the most suitable way from the objective of both species diversity and botanical composition of pastures in similar site conditions. Pasture fertilization should be more controlled by careful consideration of individual pasture goals, actual nutrient status of the soil and possible environmental risks.
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Gourley, CJP. "Predicting the responsiveness of pasture to potassium fertiliser in Victoria." Australian Journal of Experimental Agriculture 29, no. 3 (1989): 377. http://dx.doi.org/10.1071/ea9890377.
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A quantitative model has been developed from the results of 180 field experiments in Victoria, to estimate pasture responses to rates of potassium fertiliser, where the amount of soil potassium extracted by 0.05 mol/L HCl, soil texture and annual rainfall are known. Available soil potassium accounted for 42% of the variation in pasture responses. Soil texture did not affect the magnitude of the response to applied potassium, but there was an apparent affect of soil texture on the curvature of the response curve. Potassium fertiliser recommendations in Victoria can now be based on the results of 180 field experiments which measured the response of pasture to potassium fertiliser at different locations and years, under a range of management conditions.
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Behrendt, Karl, Oscar Cacho, James M. Scott, and Randall Jones. "Optimising pasture and grazing management decisions on the Cicerone Project farmlets over variable time horizons." Animal Production Science 53, no. 8 (2013): 796. http://dx.doi.org/10.1071/an11174.
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This study addresses the problem of balancing the trade-offs between the need for animal production, profit, and the goal of achieving persistence of desirable species within grazing systems. The bioeconomic framework applied in this study takes into account the impact of climate risk and the management of pastures and grazing rules on the botanical composition of the pasture resource, a factor that impacts on livestock production and economic returns over time. The framework establishes the links between inputs, the state of the pasture resource and outputs, to identify optimal pasture development strategies. The analysis is based on the application of a dynamic pasture resource development simulation model within a seasonal stochastic dynamic programming framework. This enables the derivation of optimum decisions within complex grazing enterprises, over both short-term tactical (such as grazing rest) and long-term strategic (such as pasture renovation) time frames and under climatic uncertainty. The simulation model is parameterised using data and systems from the Cicerone Project farmlet experiment. Results indicate that the strategic decision of pasture renovation should only be considered when pastures are in a severely degraded state, whereas the tactical use of grazing rest or low stocking rates should be considered as the most profitable means of maintaining adequate proportions of desirable species within a pasture sward. The optimal stocking rates identified reflected a pattern which may best be described as a seasonal saving and consumption cycle. The optimal tactical and strategic decisions at different pasture states, based on biomass and species composition, varies both between seasons and in response to the imposed soil fertility regime. Implications of these findings at the whole-farm level are discussed in the context of the Cicerone Project farmlets.
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Whelan, BR. "Uptake of selenite fertilizer by subterranean clover pasture in Western Australia." Australian Journal of Experimental Agriculture 29, no. 4 (1989): 517. http://dx.doi.org/10.1071/ea9890517.
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. Subterranean clover (Trifolium subterraneum) based pastures were fertilised with sodium selenite at 9 rates from 0 to 800 g Se/ha on 2 sites in 1983. In order to measure the residual value in 1984 and 1985, further applications of sodium selenite were superimposed on the original 9 treatments. Green pasture was sampled annually, dry pasture was sampled once, only in 1984 and the concentration of selenium in the pasture was measured. The sampled pasture was sorted into 2 components: subterranean clover, and non-subterranean clover. Except for the third site that had a quadratic response for the non-subterranean clover component of the pasture, the concentration of selenium in plants increased linearly with application rate. The selenium concentration in subterranean clover was lower than that in the other species in the pasture. Differences between years were large: in 1985, the concentration in plant material was twice that in 1983 and 1984. The dry summer feed had higher concentrations of selenium than the green pasture. The residual value of selenite was 25% in the first year and 15% in the second year. Adequate dietary levels of selenium for sheep would require an annual application of about 200 g sodium selenite/ha to these soils.
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Quirk, M. F., J. J. Bushell, R. J. Jones, R. G. Megarrity, and K. L. Butler. "Live-weight gains on leucaena and native grass pastures after dosing cattle with rumen bacteria capable of degrading DHP, a ruminal metabolite from leucaena." Journal of Agricultural Science 111, no. 1 (August 1988): 165–70. http://dx.doi.org/10.1017/s0021859600082976.
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SummaryThe effect on live-weight gain from dosing cattle with rumen bacteria capable of degrading 3-hydroxy-4(l H)-pyridone (DHP) was measured on cattle grazing leucaena and native grass pastures in south-east Queensland. Dosing increased the growth rate of cattle grazing only leucaena pasture: from 0·52 kg/head per day when not dosed, to 1·03 kg/head per day when dosed, in the period 6·19 weeks after treatment. Dosing did not affect the growth rate of cattle either grazing leucaena with native pasture, or grazing only native pasture. The introduced bacteria spread naturally to untreated cattle after 19 weeks post-dosing.The response to dosing occurred when untreated cattle grazing only leucaena pasture had high urinary concentrations of DHP (maximum 0·28%) and low concentrations of serum thyroxine (< 30 nmol/1). The results show that DHP-induced depressions in growth rate may occur in this environment when cattle graze mainly on leucaena-based pasture. Dosing with DHP-degrading bacteria will overcome this problem.
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Peoples, M. B., and J. A. Baldock. "Nitrogen dynamics of pastures: nitrogen fixation inputs, the impact of legumes on soil nitrogen fertility, and the contributions of fixed nitrogen to Australian farming systems." Australian Journal of Experimental Agriculture 41, no. 3 (2001): 327. http://dx.doi.org/10.1071/ea99139.
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Experimental estimates of amounts of foliage nitrogen (N) fixed in Australian pastures range from 2 to 284 kg N/ha.year for annual and perennial legumes growing in temperate and tropical environments. Differences in the amounts of N2 fixed relate primarily to the legume content and net productivity of pastures. On average, close to 20–25 kg of shoot N are fixed for every tonne of legume herbage dry matter produced across a wide range of environments. Strategies likely to improve the potential for N2 fixation include: (i) rhizobial inoculation at time of first sowing a new legume species; (ii) amelioration of nutritional problems (applications of superphosphate or lime); (iii) manipulation of pasture composition (herbicide applications to remove grasses in annual pastures in the year prior to cropping); and (iv) including lucerne to offset the year-to-year variability in N2 fixation inputs from annual legumes. However, pasture response to such management treatments and the subsequent availability of soil mineral N may be modified by livestock effects on nutrient cycling, pasture productivity and botanical composition. Conclusions about the relative size of the contributions of fixed N to the N economies of Australian farming systems depend on whether or not estimates of fixed N are included for nodulated roots. Thus residual net inputs of fixed N after each year of a legume-based pasture are generally rated sufficient to balance the N removed by at least 1 subsequent wheat crop provided estimates of below-ground N are included in calculations. Pasture type influences the duration of subsequent rotational benefits and while residual effects on mineral N are commonly exhausted within 2 years after an annual legume-based pasture phase, N carry-over following lucerne generally lasts considerably longer.
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Strong, W. M., R. C. Dalal, E. J. Weston, K. J. Lehane, J. E. Cooper, A. J. King, and C. J. Holmes. "Sustaining productivity of a Vertosol at Warra, Queensland, with fertilisers, no-tillage or legumes. 9. Production and nitrogen benefits from mixed grass and legume pastures in rotation with wheat." Australian Journal of Experimental Agriculture 46, no. 3 (2006): 375. http://dx.doi.org/10.1071/ea05007.
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Reduced supplies of nitrogen (N) in many soils of southern Queensland that were cropped exhaustively with cereals over many decades have been the focus of much research to avoid declines in profitability and sustainability of farming systems. A 45-month period of mixed grass (purple pigeon grass, Setaria incrassata Stapf; Rhodes grass, Chloris gayana Kunth.) and legume (lucerne, Medicago sativa L.; annual medics, M. scutellata L. Mill. and M. truncatula Gaertn.) pasture was one of several options that were compared at a fertility-depleted Vertosol at Warra, southern Queensland, to improve grain yields or increase grain protein concentration of subsequent wheat crops. Objectives of the study were to measure the productivity of a mixed grass and legume pasture grown over 45 months (cut and removed over 36 months) and its effects on yield and protein concentrations of the following wheat crops. Pasture production (DM t/ha) and aboveground plant N yield (kg/ha) for grass, legume (including a small amount of weeds) and total components of pasture responded linearly to total rainfall over the duration of each of 3 pastures sown in 1986, 1987 and 1988. Averaged over the 3 pastures, each 100 mm of rainfall resulted in 0.52 t/ha of grass, 0.44 t/ha of legume and 0.97 t/ha of total pasture DM, there being little variation between the 3 pastures. Aboveground plant N yield of the 3 pastures ranged from 17.2 to 20.5 kg/ha per 100 mm rainfall. Aboveground legume N in response to total rainfall was similar (10.6–13.2 kg/ha per 100 mm rainfall) across the 3 pastures in spite of very different populations of legumes and grasses at establishment. Aboveground grass N yield was 5.2–7.0 kg/ha per 100 mm rainfall. In most wheat crops following pasture, wheat yields were similar to that of unfertilised wheat except in 1990 and 1994, when grain yields were significantly higher but similar to that for continuous wheat fertilised with 75 kg N/ha. In contrast, grain protein concentrations of most wheat crops following pasture responded positively, being substantially higher than unfertilised wheat but similar to that of wheat fertilised with 75 kg N/ha. Grain protein averaged over all years of assay was increased by 25–40% compared with that of unfertilised wheat. Stored water supplies after pasture were <134 mm (<55% of plant available water capacity); for most assay crops water storages were 67–110 mm, an equivalent wet soil depth of only 0.3–0.45 m. Thus, the crop assays of pasture benefits were limited by low water supply to wheat crops. Moreover, the severity of common root rot in wheat crop was not reduced by pasture–wheat rotation.
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DAVISON, T. M., W. N. ORR, B. A. SILVER, R. G. WALKER, and F. DUNCALFE. "Phosphorus fertilizer for nitrogen fertilized dairy pastures. 1. Long term effects on pasture, diet and soil." Journal of Agricultural Science 129, no. 2 (September 1997): 205–17. http://dx.doi.org/10.1017/s0021859697004632.
Full textAbstract:
The phosphorus fertilizer requirements and long term productivity of nitrogen-fertilized Gatton panic (Panicum maximum cv. Gatton) pastures, grazed by lactating dairy cows, were evaluated over 7 years. Cows grazed at 2·6 cows/ha on pastures that received annually 100 or 300 kg N/ha at each of 0, 22·5 or 45 kg P/ha. Phosphorus treatments were applied as single superphosphate, balanced for calcium by applications of gypsum.The soil had an initial available soil phosphorus content of 40 mg/kg (bicarbonate extraction). At zero P fertilizer (0P), extractable soil P declined at the rate of 1·9 mg/kg each year; at 22·5P it was maintained close to the original level while at 45P it increased at 6·6 mg/kg each year. Increased P fertilizer caused significant (P<0·01) increases in plant P concentration from year 2 onwards. In years 6 and 7 there was significantly less green pasture and leaf on offer in 300N pastures at 0P than with 22·5P and 45P. There was no influence of rate of P fertilizer at 100N on pasture quantity on offer in any year. There were clear trends at 100N of decreasing total pasture and green dry matter (DM) on offer over the 7 years, but not at 300N.Cows at 300N consumed more leaf in the diet in autumn and winter than at 100N. Leaf was 55–60% of the diet in summer and autumn, but decreased to 21% (100N) and 37% (300N) in winter. Dead material in the diet was always higher at 100N. Pasture leaf percentage and leaf yield were the best individual predictors of leaf percentage in the diet. Diet P selected from pasture was reduced by the higher rate of N fertilizer in each season. Estimated P concentrations of the diet selected from pasture for summer, autumn and winter averaged 0·30, 0·38 and 0·28% DM for 100N and 0·19, 0·24 and 0·18% DM for 300N treatments, respectively.The response to P fertilizer was dependent on the rate of N fertilizer applied. The critical bicarbonate extractable soil P level for this soil type, below which pasture responses occurred, was 30 mg/kg at 300N. The critical level at 100N was not reached, but was <23 mg/kg P.