• Authors:
    • Erenstein, O.
  • Source: Agricultural Water Management
  • Volume: 96
  • Issue: 12
  • Year: 2009
  • Summary: The intensive irrigated rice-wheat systems in the northwest Indo-Gangetic Plains of South Asia are built on a long tradition of canal irrigation and the more recent advent of tubewells. Findings from farm surveys are used to examine water management and water productivity in the rice-wheat belt of India's Haryana State and Pakistan's Punjab province. Attributes of the irrigation sources help explain the widespread interest in groundwater use and the relative demise of canal water use. In each area groundwater now is the main irrigation source, used either solely or in conjunction with surface water. The ownership of tubewells is near universal among the surveyed farms, whereas conjunctive water use is more widespread during the monsoon season, among better endowed farmers and in the Pakistan Punjab. In Pakistan Punjab farmers primarily rely on diesel powered tubewells whereas Haryana farmers mainly use relatively cheaper electric power. Water productivity indicators for rice are markedly lower than those for wheat - largely reflecting significantly higher water inputs in paddy cultivation - but also vary between the study areas and by the prevailing water use, reflecting the limited incentives for farmers to use water wisely. A combination of technological, land use and market based approaches is likely to be most effective in achieving sustainable water management in these intensive cereal systems.
  • Authors:
    • Kelly,K.
    • Graham,J.
    • Biswas,W. K.
    • John,M. B.
  • Source: 6th Australian Conference on Life Cycle Assessment
  • Year: 2009
  • Authors:
    • Graham, J.
    • Kelly, K.
    • Armstrong, R.
    • Phillips, F.
    • Officer, S.
  • Source: Proceedings of Greenhouse 2009
  • Year: 2009
  • Authors:
    • Armstrong, R.
    • Graham, J.
    • Phillips, F. A.
    • Officer, S.
  • Source: Managing Climate Change MC2 Conference
  • Year: 2009
  • Authors:
    • Wu, J. Q.
    • Singh, P.
    • Flury, M.
    • Schillinger, W. F.
    • Huggins, D. R.
    • Stoeckle, C. O.
    • Al-Mulla, Y. A.
  • Source: Applied Engineering in Agriculture
  • Volume: 25
  • Issue: 1
  • Year: 2009
  • Summary: Establishing winter wheat in the dryland Pacific Northwest requires soil water at depths that the seeds are planted in the early fall. Usually, a soil mulch is created and maintained to conserve seed-zone water and to promote the early establishment of winter wheat. Unfortunately, the tillage used to create the soil mulch often results in unacceptable levels of wind erosion. Chemical (no-till) fallow (CF) and reduced-tillage fallow (RT) are two alternatives for reducing wind erosion, but their effectiveness in maintaining sufficient seed-zone water is unknown. Our objectives were to: (i) assess the effects of CF and RT on seed- and root-zone temperature and water; and (ii) test a model (Simultaneous Heat and Water, SHAW) for simulating management effects on soil temperature and water. Weather data, soil temperature, and water content were monitored in CF and RT treatments. The RT treatment was observed to retain more seed-zone water over summer compared to CF. During the wet winter, CF gained more water than RT. Observed soil temperatures were higher in the CF than in RT. SHAW-simulated water contents followed the trend of the field data, though it slightly under-predicted soil water content for CF and over-predicted for RT. We concluded that RT would provide more seed-zone water for winter wheat establishment than CF. In addition, the SHAW model proved adequate in simulating soil water and temperature, and therefore may serve as a useful modeling tool for evaluating tillage and residue management alternatives.
  • Authors:
    • Blignaut, J.
    • Ueckermann, L.
    • Aronson, J.
  • Source: South African Journal of Science
  • Volume: 105
  • Issue: 1/2
  • Year: 2009
  • Summary: South Africa in general has been approximately 2% hotter and at least 6% drier over the ten years between 1997 and 2006 compared to the 1970s. The use of water has also increased greatly over this same period. By 2000, 98.6% of that year's surface water yield and 41% of the annual utilisable potential of groundwater was allocated to use. Irrigation agriculture, comprising 60% of total consumption, is by far the largest single consumer of water. Given these climatic and water use changes as a backdrop, we employed a panel data econometric model to estimate how sensitive the nation's agriculture may be to changes in rainfall. Net agricultural income in the provinces, contributing 10% or more to total production of both field crops and horticulture, is likely to be negatively affected by a decline in rainfall, especially rain-fed agriculture. For the country as a whole, each 1% decline in rainfall is likely to lead to a 1.1% decline in the production of maize (a summer grain) and a 0.5% decline in winter wheat. These results are discussed with respect to both established and emerging farmers, and the type of agriculture that should be favoured or phased out in different parts of the country, in view of current and projected trends in climate, increasing water use, and declining water availability.
  • Authors:
    • Brown, S.
    • Westhoff, P.
  • Issue: 05-09
  • Year: 2009
  • Summary: This report incorporates higher energy prices estimated by CRA International under H.R. 2454 (The American Clean Energy and Security Act of 2009) on Missouri crop production costs. This analysis uses current 2009 Missouri crop production cost estimates as the base and examines the level of these production costs in 2020, 2030, 2040 and 2050 assuming these production costs change only as a result of the higher energy costs estimated by CRA International under H.R. 2454. Using the 11, 34 and 45 percent increases found by CRA International in motor fuel, natural gas and electricity prices, respectively, by 2050 as a result of H.R. 2454, estimated Missouri crop operating costs increase by 8.1, 8.8, 4.4 and 10.4 percent for dryland maize, irrigated maize, soyabeans and wheat, respectively.
  • Authors:
    • Hunt, J. R.
    • Dalgliesh, N. P.
    • McCown, R. L.
    • Whish, J. P. M.
    • Robertson, M. J.
    • Foale, M. A.
    • Poulton, P. L.
    • Rees, H. van
    • Carberry, P. S.
    • Hochman, Z.
  • Source: Crop & Pasture Science
  • Volume: 60
  • Issue: 11
  • Year: 2009
  • Summary: Crop simulation models relevant to real-world agriculture have been a rationale for model development over many years. However, as crop models are generally developed and tested against experimental data and with large systematic gaps often reported between experimental and farmer yields, the relevance of simulated yields to the commercial yields of field crops may be questioned. This is the third paper in a series which describes a substantial effort to deliver model-based decision support to Australian farmers. First, the performance of the cropping systems simulator, APSIM, in simulating commercial crop yields is reported across a range of field crops and agricultural regions. Second, how APSIM is used in gaining farmer credibility for their planning and decision making is described using actual case studies. Information was collated on APSIM performance in simulating the yields of over 700 commercial crops of barley, canola, chickpea, cotton, maize, mungbean, sorghum, sugarcane, and wheat monitored over the period 1992 to 2007 in all cropping regions of Australia. This evidence indicated that APSIM can predict the performance of commercial crops at a level close to that reported for its performance against experimental yields. Importantly, an essential requirement for simulating commercial yields across the Australian dryland cropping regions is to accurately describe the resources available to the crop being simulated, particularly soil water and nitrogen. Five case studies of using APSIM with farmers are described in order to demonstrate how model credibility was gained in the context of each circumstance. The proposed process for creating mutual understanding and credibility involved dealing with immediate questions of the involved farmers, contextualising the simulations to the specific situation in question, providing simulation outputs in an iterative process, and together reviewing the ensuing seasonal results against provided simulations. This paper is distinct from many other reports testing the performance and utility of cropping systems models. Here, the measured yields are from commercial crops not experimental plots and the described applications were from real-life situations identified by farmers. A key conclusion, from 17 years of effort, is the proven ability of APSIM to simulate yields from commercial crops provided soil properties are well characterised. Thus, the ambition of models being relevant to real-world agriculture is indeed attainable, at least in situations where biotic stresses are manageable.
  • Authors:
    • Davis, R. A.
    • Huggins, D. R.
    • Cook, R. J.
    • Paulitz, T. C.
  • Source: Canadian Journal of Plant Pathology
  • Volume: 31
  • Issue: 4
  • Year: 2009
  • Summary: Fusarium crown rot of wheat (Triticum aestivum), caused by Fusarium pseudograminearum and Fusarium culmorum, is a yield-limiting disease in the dryland wheat-production area of the intermountain Pacific Northwest and is exacerbated in water-stressed plants induced by overfertilizing with nitrogen (N). Plants with excess N deplete water from the soil profile more rapidly and become drought stressed prematurely. Traditionally a problem on winter wheat in summer fallow, this disease has become more important for spring wheat in continuous cropping areas managed for high grain protein levels. During 3 years with direct seeding (no till) near Pullman, Washington, we investigated whether a split application of N, with some applied the previous fall and some with planting, could limit the disease compared with all N applied in the spring and with no N as the check. We also investigated the influence of the previous (rotation) crop (winter and spring canola, Brassica rapa; barley, Hordeum vulgare; or peas, Pisum sativum) on disease, grain yield, grain protein concentration, and populations of Fusarium in the soil. Overall, the DNA concentration of F. culmorum was significantly greater than F. pseudograminearum, and F. culmorum was highest following spring barley. Disease severity and yield were consistently lower in the no-N treatments compared with the other N treatments. The split application reduced disease in only 1 of 3 years. The all-spring application resulted in higher grain protein in 2 of 3 years compared with the split application, but yield was not affected. The previous crop had small but significant effects on disease, but they were not consistent from year to year and often interacted with the N treatment. Grain protein was higher in wheat after pea in 2 of 3 years. In conclusion, splitting of N had little effect on fusarium crown rot, probably because the N level in both treatments was conducive for disease development. Even if not a host species, the previous crop had little effect on subsequent disease, probably because Fusarium persists for more than one season as chlamydospores and in crop residue in this dry summer climate.
  • Authors:
    • Gotosa, J.
    • Gwenzi, W.
    • Chakanetsa, S.
    • Mutema, Z.
  • Source: Nutrient Cycling in Agroecosystems
  • Volume: 83
  • Issue: 3
  • Year: 2009
  • Summary: In southern Africa, tillage research has focused on rainfed smallholder cropping systems, while literature on high-input irrigated cropping systems is limited. We evaluated the effects of conventional (CT), minimum (MT) and no-till (NT) tillage systems on soil organic carbon (SOC), bulk density, water-stable aggregates (WSA), mean weighted diameter (MWD) and crop yields in an irrigated wheat-cotton rotation. Soil data were monitored in the first and final year, while yields were monitored seasonally. Average bulk densities (1.5-1.7 Mg m -3) were similar among tillage systems, but often exceeded the critical limit (1.60 Mg m -3) for optimum root growth. Conversion from CT to MT and NT failed to ameliorate the high bulk densities associated with the alluvial soil. SOC (g kg -1) at 0-15 cm was higher ( P<0.05) under MT (3.9-5.8) and NT (4.2-5.6) than CT (2.9-3.3). Corresponding horizon SOC stocks (Mg C ha -1) for the tillage treatments were; 9.3-13.9 (MT), 9.3-13.5 (NT) and 7.3-7.7 (CT). In the final year, significant ( P<0.05) tillage effects on SOC stocks were also observed at 15-30 cm. Cumulative SOC stocks (Mg C ha -1) in the 0-60 cm profile were higher ( P<0.05) under MT (32.8-39.9) and NT (32.9-41.6) than CT (27.8-30.9). On average, MT and NT sequestered between 0.55 and 0.78 Mg C ha -1 year -1 at 0-30 cm depth, but a net decline (0.13 Mg C ha -1 year -1) was observed under CT. At 0-30 cm, MT and NT had higher ( P<0.05) MWD (0.19-0.23 mm) and WSA (2.3-3.5%) than CT (MWD: 0.1-0.12 mm, WSA: ~1.0%). Both MWD and WSA were significantly ( P<0.05) correlated to SOC. Seasonal yields showed significant ( P<0.05) tillage effects, but 6-year mean yields (t ha -1) were similar (CT: 4.49, MT: 4.33, NT: 4.32 for wheat; CT: 3.30, MT: 2.82, NT: 2.83 for cotton). Overall, MT and NT improved soil structural stability and carbon sequestration, while impacts on crop productivity were limited. Therefore, MT and NT are more sustainable tillage systems for the semi-arid regions than conventional tillage.