• Authors:
    • Basnyat, P.
    • Liu, P.
    • Lemke, R.
    • Janzen, H.
    • Campbell, A.
    • Gan, T.
    • McDonald, C. L.
  • Source: Canadian Journal of Plant Science
  • Volume: 89
  • Issue: 5
  • Year: 2009
  • Summary: Crop roots transport water and nutrients to the plants, produce nutrients when they decompose in soil, and provide organic C to facilitate the process of C sequestration in the soil. Many studies on these subjects have been published for cereal crops, but little is known for oilseed and pulse crops. This study was conducted at Swift Current, Saskatchewan, in 2006 and 2007 to characterize the root growth and distribution profile in soil for selected oilseed and pulse crops. Three oilseed [canola ( Brassica napus L.), mustard ( Brassica juncea L.), flax ( Linum usitatissimum L.)], three pulse crops [chickpea ( Cicer arietinum L), dry pea ( Pisum sativum L.) lentil ( Lens culinaris Medik.)], and spring wheat ( Triticum aestivum L.) were grown in 100 cm deep * 15 cm diameter lysimeters pushed into a silt loam soil. Crops were studied under rainfed and irrigated conditions. Lysimeters were removed from the field and sampled for above-ground (AG) and root mass at different depths at five growth stages. Root mass was highest for canola (1470 kg ha -1) and wheat (1311 kg ha -1), followed by mustard (893 kg ha -1) and chickpea (848 kg ha -1), and was lowest for dry pea (524 kg ha -1) and flax (440 kg ha -1). The root mass of oilseeds and pulses reached a maximum between late-flowering and late-pod stages and then decreased to maturity, while wheat root mass decreased to maturity after reaching a maximum at boot stage. On average, about 77 to 85% of the root mass was located in the 0-40 cm depth. Canola, mustard, and wheat rooted to 100 cm, while the pulses and flax had only 4 to 7% of the root mass beyond the 60 cm depth. Irrigation only increased root mass in the 0-20 cm depth. Roots developed more rapidly than AG biomass initially, but the ratio of root biomass to AG biomass decreased with plant maturity. At maturity, the ratio of root biomass to AG biomass was 0.11 for dry pea, and between 0.20 and 0.22 for the other crops tested. Our findings on rooting depths and root mass distribution in the soil profile should be useful for modelling water and nutrient uptake by crops, estimating C inputs into soil from roots, and developing diverse cropping systems with cereals, oilseeds and pulses for semiarid environments.
  • Authors:
    • Berzy, T.
    • Hegyi, Z.
  • Source: Cereal Research Communications
  • Volume: 37
  • Issue: Suppl. 1
  • Year: 2009
  • Summary: If maize production is to be successful it is essential to be clear about the intended end-use and the farm conditions in order to make a wise choice of variety and technology. Recommendations on the end-use of the varieties can only be made based on knowledge of both yield levels and chemical quality. A total of 96 hybrids from four FAO maturity groups were examined at four locations in 2008 in order to analyse their yield and quality and to determine the effect of ecological factors on a number of parameters. The highest yield averages were recorded for hybrids in the FAO 300 group (12.95 t ha -1) at locations with the highest rainfall (Debrecen). In Debrecen and Iregszemcse the plants were able to develop a second ear, thus increasing the yield average (12.31 t ha -1, 11.75 t ha -1). In Szarvas irrigation helped to achieve good yields and reduce drought damage (10.97 t ha -1), while in Martonvasar, although rainfall sums were adequate, the uneven distribution and atmospheric drought led to lower yields (9.65 t ha -1). In this experiment, early hybrids (FAO, 200, FAO 300) had the best yield stability. The starch content of the grain exhibited a close correlation with the yield average. The greatest starch incorporation was recorded for FAO 300 hybrids (72.86%). The expected negative correlation between starch content and protein/oil content was observed. The FAO 200 hybrids had the highest protein and oil contents (9.70 and 3.89%), which gradually declined at later maturity dates (FAO 500: 9.14 and 3.51%). The thousand-kernel mass and the length of the main ear were closely correlated with the maturity date, being lowest for the earliest hybrids (326.39 g, 18.91 cm) and highest in the latest group (346.91 g, 19.74 cm). For protein and oil content, genetic differences between the hybrids were greater (1.50, 1.00%) than between locations (0.97, 0.82%), while in the case of starch the latter caused greater differences (2.84, 4.06%).
  • 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:
    • 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:
    • Filippi, F.
    • Magnani, G.
    • Bertolacci, M.
  • Source: Colture Protette
  • Volume: 38
  • Issue: 11
  • Year: 2009
  • Summary: The behaviour of two new black biodegradable mulching films (Mater-BI) was checked on cauliflower (Brassicaoleracea var. botrytis L.), comparing them to a traditional ldpe film and naked soil and at different irrigation systems (dripping irrigation, spray irrigation, without irrigation). The results showed that the water wasted reached the highest values in naked soil and the lowest in the ldpe film, while biodegradable films showed middle values. They also presented excellent results both for plant's growth and production, even higher than ldpe. About the degradation, both the biodegradable films showed good mechanical properties till the end of the cycle, with differences among the irrigation systems: degradation was faster under spray irrigation especially for the MB commercial film. Dripping irrigation was the best for production, soil humidity and film degradation.
  • Authors:
    • Service, R. F.
  • Source: Science
  • Volume: 326
  • Issue: 5952
  • Year: 2009
  • Summary: At first blush, it's easy to make the case for biofuels. By converting crops into ethanol or biodiesel, farmers can reduce demand for imported oil, lower national dependence on authoritarian governments in the Middle East, and potentially cut greenhouse gas emissions. But dig a little deeper, and the story gets more complicated. Biofuels promise energy and climate gains, but in some cases, those improvements wouldn't be dramatic. And they come with some significant downsides, such as the potential for increasing the price of corn and other food staples. Now, a series of recent studies is underscoring another risk: A widespread shift toward biofuels could pinch water supplies and worsen water pollution. In short, an increased reliance on biofuel trades an oil problem for a water problem.
  • Authors:
    • USDA
  • Year: 2009
  • Authors:
    • Six, J.
    • van Kessel, C.
    • Fonte, S. J.
    • Kong, A. Y. Y.
  • Source: Soil & Tillage Research
  • Volume: 104
  • Issue: 2
  • Year: 2009
  • Summary: Few studies address nutrient cycling during the transition period (e.g., 1-4 years following conversion) from standard to some form of conservation tillage. This study compares the influence of minimum versus standard tillage on changes in soil nitrogen (N) stabilization, nitrous oxide (N2O) emissions, short-term N cycling, and crop N use efficiency 1 year after tillage conversion in conventional (i.e., synthetic fertilizer-N only), low-input (i.e., alternating annual synthetic fertilizer- and cover crop-N), and organic (i.e., manure- and cover crop-N) irrigated, maize-tomato systems in California. To understand the mechanisms governing N cycling in these systems, we traced N-15-labeled fertilizer/cover crop into the maize grain, whole soil, and three soil fractions: macroaggregates (>250 mu m), microaggregates (53-250 mu m) and silt-and-clay (<53 mu m). We found a cropping system effect on soil N-new (i.e., N derived from N-15-fertilizer or - N-15-cover crop), with 173 kg N-new ha(-1) in the conventional system compared to 71.6 and 69.2 kg N-new ha(-1) in the low-input and organic systems, respectively. In the conventional system, more N-new was found in the microaggregate and silt-and-clay fractions, whereas, the N-new of the organic and low-input systems resided mainly in the macroaggregates. Even though no effect of tillage was found on soil aggregation, the minimum tillage systems showed greater soil fraction-N-new than the standard tillage systems, suggesting greater potential for N stabilization under minimum tillage. Grain-N-new was also higher in the minimum versus standard tillage systems. Nevertheless, minimum tillage led to the greatest N2O emissions (39.5 g (NO)-O-2-N ha(-1) day(-1)) from the conventional cropping system, where N turnover was already the fastest among the cropping systems. In contrast, minimum tillage combined with the low-input system (which received the least N ha(-1)) produced intermediate N2O emissions, soil N stabilization, and crop N use efficiency. Although total soil N did not change after 1 year of conversion from standard to minimum tillage, our use of stable isotopes permitted the early detection of interactive effects between tillage regimes and cropping systems that determine the trade-offs among N stabilization, N2O emissions, and N availability. (C) 2009 Elsevier B.V. All rights reserved.
  • Authors:
    • Baraibar, B.
    • Westerman, P. R.
    • Recasens, J.
  • Source: Journal of Applied Ecology
  • Volume: 46
  • Issue: 2
  • Year: 2009
  • Summary: Agricultural intensification can cause a huge increase in productivity. However, associated costs in terms of reduced, self-regulation and increased reliance on external inputs for the control of pests, diseases and weeds are seldom taken into account or acknowledged. A pro-active approach in which ecosystems services are documented and potential effects of changes in agricultural practices evaluated may lead to more informed decisions prior to implementation. We investigated the effects of management of cereal production in a semi-arid region on weed seed mortality caused by predators. Seed losses have a greater impact on weed population size than any other life cycle process and should therefore be of significance for natural weed control. We hypothesized that the conversion from rain-fed to irrigated production should lead to reduced and the adoption of no-till techniques to increased seed predation. Seed removal and seed predator populations were monitored in irrigated (N = 3) and rain-fed cereal fields (N = 6) and field margins. Of the dryland fields half was conventionally tilled and the other half no-till. Seed removal (g g(-1) 2-days(-1)) was followed from April 2007 until June 2008, using Petri-dishes and exclosure cages. Populations of harvester ants were estimated by direct nest counts; rodent populations by Sherman live traps. Seed removal in dryland cereals, mainly by harvester ants Messor barbarus was high from mid April to mid October, and should cause a strong weed suppressive effect. Seed removal in irrigated cereals, mainly by granivorous rodents Mus spretus, was low. Seed removal was higher in no-till than in conventional fields and corresponded to differences in harvester ant nest densities. Synthesis and applications. Our results show that tillage and irrigation in a semi-arid cereal production system results in a reduction and total annihilation of granivorous harvester ants, respectively. The concurrent decline in weed seed mortality could lead to increased herbicide use and dependency. In particular, in areas where economic margins are small or the environmental costs of tillage and irrigation high, the increased costs of chemical weed control may exceed the benefits. Here, preserving biodiversity to enhance natural weed control is a viable alternative to agricultural intensification.