• Authors:
    • Silva, J. R. M. da
    • Silva, L. L.
    • Pisco, A. M. V.
    • Torres, C. J. V.
  • Source: International Conference on Agricultural Engineering
  • Year: 2010
  • Summary: Centre-pivot irrigation systems frequently cause surface runoff and erosion problems. This is more evident in complex topographies and low infiltrability soils. To overcome these problems farmers have tried different tillage systems, attaining different results, depending on soil type and irrigation management. Field tests, using small plots, were carried out in a Mediterranean soil with three different tillage systems: no-till, basin tillage and conventional tillage, as a control practice. Conventional tillage showed the highest runoff values (30% of collected water depth) with significant differences to no-till (15%) and basin tillage (2%). Maximum average values of sediment yields per irrigation event were lower for basin tillage (4.46 kg/ha) and no-till (9.59 kg/ha) compared to conventional tillage (23.45 kg/ha). The no-till system showed higher soil water content along all the irrigation season compared to the other two tillage systems. From a soil and water conservation point of view the basin tillage practice is the best option. But, from an economic point of view the no-till practice can be also a good option in these conditions.
  • Authors:
    • Heerden, P. S. van
    • Singels, A.
    • Rensburg, L. D. van
    • Annandale, J. G.
    • Jager, J. M. de
    • Inman-Bamber, N. G.
    • Durand, W.
    • Gree, G. C.
    • Crosby, C. T.
    • Schulze, R. E.
  • Source: South African Journal of Plant and Soil
  • Volume: 27
  • Issue: 1
  • Year: 2010
  • Summary: Mathematical simulation of crop growth and water relations has become indispensable to agricultural science and practice. A critical assessment of how modelling has contributed to the development of crop science and to the management of crop production and natural resources in South Africa (SA) over the past 25 years could give new perspectives on the benefits derived from modelling, the appropriateness of approaches employed and the best way forward. The initial objectives of the major SA modelling initiatives (ACRU, BEWAB, CANEGRO, CERES, PUTU, SAPWAT, SWB) dictated the approaches that were followed and determined their impacts. Significant advances were made with regard to improved understanding of crop growth and water use and adapting models for local conditions such as dryland grain crop production under very low rainfall. Modelling provided invaluable support for strategic investigations into the impacts of climate change, land use and water use. Many of the models succeeded in providing much-needed information to improve tactical and operational management of irrigated and dryland agriculture. Some models have been (and are being) used operationally to forecast crop production (maize, wheat and sugar) and to monitor droughts in natural vegetation, adding value to the respective industries. Modelling has formed, in some cases, an integral part of tertiary education in crop science and hydrology. This should be strengthened to build more capacity to address the ever-increasing complexity of challenges in agriculture. The review identified factors that are crucial for modelling to maintain effective impacts on the science and practice of crop production and natural resource use. These were excellent scientific leadership, long term funding, effective collaboration between local and with international groups, expertise on local agronomy and high quality experimental data for model testing and adaptation. Future modelling efforts should explore opportunities to integrate information obtained from technologies such as remote sensing and genomics.
  • Authors:
    • Singh, V. K.
    • Sah, A. K.
    • Prakash, O.
    • Singh, R. K.
    • Singh, S. N.
  • Source: Outlook on Agriculture
  • Volume: 39
  • Issue: 3
  • Year: 2010
  • Summary: Rice-wheat is the most commonly employed cropping system on around 14 million hectares of land extending across the Indo-Gangetic Plain (IGP). The IGP region covers the South Asian countries of Pakistan (2.2 million ha), India (10.5 million ha), Nepal (0.5 million ha) and Bangladesh (0.8 million ha). The major challenge facing the IGP's rice-wheat cropping system is to sustain long- term productivity. This system has a pivotal role in the food security and livelihoods of millions of farmers and workers of populous countries such as India, particularly in central Uttar Pradesh. The system's productivity and economic gains have been consistently decreasing, mainly because of the delayed sowing of wheat after the rice harvest and the fatigued soil condition. The region's farmers lose valuable time for pre-sowing irrigation and field preparation due to the gap of two to three weeks between the harvesting of rice and the planting of wheat. If wheat sowing is delayed beyond the optimal time (by late November), yields plummet at the rate of 30 kg per ha per day. The adoption of resource conservation technologies, such as zero tilled wheat sowing, is considered essential to maintain the productivity of the rice-wheat cropping system. Economic analysis of data for two years from six on- farm demonstrations shows that the zero tillage method of wheat cultivation is the most economical and attractive option for the farming community of central Uttar Pradesh. A high grain yield and reduced cost of cultivation per hectare, reduction in the density of weeds, especially Phalaris minor, and greater water saving were noted in zero tilled wheat sowings compared with conventional practices. As a result of field demonstrations and farmer training programmes, the introduction of zero till drill wheat sowing has expanded rapidly and has made significant contributions to the tillage revolution in the study area.
  • Authors:
    • Millen, J.
    • Evans, D.
    • Sadler, E.
    • Camp, C.
    • Stone, K.
  • Source: Applied Engineering in Agriculture
  • Volume: 26
  • Issue: 3
  • Year: 2010
  • Summary: Availability of spatially-indexed data and crop yield maps has caused increased interest in site-specific management of crop inputs, especially water and fertilizer As commercial equipment to implement site-specific applications of water and nutrients becomes available, crop response to variable inputs and decision support systems will be required to ensure profitable crop production while conserving natural resources and protecting the environment. The objective of this research was to determine corn yield response to a range of nitrogen fertilizer and irrigation amounts on a relatively uniform southeastern Coastal Plain soil under conservation tillage. Corn was grown in a field experiment using a center pivot irrigation system that had been modified to make site-specific applications of water and fertilizer during the period 1999-2001 on a site near Florence, South Carolina. Treatments included three antecedent crop rotations (prior four years), three irrigation regimes (0, 75%, and 150% of a base rate, IBR), and four nitrogen fertilizer amounts (50%, 75%, 100%, and 125% of a base rate, NBR), and with Put. replications. As expected, corn grain yields increased with irrigation and N fertilizer Mean corn grain yields for the three-year study ranged from 6.3 to 8.9 Mg/ha for the 0% IBR avail-twin, 9.4 to 10.5 Mg/ha for the 75% IBR treatment, and 10.0 to 10.6 Mg/ha for the 150% IBR treatment. The mean corn grain yields in response to N applications ranged from 6.4 to 8.0 Mg/ha for the 50% IBR treatment, 8.6 to 9.4 Mg/ha for the 75% NBR treatment, 9.1 to 10.9 Mg/ha for the 100% NBR treatment, and 8.8 to 11.7 for the 125% NBR treatment. However, the nature of the response varied among the three years, mainly because of differences in rainfall and rainfall distribution during the growing season. Also, during the first,year there was less response to N fertilizer (7.9 to 9.1 Mg/ha) possibly because of residual soil N from antecedent soybean crop. A regression analysis indicated that the slopes of the corn yield response to increased N fertilizer application were low for both irrigated and rainfed treatments in 1999. In both 2000 and 2001, the slopes were greater for the corn yield response to increased N fertilizer In 2000, the irrigated treatments had a greater slope of the yield response for additional N fertilizer than did the minted treatments. Using an orthogonal contrast analysis, the overall yield response for the combined irrigation treatments to N fertilizer was quadratic in 1999 and 2000, and linear in 2001. These quadratic yield response's indicated that, for these conditions, a potential upper limit on production for the applied N-fertilizer and water (rainfall and irrigation) was approached. For the minted treatment, yield response to N fertilizer was linear in all three years. These results provide useful information that should be helpful in developing management strategies and decision support systems for profitable management of both water and N fertilizer on spatially-variable soils in the southeastern Coastal Plain while conserving natural resources and protecting the environment.
  • Authors:
    • Zhang, X.
    • Shi, F.
    • Li, B.
    • Xue, Y.
    • Yang, Z.
  • Source: Journal of Henan Agricultural Sciences
  • Issue: 10
  • Year: 2010
  • Summary: By using field monitoring methods, the village, the water consumption of winter wheat grown Zhangcun town of Huixian county, Henan province were determined. Water consumption can reach 216.3-345.2 mm at the yield level of 4 500-6 000 kg/ha. The water consumption percentage constitution of different growing period was 25.9%-36.9% between seeding and reviving stages, 22.0%-31.1% between reviving and heading stages, and 31.9%-52.2% between heading and maturation. The variation was great among different years. When the yield level of corn was 6 750-7 500 kg/ha, water consumption 299.6-462 mm which account for 81.3%-97.4% of precipitation during the period of the year. The water consumption percentage constitution of different growing period was 17.1%-17.3% between seeding and jointing stages, 34.5%-39.1% between jointing and trumpet stages, and 43.6%-48.4% between trumpet and maturation stages. For both wheat and corn, the water consumption density increased dramatically after jointing stage. The jointing and seed filling stages were two important periods for wheat water consumption. The trumpet stage was important for corn. In the dry-land hilly areas of middle and north Henan province at the current situation, natural precipitation can generally meet the water demand of autumn grain crops, while for summer grain crops, it is inadequate. So the emphases of water-saving irrigation should be on the summer grain crops.
  • Authors:
    • Sharaiha, R.
    • Adamu, M.
  • Source: World Journal of Agricultural Sciences
  • Volume: 6
  • Issue: 6
  • Year: 2010
  • Summary: Mixed cropping of barley and durum wheat has been the practice of smallholder farmers in some drylands of Ethiopia even though the reasons for this successful cropping system were not well understood. Therefore, four planting densities, five intercrop proportions and three irrigation water levels were studied in a split-split plot arrangement in RCBD with three replications to determine the competition levels and resource use of barley and wheat mixed cropping under different growth stages. Barley was more competitive at early stages, while wheat dominated towards the reproductive stage. Intra- and inter-specific competition was decreased with increasing irrigation water levels but it was increased with increasing planting densities. Intraspecific competition was increased with increasing barley ratio in the cropping systems at all irrigation water levels, planting densities and harvesting stages. Fast growing nature of barley at early growth stages helps the intercropping system in that barley can capture belowground and areal resources faster, while wheat grows slowly and demands less resource at earlier growth stages. At later stages when wheat becomes dominant and resource demanding, early maturity of barley leaves more space for wheat to satisfy its resource demand. Thus niche differentiation index was consistently more than one in all growth stages and irrigation water levels. Therefore, mixed cropping of these two crop species helps combine important characters in a cropping system so as to enhance productivity through complementary resource uses in drylands.
  • Authors:
    • Karmakar, R.
    • Das, S. K.
    • Das, I.
  • Source: SATSA Mukhaptra Annual Technical Issue
  • Volume: 14
  • Year: 2010
  • Summary: In India, rice-wheat cropping system (RWCS) has contributed and will continue to contribute largely towards food security. Well-planned steps are necessary to make it sustainable and more productive without any adverse effects on the natural resources and the environment. Past studies indicate that sustainability of RWCS in the Indo-Gangetic Plains is at risk mainly due to decline in groundwater levels, soil organic matter content and nutrient availability, increased soil salinization and pest incidence. Practices for sustainable management diversified crop rotations that enhance soil cover and fertility, and accelarated adoption of resource conserving technologies like zero-tillage, bed planting, laser leveling, surface seeding, intercropping of high value crops, furrow irrigated raised bed planting technique, etc., all of which have been briefed in the present paper.
  • Authors:
    • Muchaonyerwa, P.
    • Chiduza, C.
    • Murungu, F. S.
  • Source: African Journal of Agricultural Research
  • Volume: 5
  • Issue: 13
  • Year: 2010
  • Summary: Production of large biomass yields and weed suppression from cover crops have been major constraints affecting success and uptake of conservation agriculture technologies by smallholder irrigation farmers. A field study was undertaken to evaluate biomass accumulation and N uptake by oats ( Avena sativa), grazing vetch ( Vicia dasycarpa), faba bean ( Vicia faba), forage peas ( Pisum sativum) and Lupin ( Lupinus angustifolius) and their winter weed suppression efficacy in the 2007 and 2008 winter seasons. Cover crops were grown at two fertiliser levels: no fertiliser and fertilized. Control plots were included where no cover crop was grown. At the end of each winter season, glyphosate was applied to kill the cover crops and maize planted. Oats, grazing vetch and forage pea's cover crops produced mean dry weights of 13873, 8945.5 and 11073 kg ha -1 respectively while lupin had the lowest dry weight of 1226 kg ha -1. Oats responded to fertilisation while, there was little or no response from the other cover crops. Oats and grazing vetch also reduced weed density by 90 and 80% respectively while lupin only reduced weed density by 23% compared with the control plots. Grazing vetch fixed a mean of 112 kg N ha -1. The results suggest that legumes such as grazing vetch and forage peas may be grown to maximise biomass yields with minimal fertilizer inputs. Amount of biomass produced was a major factor in controlling winter weeds, while there was a progressive decline in the winter weed burden from the first to the second season. The low C:N ratio of grazing vetch (
  • Authors:
    • Matic, T.
    • Todorovic, M.
    • Albrizio, R.
    • Stellacci, A.
  • Source: Field Crops Research
  • Volume: 115
  • Issue: 2
  • Year: 2010
  • Summary: The understanding of the interactive effect of water and N availability, associated with the ability of crops to efficiently use these resources, is a crucial issue for stabilizing cereal production in Mediterranean areas. A 3-year side by side experiment on durum wheat and barley, under different water regimes and nitrogen levels, was carried out in a typical Mediterranean environment of Southern Italy, to identify the outstanding features of these species that contribute to enhanced grain yield and improved water and nitrogen use efficiency. Wheat and barley response was assessed under three water supply regimes ( I100, I50, I0: full irrigation, 50% of full irrigation and rainfed) coupled with two N fertilizer levels (high N: 120 kg ha -1 and low N: not fertilized). In order to evaluate barley yield response under lower N rates, 60 kg ha -1 were applied in 2006. The occurrence of abundant rainfall during the experimental period determined only mild water stress during most of the growing season, especially in 2006 and 2007. Under these conditions, nitrogen fertilization was the main factor affecting crop response, and different crop traits in response to irrigation were primarily evident on tissue N concentrations. Grain number per unit land area explained a high proportion of grain yield and it was mainly influenced by N fertilization. Water availability enhanced N absorption: the response of both crops to N fertilization, in terms of N uptaken and grain N concentration, was higher in the year characterized by greater water availability during the most sensitive stages to drought stress. Under unfertilized conditions, the two crops showed similar response in terms of number of grains per unit land area; under N fertilization, barley exhibited a higher increase in number of grains per unit land area, but wheat achieved similar yields as consequence of the higher grain weight. In years characterized by similar average productivity of wheat, barley did not show further increase in number of seeds, even doubling the rate of N supplied. By increasing irrigation water supply, the two crops showed a similar yield response, but a different N partition, as confirmed by the lower nitrogen harvest index values for barley over 2007-2008. At similar total availability of N, barley reached higher N utilization efficiency than wheat, mainly because of a lower N concentration in the grain rather than a higher efficiency in using the available N.
  • Authors:
    • Al-Naeem, M.
  • Source: American Journal of Plant Physiology
  • Volume: 5
  • Issue: 3
  • Year: 2010
  • Summary: A field study was carried out to determine the effect of irrigation scheduling on growth parameters and Water Use Efficiency (WUE) of barley and faba bean crops for optimum production during the winter seasons of 2001-02 and 2002-03. Four irrigation treatments T 1 (application of water at field capacity soil moisture), T 2, T 3 and T 4 irrigation at 15, 30 and 45% soil moisture depletion of the available water at field capacity of soil, respectively were tested on a loamy-sand soil. Plant growth parameters of both the crops were significantly affected by the different irrigation treatments. Mean barley grain yield ranged from 4.52-6.72 Mg ha -1 and the faba bean seed yield from 0.86-1.45 Mg ha -1 in different irrigation treatments. The WUE, based on total grain/seed yield ranged between 0.90-148 kg m -3 of water for barley and 0.17-0.30 kg m -3 of water for faba bean in different irrigation treatments. There was no significant difference in WUE of barley and faba bean crops between T 1 and T 2 treatments. The WUE was slightly higher in T 2 (irrigation at 15% soil moisture depletion) than T 1 (irrigation at soil moisture of field capacity level). In conclusion, appreciable grain yield of barley and faba bean seed can be achieved if irrigated at 15% soil moisture depletion. The study provided useful information for scheduling irrigation of barley and faba bean crops under arid environment for efficient water use and management.