• Authors:
    • Nogueira, C. C. P.
    • Veloso, M. E. da C.
    • Freire Filho, F. R.
    • Cardoso, M. J.
    • Blanco, F. F.
    • Dias, N. da S.
  • Source: Pesquisa Agropecuária Brasileira
  • Volume: 46
  • Issue: 5
  • Year: 2011
  • Summary: The objective of this work was to evaluate the response of green maize ( Zea mays) intercropped with cowpea ( Vigna unguiculata) to irrigation depths and phosphorus doses. The experiments were carried out in 2008 and 2009 in a randomized block design, with 25 treatments and four replicates. Treatments consisted of five irrigation depths at 70, 110, 140, 180 and 220% of the crop evapotranspiration, and of five doses of P 2O 5: 0, 50, 100, 150 and 200% of the recommended P dose. Maize was sown at 0.80*0.40 m spacing, and cowpea was planted inside the lines among maize plants. There was no effect of P 2O 5 doses, but the response to irrigation depths was quadratic for maize and linear for cowpea. The maximum technical yield of green ears of maize with straw (10.76 Mg ha -1) and without straw (7.62 Mg ha -1) was obtained with 530 mm depth, intermediary to the 180 and 220% of the crop evapotranspiration. The highest cowpea green grain (3.40 Mg ha -1) was obtained with the highest water depth, of 644 mm.
  • Authors:
    • Kukal, S. S.
    • Christen, E. W.
    • Hira, G. S.
    • Balwinder-Singh
    • Sudhir-Yadav
    • Sharma, R. K.
    • Humphreys, E.
  • Source: Advances in Agronomy
  • Volume: 109
  • Year: 2010
  • Summary: Increasing the productivity of the rice-wheat (RW) system in north-west India is critical for the food security of India. However, yields are stagnating or declining, and the rate of groundwater use is not sustainable. Many improved technologies are under development for RW systems, with multiple objectives including increased production, improved soil fertility, greater input use efficiency, reduced environmental pollution, and higher profitability for farmers. There are large reductions in irrigation amount with many of these technologies compared with conventional practice, such as laser land leveling, alternate wetting and drying (AWD) water management in rice, delayed rice transplanting, shorter duration rice varieties, zero till wheat, raised beds, and replacing rice with other crops. However, the nature of the irrigation water savings has seldom been determined. It is often likely to be due to reduced deep drainage, with little effect on evapotranspiration (ET). Reducing deep drainage has major benefits, including reduced energy consumption to pump groundwater, nutrient loss by leaching, and groundwater pollution. The impacts of alternative technologies on deep drainage (and thus on irrigation water savings) vary greatly depending on site conditions, especially soil permeability, depth to the watertable, and water management. More than 90% of the major RW areas in north-west India are irrigated using groundwater. Here, reducing deep drainage will not "save water" nor reduce the rate of decline of the watertable. In these regions, it is critical that technologies that decrease ET and increase the amount of crop produced per amount of water lost as ET (i.e., crop water productivity, WP ET) are implemented. The best technologies for achieving this are delaying rice transplanting and short duration rice varieties. The potential for replacing rice with other crops with lower ET is less clear.
  • Authors:
    • Kadasrivenkata, H.
    • Kapanigowda, M.
    • Stewart, B. A.
    • Howell, T. A.
    • Baumhardt, R. L.
  • Source: Field Crops Research
  • Volume: 118
  • Issue: 2
  • Year: 2010
  • Summary: Under dryland conditions of the Texas High Plains, maize ( Zea mays) production is limited by sparse and erratic precipitation that results in severe water stress particularly during grain formation. When plant populations are reduced to 2.0-3.0 plants m -2 to conserve soil water for use during grain filling, tillers often form during the vegetative growth and negate the expected economic benefit. We hypothesized that growing maize in clumps spaced 1.0 m apart would reduce tiller formation, increase mutual shading among the plants, and conserve soil water for grain filling that would result in higher grain yield. Studies were conducted during 2006 and 2007 at Bushland, TX. with two planting geometries (clump vs. equidistant), two irrigation methods (low-energy precision applicator, LEPA, and low-elevation spray applicator, LESA) at three irrigation levels (dryland, 75 mm and 125 mm in 2006; and dryland, 50 mm and 100 mm in 2007). For dryland plots in 2007, clump plants had only 0.17 tillers (0.66 tillers m -2) compared with 1.56 tillers per plant (6.08 tillers m -2) for equidistant spacing. Tillers accounted for 10% of the stover for the equidistant plants, but less than 3% of the grain. Clump planting produced significantly greater grain yields (321 g m -2 vs. 225 g m -2 and 454 g m -2 vs. 292 g m -2 during 2006 and 2007, respectively) and Harvest Indexes (0.54 vs. 0.49 and 0.52 vs. 0.39 during 2006 and 2007, respectively) compared with equidistant plants in dryland conditions. Water use efficiency (WUE) measurements in 2007 indicated that clumps had a lower evapotranspiration (ET) threshold for initiating grain production, but the production function slopes were 2.5 kg m -3 for equidistant treatments compared to 2.0 kg m -3 for clump treatments. There was no yield difference for method of irrigation on water use efficiency. Our results suggest that growing maize in clumps compared with equidistant spacing reduced the number of tillers, early vegetative growth, and Leaf Area Index (LAI) so that more soil water was available during the grain filling stage. This may be a useful strategy for growing maize with low plant populations in dryland areas where severe water stress is common.
  • Authors:
    • Lecler, N. L.
    • Tweddle, P. B.
  • Source: Proceedings of the Annual Congress - South African Sugar Technologists' Association
  • Issue: 83
  • Year: 2010
  • Summary: Many guidelines and recommendations for sugarcane farming are aimed at achieving a large number of ratoon crops. One of the reasons for this is that the replanting costs can be considerable when a field is conventionally tilled and replanted. Thus, delaying reestablishment makes financial sense provided the cost savings are greater than any yield and revenue penalties. An alternative is to introduce a controlled traffic and zero-till farming system (CTF), thereby lowering re-establishment costs and potentially allowing for fewer ratoon crops and more frequent green manure or break crops. A rigorous yield, sucrose content, costing and cash-flow analysis, based on published research findings and detailed costing of representative machinery, showed that a CTF system with only three ratoon crops was far more profitable than a conventional farming system involving eight ratoon crops and more intensive tillage operations. A doubling in profitability was shown when the yield benefits reported with break crops and the yield decline rates reported under conventional farming systems were included in the analysis. Substantial gains in water use productivity were also shown, up to nearly 80% improvement over a conventional farming system. Adoption of a CTF system with only three ratoon crops is therefore highly recommended and should be taken very seriously by decision-makers in the sugarcane industry.
  • Authors:
    • Wallender, W. W.
    • Burger, M.
    • Horwath, W. R.
    • Mailapalli, D. R.
  • Source: Agricultural Water Management
  • Volume: 98
  • Issue: 1
  • Year: 2010
  • Summary: Farming practices, including tillage, cover cropping and residue management can have profound effects on the efficiency of irrigation practices. The effects of three field management practices (FMPs) standard tillage and winter-fallow (ST), standard tillage and winter-cover crop (STCC), and no-till and winter-fallow (NT) and two field lengths (122 and 366 m) on runoff and export of dissolved organic carbon (DOC) were investigated in a furrow-irrigated cropping system over two years. The residue cover was 40, 32 and 11% in 2007, and 58, 61 and 11% in 2008 for STCC, NT and ST, respectively. Furrow irrigation experiments were conducted prior to crop planting following the cover crop. The inflow was kept constant across all treatments, and infiltration and runoff were estimated using a volume balance model (VBM). The DOC concentration tended to increase with increasing field length, but did not differ among the FMPs. A threefold increase in field length increased infiltration by 40%, and decreased runoff by 60-90% and DOC export by 65-83%. In both years, infiltration was highest in STCC. In NT, infiltration was lowest in 2007, which was likely due to soil sealing, and intermediate among the three FMPs in 2008 perhaps due to the increase in residue cover in the second year. The DOC budget analysis showed that fields and FMPs acted as DOC sinks exporting less DOC than was applied in the irrigation water. The results suggest that longer furrows and STCC were greater DOC sinks compared to ST and shorter field practices. The VBM, as applied in this study to estimate infiltration and runoff, could be used to predict optimal field length to minimize runoff and promote DOC adsorption to soil within the constraints of water quality and availability and soil conditions.
  • Authors:
    • Mohammed, S. M.
    • Fayed, T. A.
    • Esmail, A. F.
    • Abdou, N. A.
  • Source: The Bulletin of Faculty of Agriculture
  • Volume: 61
  • Issue: 1
  • Year: 2010
  • Summary: This investigation was carried out during the 2006 and 2007 growing seasons on a 3 year old Le-Conte pear trees ( Pyrus communis L. * Pyrus pyrifolia N.) grafted on Pyrus betulaefolia rootstock and planted at 5*5 meters apart (169 trees/faddan) in sandy soil under drip irrigation system, at El-Kassasien Horticultural Research Station, Ismailia Governorate. One source of organic fertilizers (compost) plus natural rocks (rock phosphate+feldspare), with or without biofertilizers (phosphorein and biogein) plus humic acid plus compost tea, were compared with chemical fertilization. Application of compost with biofertilizers plus humic add plus compost tea gave a better effect on all vegetative characteristics (growth rate of trunk diameter, shoot diameter, shoot length, number of leaves per shoot and leaf area) and chemical leaf constituents (leaf pigments, macro and micro elements, total carbohydrates, C/N ratio, protein contents) and yield compared to other organic treatments. Also vegetative growth, nutritional status and yield were significantly increased from the first till the second season indicating the accumulation effect of organic manure plus biofertilizers plus humic acid plus compost tea. Chemical fertilizer gave the highest vegetative and yield characteristics and leaf chemical contents compared to all organic rates with or without biofertilizers, humic acid and compost tea in the two seasons of study.
  • Authors:
    • Tomar, S. S.
    • Yadav, A. K.
    • Singh, A.
    • Pal, G.
    • Shahi, U. P.
    • Kumar, A.
    • Singh, B.
    • Gupta, R. K.
    • Naresh, R. K.
  • Source: Progressive Agriculture
  • Volume: 10
  • Issue: 2
  • Year: 2010
  • Summary: Resource conserving technologies (RCTs) with double no-till practices represents a major shift in production techniques for attaining optimal productivity, profitability and water use in rice-wheat system in Indo-Gangetic plains. Conventional tillage and crop establishment methods such as puddled transplanting in the ricewheat ( Oryza sativa L.- Triticum aestivum L.) system in the Indo-Gangetic Plains (IGP) require a large amount of water and labor, both of which are increasingly becoming scarce and expensive. We attempted to evaluate alternatives that would require smaller amounts of these two inputs. A field experiment was conducted in the Western IGP for 2 years to evaluate various tillage and crop establishment systems for their efficiency in labor, water, and energy use and economic profitability. The soil physical properties (bulk density, mean weight diameter of aggregates and infiltration rate) improved significantly compared to puddled transplanted rice-conventional till wheat system. The wide beds and double no-till with flat layouts in rice-wheat system is under evaluation in different scenario of soil, climate, crop cultivars and seeding/crop establishment techniques (direct seeding, transplanting) and showed non consistent results. Systematic information on various aspects of narrow/wide beds is lacking. The productivity of rice with wide beds was at par compared to reduced tillage transplanted rice layouts but, the wheat productivity was reverse as it was highest under wide beds. The RW system productivity was highest with wide raised beds does differ significantly with other tillage and crop establishment techniques except with mulch crop establishment techniques. The water productivity of both rice and wheat was markedly improved with wide beds compared to other tillage and crop establishment techniques. Under research managed trials (rice on double no-till flat) with basmati rice, the profitability was maximum with ZTDSR (US $ 505 ha -1) and was least with direct seeded on narrow raised beds (US$305 ha -1). The study showed that the conventional practice of puddled transplanting could be replaced with no-tillage-based crop establishment methods to save water and labor. However, the occurrence and distribution of rainfall during the cropping season had considerable influence on the savings in irrigation water.
  • Authors:
    • Schroeder, K. L.
    • Paulitz, T. C.
    • Schillinger, W. F.
  • Source: Plant Disease
  • Volume: 94
  • Issue: 1
  • Year: 2010
  • Summary: An irrigated cropping systems experiment was conducted for 6 years in east-central Washington State to examine agronomic and economic alternatives to continuous annual winter wheat ( Triticum aestivum) with burning and plowing, and to determine how root diseases of cereals are influenced by management practices. The continuous winter wheat treatment with burning and plowing was compared with a 3-year no-till rotation of winter wheat-spring barley ( Hordeum vulgare)-winter canola ( Brassica napus) and three straw management treatments: burning, straw removal, and leaving the straw stubble standing after harvest. Take-all disease and inoculum increased from years 1 to 4 in the continuous winter wheat treatment with burning and plowing, reducing plant growth compared to the no-till treatments with crop rotations. Inoculum of Rhizoctonia solani AG-8 was significantly lower in the tilled treatment compared to the no-till treatments. Inoculum concentration of Fusarium pseudograminearum was higher than that of F. culmorum, and in one of three years, the former was higher in treatments with standing stubble and mechanical straw removal compared to burned treatments. Residue management method had no effect on Rhizoctonia inoculum, but spring barley had more crown roots and tillers and greater height with stubble burning. This 6-year study showed that irrigated winter wheat can be produced in a no-till rotation without major disease losses and demonstrated how cropping practices influence the dynamics of soilborne cereal diseases and inoculum over time.
  • Authors:
    • Rensburg, L. D. van
  • Source: South African Journal of Plant and Soil
  • Volume: 27
  • Issue: 1
  • Year: 2010
  • Summary: This is the third soil physics review to be published in South African Journal of Plant and Soil. In the previous reviews the focus was broad and covered almost every aspect of the subject, providing a comprehensive list of contributions in soil physics. For the 25th year anniversary celebration of South African Journal of Plant and Soil, I have chosen to narrow the scope and focus on advances in soil physics in relation to irrigation and dryland agriculture. From a bio-physical viewpoint, South African researchers have made a major contribution to the body of scientific knowledge about irrigation and its application, expressed mainly in the form of irrigation or crop models such as PUTU, SWB and BEWAB. Attention was also given to modern ways of irrigation scheduling based on continuous soil water monitoring. Several irrigation scheduling service providers have adapted their businesses accordingly, with the result that South Africa is probably the leading country in Africa with respect to soil water monitoring and associated communication technology. In contrast, the review has shown that at farm and irrigation scheme level, salt management requires urgent attention. This is necessary as a precautionary measure to protect our natural resources. In the second part of the review the contribution of soil physics in relation to tillage practices is explored, and in particular how these have modified the field water balance components in order to enhance yield and rain water productivity. Based on the results of field experiments, new relationships were established, viz. rainfall and maize yield; water storage and yield; runoff and surface coverage by crop residue mulches; tillage depth, texture and yield relationships. Lastly, the review also showed how the water balance on clay and duplex soils in semi-arid zones can be modified through in-field rainwater harvesting to increase their rain water productivity. This technology has enhanced the livelihoods of many communal families who have applied the technique in their homesteads.
  • Authors:
    • Kennedy, A. C.
    • Schillinger, W. F.
    • Young, D. L.
    • Paulitz, T. C.
  • Source: Field Crops Research
  • Volume: 115
  • Issue: 1
  • Year: 2010
  • Summary: Field burning of residue is a traditional management tool for irrigated wheat ( Triticum aestivum L.) production in the Inland Pacific Northwest of the United States (PNW) that can result in reduced air quality. A 6-year no-till field experiment to evaluate two complete cycles of a 3-year irrigated crop rotation of winter wheat-spring barley ( Hordeum vulgare L.)-winter canola ( Brassica napus L.) was sown (i) directly into standing residue of the previous crop, (ii) after mechanical removal of residue and, (iii) after burning of residue. The traditional practice of continuous annual winter wheat sown after burning residue and inverting the topsoil with a moldboard plow was included as a check treatment. Over-winter precipitation storage efficiency (PSE) was markedly improved when residue was not burned or burned and plowed after grain harvest. Grain yield of winter wheat trended higher in all no-till residue management treatments compared to the check treatment. Average grain yields of spring barley and canola were not significantly different among the no-till residue management treatments. Winter canola failed in 5 of 6 years due to a combination of a newly identified Rhizoctonia damping-off disease caused by Rhizoctonia solani AG-2-1 and cold temperatures that necessitated replanting to spring canola. Six-year average net returns over total costs were statistically equal over all four systems. All systems lost from $358 to $396 ha -1. Soil organic carbon (SOC) increased linearly each year with no-till at the 0-5 cm depth and accumulated at a slower rate at the 5-10 cm depth. Take-all of wheat caused by Gaeumannomyces graminis var. tritici was most severe in continuous annual winter wheat. The incidence and severity of Rhizoctonia on roots of wheat and inoculum of R. solani AG-8, was highest in the no-till treatments, but there was no grain yield loss due to this disease in any treatment. Residue management method had no consistent effect on Rhizoctonia root rot on barley. The annual winter grass downy brome ( Bromus tectorum L.) was problematic for winter wheat in the standing and mechanically removed residue treatments, but was controlled in the no-till residue burned and the burn and plow check. Another winter annual grass weed, rattail fescue ( Vulpia myuros L.), infested all no-till treatments. This was the first comprehensive and multidisciplinary no-till irrigated crop rotation study conducted in the Pacific Northwest.