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1
Mehanni, AH. "The influence of depth and salinity of watertables on the salt levels in the duplex red-brown earths of the Goulburn Valley of Victoria." Australian Journal of Experimental Agriculture 28, no. 5 (1988): 593. http://dx.doi.org/10.1071/ea9880593.
Повний текст джерелаАнотація:
The results from a survey of 269 test wells in an area with shallow watertables were used to derive a relationship between soil salinity to 60 cm depth (Y) and watertable depth (X1) and watertable salinity (X2). The survey area (730 km2) was in the Goulburn Valley of Victoria and included irrigated and non-irrigated pastures. The relationship was described by the multiple Regression ln Y = a + b ln X1 + c ln X2 The equations were: Perennial pastures ln Y = 7.3859 - 0.607l.ln X1 + 0.2925.ln X2 (r = 0.50, P= 0.0000002, n = 109) Annual pastures ln Y = 7.2690 - 0.7252.ln X1 + 0.3743.ln X2 (r=0.54, P=0.00349, n=36) Dryland pastures ln Y = 10.8417 - 1.3779.ln X1 + 0.4024.ln X2 (r= 0.73, P= 0.0003, n = 24) It was concluded that both depth and salinity of the watertable determine its hazard to soil salinity; watertable depth alone can be misleading. The effect of watertable salinity was greater than that of watertable depth. Similar models could be developed for other regions if data for the regions were available.
2
Rogers, M. E. "Irrigating perennial pasture with saline water: effects on soil chemistry, pasture production and composition." Australian Journal of Experimental Agriculture 42, no. 3 (2002): 265. http://dx.doi.org/10.1071/ea00128.
Повний текст джерелаАнотація:
In response to a local survey that revealed that many farmers in the Goulburn Valley region of Victoria did not adhere to recommendations for safely applying saline irrigation water to perennial pasture, an experiment was conducted at Tatura. Six irrigation water quality treatments, which differed in the timing of the application of saline water, were applied to perennial pasture plots over 4 irrigation seasons. Measurements made included soil EC1:5, soil SAR1:5, soil ESP, pasture dry matter production and composition, dry matter digestibility, tissue ion concentrations and mineral ash content. After 4 seasons, in which the winter rainfall for each season was significantly lower than the long-term average, soil sodicity and salinity levels appeared to reach steady values. Plots irrigated with non-saline water (0.1 dS/m, treatment 1) performed the best in terms of lower soil salinity and sodicity levels and higher dry matter production and pasture quality levels. However, for most of these measurements and for most seasons, there were no significant differences between the control plots and those irrigated with water at 1.2 dS/m (treatment 2). Soil EC1:5 and SAR1:5 levels were highest, and dry matter production and dry matter digestibility levels the lowest (particularly for the clover component), in plots irrigated with water at 2.4 dS/m throughout the season (treatment 6). There were no significant differences in soil characteristics or biomass production between the remaining 3 treatments (treatments 3, 4 and 5) or between treatment 2. These treatments had the same amount of salt applied throughout the season but differed in the pattern of salt application — whether it occurred at the beginning or end of the season, or was alternated with fresh water throughout the season. This study confirmed that in the long term, there is a reduction in the yield of perennial pastures when saline irrigation water at levels greater than 0.8–1.2 dS/m is used on the red-brown earths of the Shepparton Irrigation Region. However, the soil and pasture were more sensitive to the total amount of salt applied rather than to the pattern of salt application throughout the season. It was concluded that farmers should monitor the salinity levels of their irrigation water to avoid a build up of Na+ and Cl– in the soil profile and consequent long-term reductions in herbage production and quality.
3
Beverly, C., M. Bari, B. Christy, M. Hocking, and K. Smettem. "Predicted salinity impacts from land use change: comparison between rapid assessment approaches and a detailed modelling framework." Australian Journal of Experimental Agriculture 45, no. 11 (2005): 1453. http://dx.doi.org/10.1071/ea04192.
Повний текст джерелаАнотація:
This paper illustrates the hydrological limitations and underlying assumptions of 4 catchment modelling approaches representing different generic classes of predictive models. These models are commonly used to estimate the impacts of land use and management change on stream flow and salinity regimes within a target region. Three approaches are based on a simple conceptual framework that assumes a single layer groundwater aquifer and requires minimal information and calibration (Zhang-BC2C, CAT1D-BC2C and LUCICAT), whereas the fourth approach (CAT3D) adopts a fully distributed highly parameterised catchment model capable of simulating complex multi-layered groundwater aquifer systems. All models were applied to the Gardiner subcatchment within the Goulburn–Broken region of Victoria, identified as a National Action Plan for Salinity priority subcatchment. Current condition simulation results were compared with observed stream flow and groundwater hydrograph data. Results show that the simple frameworks predicted whole-of-catchment mean annual salt and water yield with minimum parameterisation. The fully distributed framework produced similar catchment-scale responses to the simple approaches, but required more intensive input data and solution times. However, the fully distributed framework provides finer temporal and spatial scale information within the catchment. The more detailed models (such as CAT3D) also have the predictive capacity to assess the within-catchment dynamics at a range of scales and account for landscape position and complex surface/groundwater interactions. This paper concludes that the simple frameworks are useful for judging the whole-of-catchment impacts of broad-scale land use change on catchment water yields and salinity and therefore provide valuable tools for community engagement. However, the within-catchment dynamics are not well represented and particular care must be taken when applying such models in those catchments where the interaction between groundwater and surface features result in saturated areas that are disconnected from streams. Adoption of a distributed groundwater modelling environment similar to that of CAT3D provides higher spatial resolution relative to the lumped broad scale groundwater glow system (GFS) based parameterisation adopted by the BC2C rapid assessment approaches. The developers of the BC2C model acknowledge that such models are currently limited to upland local and intermediate groundwater flow systems. Given that the majority of land salinisation is located in regions dominated by intermediate and regional groundwater systems, this tool is not well suited to adequately model regional processes. In contrast, the CAT3D distributed groundwater models are likely to be applicable across a range of scales and provide the capacity to assess the trade offs between salinity recharge and discharge intervention strategies. We conclude that more complex models (e.g. CAT3D) are needed to identify at the land management scale (paddock/farm) cost effective land use and land management changes within the catchment to improve catchment health.
4
Norman, CP. "Effect of groundwater pump management on reclaiming salinised land in the Goulburn Valley, Victoria." Australian Journal of Experimental Agriculture 35, no. 2 (1995): 215. http://dx.doi.org/10.1071/ea9950215.
Повний текст джерелаАнотація:
In 1985, groundwater pumping from shallow aquifers, with off-farm disposal, began near Girgarre in the Goulburn Valley, Victoria, to provide salinity control to about 1000 ha of farming land. Two groundwater pumps (TI02 and T103) ran continuously for the first 5 years of the project before reverting to intermittent pumping. The operation of a third pump (T103) was based on the capacity for disposal into an evaporation basin. Following 3 years of groundwater pumping, significant reductions in root-zone (0-0.6 m) soil salinity levels were recorded in both annual and perennial pasture paddocks within 350 m of a pump. Yields of perennial pasture on all monitored paddocks showed a significant increase after commencement of the project. In a paddock 300 m from a groundwater pump, average dry matter production increased from 6.3 to 17.2 t/ha. year within 4 years of pumping. Reclamation was reduced by more than a year on paddocks not subjected to irrigation, or those located >800 m from a groundwater pump. Once reclamation was achieved from continuous pumping, the introduction of intermittent pumping continued to maintain optimum soil salinity and pasture production levels on the irrigated paddocks. However, on a dryland paddock and those located >800 m from a pump, increasing fluctuations in soil salinity and soil sodicity levels were measured under this management regime.
5
Heuperman, AF, AP Repsys, and AH Mehanni. "Salinity control by pumping and re-using groundwater: its effect on watertable levels, soil salinity and farm productivity on a dairy property in the Goulburn Valley, Victoria." Australian Journal of Experimental Agriculture 26, no. 6 (1986): 669. http://dx.doi.org/10.1071/ea9860669.
Повний текст джерелаАнотація:
The introduction of watertable control by groundwater pumping on a salt-affected dairy farm in the Goulburn Valley resulted in large increases in butter fat production. Since intensive pumping started, in 1981, watertable levels showed an overall downward trend but were still subject to major fluctuations caused by irrigation and rainfall. During this period butterfat production increased from about 300 to 390 kg/ha (of productive land) and yearly pasture production rose from about 560 to 650 t/ha DM. These productivity increases are attributed to both a reduction in average soil salinity in the top 60 cm of the profile from 2400 to 1200 mg total dissolved salts per kg dry soil and an increase in irrigation water use from less than 10 M litre/ha before to nearly 12 M litre/ha after pumping started.
6
Brownlie, TS, I. Holmes, H. Delahunty, S. Salmon, and JC Hunnam. "Perceptions of anthrax in livestock from Victorian dairy farmers in the Goulburn‐Murray region of Victoria, Australia." Australian Veterinary Journal 97, no. 9 (July 22, 2019): 333–35. http://dx.doi.org/10.1111/avj.12844.
Повний текст джерела
7
Surapaneni, A., and K. A. Olsson. "Sodification under conjunctive water use in the Shepparton Irrigation Region of northern Victoria: a review." Australian Journal of Experimental Agriculture 42, no. 3 (2002): 249. http://dx.doi.org/10.1071/ea00179.
Повний текст джерелаАнотація:
The Shepparton Irrigation Region Land and Water Salinity Management Plan promotes groundwater pumping and re-use for irrigation where groundwater quality and availability allow dilution with channel water (‘conjunctive water use’) to levels that produce minimal production losses from annual and perennial pastures used widely for dairying. In addition, municipal and industrial waste waters are used on a smaller scale for irrigating pastures (and crops). An upper level of irrigation water salinity (expressed as an electrical conductivity of 0.8 dS/m) is currently recommended in the plan. This recommendation is based on empirical data from experiments on unstocked, perennial pasture collected over 2 decades on red-brown earths in the region. While the strategy has, so far, achieved acceptable control of soil salinity levels, while generally maintaining pasture yields, a concern that ‘conjunctive water use’ may not be sustainable in the long term arises from the sodicity of the groundwater and waste waters. The continual addition of sodium to clay soils, initially low in both sodium and electrolytes (upper 0.5 m depth), risks the soils becoming sodified, with attendant soil physical problems should salts be leached to below threshold electrolyte concentrations, as in winter for example. We show that clay soils supporting pastures in the Shepparton Irrigation Region sodify with time under ‘conjunctive water use’. We review evidence for adverse effects of such sodification on soil physical properties affecting plant productivity and hydrologic processes important in the long-term sustainability of the strategy. On-farm management implications of the strategy are discussed and important issues for research are identified.
8
Stevens, Craig, Won Sang Lee, Giannetta Fusco, Sukyoung Yun, Brett Grant, Natalie Robinson, and Chung Yeon Hwang. "The influence of the Drygalski Ice Tongue on the local ocean." Annals of Glaciology 58, no. 74 (April 2017): 51–59. http://dx.doi.org/10.1017/aog.2017.4.
Повний текст джерелаАнотація:
ABSTRACT The Drygalski Ice Tongue presents an ~80 km long floating obstacle to alongshore flows in the Victoria Land coastal ocean region of the Western Ross Sea. Here we use oceanographic data from near to the tongue to explore the interplay between the floating glacier and the local currents and stratification. A vessel-based circuit of the glacier, recording ocean temperature and salinity profiles, reveals the southwest corner to be the coldest and most complex in terms of vertical structure. The southwest corner structure beneath the surface warm, salty layer sustains a block of very cold water extending to 200 m depth. In this same location there was a distinct layer at 370 m not seen anywhere else of water at ~−1.93°C. The new observations broadly, but not directly, support the presence of a coherent Victoria Land Coastal Current. The data suggest the northward moving coastal current turns against the Coriolis force and works its way anticlockwise around the glacier, but with leakage beneath the glacier through the highly ‘rippled’ underside, resulting in a spatially heterogeneous supply to the Terra Nova Bay Polynya region – an important location for the formation of high-salinity shelf water.
9
Robinson, Randall W., Paul I. Boon, and Paul Bailey. "Germination characteristics of Melaleuca ericifolia Sm. (swamp paperbark) and their implications for the rehabilitation of coastal wetlands." Marine and Freshwater Research 57, no. 7 (2006): 703. http://dx.doi.org/10.1071/mf06006.
Повний текст джерелаАнотація:
Swamp paperbark, Melaleuca ericifolia Sm., is a small, clonal tree that occupies fresh- and brackish-water wetlands across south-eastern Australia. Seeds collected from Dowd Morass, a secondary-salinised Ramsar-listed wetland of the Gippsland Lakes region in eastern Victoria, showed very low viability (< 6%), with less than 50% of the seeds germinating even under ideal laboratory conditions. Greatest germination occurred with surface-sown seeds, germinated in darkness at a mean temperature of 20°C and salinity < 2 g L–1. At 20°C, maximum germination occurred at a salinity of 1 g L–1; germination fell rapidly at a near constant rate with increasing salinity. Lower temperatures, while moderating the inhibitory effects of salinity, markedly reduced germination; higher temperatures increased the inhibitory effects of salinity and light and reduced overall germination rates. Seeds subjected to brief inundation with saline water germinated rapidly if flushed by, and subsequently grown under, freshwater conditions. Specific timing of management interventions, particularly manipulations of water regime to control salinity regimes, are required if germination of M. ericifolia on the landscape scale is to be successful. Even so, the low overall viability of the seeds would present difficulties to large-scale, seed-based rehabilitation efforts.
10
McLean, R., and P. McManamon. "An innovative approach to small town water quality improvements." Water Supply 3, no. 3 (June 1, 2003): 209–14. http://dx.doi.org/10.2166/ws.2003.0028.
Повний текст джерелаАнотація:
Innovative solutions are required to meet the conflicting criteria of service level, community need, community desire, cost and risk to the supply authority in the delivery of water quality improvements to small regional communities. Grampians Region Water Authority services 74 towns in North-Western Victoria, an area of generally low rainfall, sparse settlement and few natural waterways. Town populations range from 10 to 13,000, with 56 towns having less than 500 people. A Water Quality Improvement Plan was recently developed by Grampians Water to address these natural difficulties. The plan examined a broad range of alternatives beyond the single-pipe reticulated supply system, including dual-pipe reticulation, rainwater sources and household water treatment systems for achieving target quality levels. The key findings were:• regional treatment plants are not economical if towns are more than 25 km apart• salinity is a major influence on strategy• for low salinity supplies, conventional treatment is most economical• for marginal salinity supplies, a two stage process involving conventional treatment and desalination is appropriate• desalination provides a total solution for high salinity groundwater supplies• drinking quality can only be economically achieved in very small towns by using household treatment of rainwater in a dual supply system. The resultant strategies and implementation issues outlined reveal some significant variations to the conventional approach.
11
Rovira, AD. "Dryland mediterranean farming systems in Australia." Australian Journal of Experimental Agriculture 32, no. 7 (1992): 801. http://dx.doi.org/10.1071/ea9920801.
Повний текст джерелаАнотація:
The mediterranean region of Australia extends from Geraldton in Western Australia across southern Australia into western and northern Victoria. This region experiences hot, dry summers and cool, wet winters, with 300-600 mm annual rainfall. In the dryland farming zone, the cereal-livestock farming system dominates and produces 30-35% of Australia's total agricultural production. The major soils in the region are deep, coarse-textured sands and sandy loams, duplex soils with coarse-textured sands over clay (generally low in nutrients and organic matter), and fine-textured red-brown earths of low hydraulic conductivity. Major soil problems in the region include sodicity, salinity, soil structural degradation, nutrient deficiencies, boron toxicity, acidity, waterlogging, inadequate nitrogen nutrition, water-repellence, and root diseases. These problems have been exacerbated by excessive clearing of trees, increased frequency of cropping, reduced area sown to pastures, declining pasture production, and a decline in nutrient levels. With improved soil management there is potential for increased productivity from dryland farming areas of the region and improved ecological sustainability.
12
Myers, BA, DH Ashton, and JA Osborne. "The Ecology of the Mallee Outlier of Eucalyptus behriana F. Muell. Near Melton, Victoria." Australian Journal of Botany 34, no. 1 (1986): 15. http://dx.doi.org/10.1071/bt9860015.
Повний текст джерелаАнотація:
An outlier of mallee vegetation occurs south of the Great Dividing Range in Victoria in a rain shadow region (annual rainfall approx. 500 mm) about 50 km west of Melbourne. A Eucalyptus behriana open-scrub with a sparse understorey of chenopods, mosses, lichens and some grasses occurs on solonetz soil on lateritized Tertiary sandy clays and on skeletal soils on Ordovician slates and sandstones. The dryness of the mallee site is probably exacerbated by the smaller rate of water infiltration and greater salinity of the solonetz soil under E. behriana compared with the solodic soil, in the moister area further north, under an open-forest of E. microcarpa. The multistemmed habit of E. behriana appears to be partly genetically fixed. Hollow lignotuberous rings, filled to a depth of about 15-25 cm with brown, nutrient-rich humus, are common. Pattern analysis of the distribution of stems of E. behriana indicated strong clumping at about 9 m², due to the multistemmed habit, and weaker clumping at about 600 m², which correlated with the size of groups of dense, spindly individuals of E. behriana, resulting from a past phase of gap regeneration.
13
Dugan, H. A., P. T. Doran, B. Wagner, F. Kenig, C. H. Fritsen, S. Arcone, E. Kuhn, N. E. Ostrom, J. Warnock, and A. E. Murray. "27 m of lake ice on an Antarctic lake reveals past hydrologic variability." Cryosphere Discussions 8, no. 4 (July 23, 2014): 4127–58. http://dx.doi.org/10.5194/tcd-8-4127-2014.
Повний текст джерелаАнотація:
Abstract. Lake Vida, located in Victoria Valley, is one of the largest lakes in the McMurdo Dry Valleys. Unlike other lakes in the region, the surface ice extends at least 27 m, which has created an extreme and unique habitat by isolating a liquid-brine with salinity of 195 g L−1. Below 21 m, the ice is marked by well-sorted sand layers up to 20 cm thick, within a matrix of salty ice. From ice chemistry, isotopic abundances of 18O and 2H, ground penetrating radar profiles, and mineralogy, we conclude that the entire 27 m of ice formed from surface runoff, and the sediment layers represent the accumulation of fluvial and aeolian deposits. Radiocarbon and optically stimulated luminescence dating limit the maximum age of the lower ice to 6300 14C yr BP. As the ice cover ablated downwards during periods of low surface inflow, progressive accumulation of sediment layers insulated and preserved the ice and brine beneath; analogous to the processes that preserve shallow ground ice. The repetition of these sediment layers reveals climatic variability in Victoria Valley during the mid- to late Holocene. Lake Vida is an excellent Mars analog for understanding the preservation of subsurface brine, ice and sediment in a cold desert environment.
14
Bluhm, Bodil A., Kristina Brown, Lina Rotermund, William Williams, Seth Danielsen, and Eddy C. Carmack. "New distribution records of kelp in the Kitikmeot Region, Northwest Passage, Canada, fill a pan-Arctic gap." Polar Biology 45, no. 4 (March 1, 2022): 719–36. http://dx.doi.org/10.1007/s00300-022-03007-6.
Повний текст джерелаАнотація:
AbstractKelps play important roles in ecosystems as they provide structural habitat and protection, and supply food. Given these beneficial roles and observed increases in seaweed biomass and distribution ranges across the Arctic, mapping kelp occurrence around Arctic coasts is both timely and necessary for future conservation. Here, we fill spatial gaps in the knowledge of kelp distribution in the southern Northwest Passage, Canadian Arctic Archipelago; specifically, we report the occurrence of Laminaria solidungula, Saccharina latissima and Alaria esculenta from Victoria and Dease straits and Bathurst Inlet in the Kitikmeot Region at depths mostly from 10 to 30 m (max. 40 m; upper extent vessel-limited). Kelp specimens were found at bottom water temperatures from sub-zero to 1 °C (surface-T to ~ 6 °C) and bottom water salinities of ~ 28 (surface-S < 20) in August–September. Kelp sites were characterized by both strong tidal currents (max. estimates from a tidal model 20–70 cm s−1 in center of passages) and hard substrates, interspersed with finer sediments. Co-occurring identifiable epibenthos was dominated by suspension-feeders preferring currents (sea cucumbers, soft corals, Hiatella clams), potential kelp consumers (sea urchins Strongylocentrotus sp., Margarites snails, limpets) and predatory invertebrates (sea stars, lyre crabs). At the same and some deeper nearby sites, loose kelp fragments were also found at the seabed, suggesting that kelps contribute to the regional detrital food web by supplying carbon to less productive sites. Kelps in the region may expand their ranges and/or growing season with reduced ice cover and warming, although constraints through local turbidity sources, extreme temperatures, low salinity and low nutrient concentrations are also recognized.
15
Prosser, IP, KJ Hailes, MD Melville, RP Avery, and CJ Slade. "A comparison of soil acidification and aluminum under Eucalyptus forest and unimproved pasture." Soil Research 31, no. 3 (1993): 245. http://dx.doi.org/10.1071/sr9930245.
Повний текст джерелаАнотація:
A comparison was made of pH (1:5, soil: 0.01 M CaCl2) and easily extractable forms of Al [0.01 M CaCl2 (Alca); 1 M KCl (AlK); and 0.05 M CuCl2 (AlCu)] between forest and pasture soils near Bendigo, Victoria. Perennial pasture growth is required in this region to reduce groundwater recharge as part of the management of dryland salinity, but pasture growth may be inhibited by Al and Mn toxicity as a consequence of soil acidification. Both forest and pasture soils were found to be acidic (mean pH of 4.0 and 4.3 respectively) and AlCa concentrations are sufficient to anticipate toxicity to sensitive species. The forest site was cleared of timber over 50 years ago, and has since acidified by 63 kmol H+ ha-1, which is accounted for by organic anion accumulation in the forest regrowth. The forest soil has lower concentrations of AlCa, for a given pH, and more Al complexed to organic matter (Alcu-AlK), even though forest and pasture soils have equal amounts of organic carbon. The different A1 concentrations in forest and pasture soils are accounted for by a lag in A1 response to acidification, and greater complexation of Al with organic matter in the forest soil.
16
McDonald, G. K., J. D. Taylor, A. Verbyla, and H. Kuchel. "Assessing the importance of subsoil constraints to yield of wheat and its implications for yield improvement." Crop and Pasture Science 63, no. 12 (2012): 1043. http://dx.doi.org/10.1071/cp12244.
Повний текст джерелаАнотація:
Many of the soils in the Australian cereal belt have subsoils with chemical and physical properties that restrict root growth, which limits water use and yield. On alkaline sodic soils salinity, high pH, high available boron (B), deficiencies of zinc (Zn) and manganese (Mn) and high soil strength occur commonly and aluminium (Al) toxicity restricts root growth on acid soils. While the effects of individual subsoil constraints have been studied there is some debate about the relative importance to yield of the different soil stresses across the region. To address this issue yield variation among a set of 52 varieties of bread wheat was analysed using yield data from 233 trials conducted over 12 years. The trials were conducted in all mainland States but the majority were in South Australia and Western Australia. Each variety was characterised for its response to high B, high pH, Al toxicity, salinity, deficiencies in Zn and Mn and resistance to root lesion nematode (Pratylenchus neglectus), root growth through strong soil, seminal root angle, carbon isotope discrimination (CID) and maturity. This data was then used to examine the contribution of each trait to the genetic variation in yield at each of the 233 trials. The contribution of a specific trait to the genetic variation in yield at each site was used to infer the importance of a particular constraint to yield at that site. Of the traits linked to soil constraints, salinity tolerance, (measured by Na+ exclusion) was most often associated with genetic variation in grain yield (34% of all experiments), followed by tolerance to high Al (26%) and B tolerance (21%). Tolerance to low Zn and Mn were not consistently associated with yield variation. However, maturity was the trait that was most frequently associated with yield variation (51% of experiments), although the relative importance of early and late flowering varied among the States. Yield variation was largely associated with early flowering in Western Australia and the relative importance of late flowering increased as trials moved eastward into South Australia, Victoria and New South Wales. Narrow, rather than wide, seminal root angle was more commonly associated with high yield (25% of sites) and there was little evidence of any regional pattern in the importance of root angle. CID was important in 18% of trials with a low CID being most commonly associated with high yields. The yield advantage at sites where a trait contributed significantly to yield variation ranged from ~15% for Na+ exclusion and B tolerance to 4% for tolerance to high pH. The analysis has provided an assessment of the relative importance of a range of traits associated with adaptation to environments where subsoil constraints are likely to affect yield and has indicated patterns in the importance and effects of these traits that may be linked to regional variation in rainfall and soils.
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Sadras, Víctor, David Roget, and Garry O'Leary. "On-farm assessment of environmental and management constraints to wheat yield and efficiency in the use of rainfall in the Mallee." Australian Journal of Agricultural Research 53, no. 5 (2002): 587. http://dx.doi.org/10.1071/ar01150.
Повний текст джерелаАнотація:
The responses of wheat grain yield to soil properties, weather, root diseases, and management practices were investigated in 75 grower-managed crops in the Mallee region of South Australia, Victoria, and New South Wales during 3 growing seasons. Fourteen cultivars were represented in the sampled crops, with Frame being the most common (56%). The most widespread crop sequence was wheat after pasture (43% of wheat crops), followed by wheat after fallow or cereal (both about 20%); 12% of the wheat was sown after legumes. Wheat after cereal was more common in drier sites, and wheat after fallow in wetter sites. Wheat yield was proportional to Fischer’s photothermal coefficient around flowering, and ranged from nil to 4.7 t/ha. On average, wheat crops sown after cereals yielded 0.4 t/ha less than their counterparts sown after fallow, and 0.7 t/ha less than those after legumes. Sowing date ranged from 24 April to 21 July; yield declined with delayed sowing at an average rate of 17 kg/ha.day. Growing season rainfall (April–October) ranged from 111 to 266 mm, and accounted for 27% of the variation in grain yield. Soil water content at sowing (0–1 m) ranged from 32 to 330 mm; yield increased with initial soil water at an average rate of 6 kg/ha.mm. Grain yield per unit growing season rainfall was generally low, with 75% of crops producing <12 kg grain/ha.mm; the maximum ratio was 21 kg/ha.mm. Soil constraints, including sodicity, alkalinity, salinity, and boron toxicity, reduced yield in part by reducing availability of stored soil water. Owing to severity of chemical constraints increasing with soil depth, grain yield and yield per unit growing season rainfall were both inversely related to the proportion of water stored deeper in the soil (0.5–1 m). Yield was unrelated to nitrogen, both initial and applied. Larger amounts of nitrogen accumulated in soils with more severe constraints partially accounted for the lack of association between yield and nitrogen.