• Authors:
    • Patil, S. G.
    • Ralevic, P.
    • Loon, G. van
  • Source: Journal of Sustainable Agriculture
  • Volume: 34
  • Issue: 8
  • Year: 2010
  • Summary: Agriculture including crop production and animal husbandry provides for the food, fodder, and fuel needs in rural regions of many countries such as India. Using the knowledge pertinent to complex mixed cropping-livestock systems at the village level, the goal of this study is to develop a rational method for crop selection, such that the capacity for production of food, fodder and biomass fuel can be examined under various cropping patterns. An agricultural survey is carried out in November 2007 for three villages located in the dryland agro-ecozone of Karnataka State, India. Various demands, including human food energy and protein requirements, and constraints, including land area, are modeled for optimal cropping pattern. A clear recommendation of the study is that a substantial shift in village-wide area planted to cereal crops, in all cases over 50%, is necessary to satisfy human and livestock demands. Additionally, there are visible and growing population pressures on the resources in the dryland, semi-arid regions of India, and these strategies will need to be supplemented by improved agronomic practices directed toward increased productivity.
  • Authors:
    • Sommer, R.
    • Ryan, J.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Division Symposium 3.2 Nutrient best management practices
  • Year: 2010
  • Summary: While globally fertilizers have had a major impact on food production for the past half-century, the general use of chemical fertilizers in the semi-arid areas of the world is a more recent development. This is particularly true of the Mediterranean region, especially in North Africa and West Asia. Traditionally, the cropping system involved growing cereals (barley and wheat) in rotation with fallow to conserve moisture; sheep and goats were an integral part of the low-input system. Drought was a constant constraint on crop yields. In the past few decades, significant developments have occurred to increase agricultural output; new high-yielding disease resistant varieties; mechanization; irrigation; pest control; and particularly the use of chemical fertilizers as a supplement to the limited animal manures available. Research at the International Center for Agricultural Research in the Dry Areas (ICARDA) in collaboration with the national agricultural systems in the mandate countries of the region has made significant strides in fertilizer research. While much has been achieved in terms of best fertilizer management practices, much remains to be done. This presentation examines the use of fertilizers under the headings of the best management practice concept; right source, right application rate, right time of application, and right place. As fertilizer use will expand in the Mediterranean region, efficiency of use will be an underlying consideration. As agricultural land is on a global level is finite, with limited possibilities to expand cultivation, the increasing population of the world has correspondingly increased the needs for food and fibre. An inevitable development has been intensification of land use, particularly in developing countries of the world, leading to poverty and increased concerns about food security (Borlaug 2007). Pressure on land has been particularly acute in the arid and semi-arid regions, which are characterized by drought and land degradation. The lands surrounding the Mediterranean have been cultivated for millennia and are the site of settled agriculture and the center of origin of some of the world's major crops, especially cereals and pulses. Much development efforts have centered on the West Asia- North Africa (WANA) area, which is characterized by a Mediterranean climate and where drought is the main production constraint (Smith and Harris 1981).
  • Authors:
    • Al-Tawaha, A.
    • Al-Ghzawi, A.
    • Al-Ajlouni, M.
  • Source: Journal of Food Agriculture & Environment
  • Volume: 8
  • Issue: 3/4 part 2
  • Year: 2010
  • Summary: Field experiments were conducted in North Part of Jordan to determine the best combination of crop rotations and fertilization levels that would improve the productivity of land and increase barley production under dryland conditions. Six-year field trials were conducted from 1996/1997 to 2001/2002 growing seasons at Ramtha Agricultural Research Station in north Jordan. Treatments effect was independent from each other and it is possible to select the best combination of treatments that give the highest yield. Rotation effect varied across growing seasons. Barley/vetch rotation showed the highest productive rotation. Additionally, barley yield was the same after vetch as after fallow. The application of 30 and 80 kg ha -1 of nitrogen and phosphorus, respectively, resulted in the highest values of fertilizer utilization efficiency.
  • Authors:
    • Eslami, S.
    • Ebranimi ,E.
    • Mahmoodi, S.
  • Source: Proceedings of 3rd Iranian Weed Science Congress, Volume 1: Weed biology and ecophysiology, Babolsar, Iran, 17-18 February 2010
  • Year: 2010
  • Summary: Ceratocarpus arenarius is one of the problematic and noxious weeds in dryland farming of wheat, barley, lentil and peas in North Khorasan. Laboratory experiments were conducted on germination and seedling emergence of ceratocarpus. Germination ability of this weed species was similar in light/dark and continuous dark conditions, therefore seeds of this weed species are non-photoblastic. Seeds germinated over 80% in the range of alternating day/night temperatures (20/10, 25/15 and 30/20C) and the maximum germinability (96%) was observed at 25/15C. Seed of this weed species retained their germination ability until high salinity levels and even at 800 mM NaCl 20% of seeds germinated. Seeds of this weed species could tolerate high level of drought stress, so that 25% of seeds germinated at osmotic potential of -1 MPa. Seedlings could emerge from a range of burial depths from 0 (without covering with filter paper) to 8 cm and maximum emergence (94%) was observed in seeds planted on the soil surface covered with 3 layers of filter paper.
  • Authors:
    • Andrew, J.
    • Gazey, C.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Symposium 4.1.2 Management and protection of receiving environments
  • Year: 2010
  • Summary: Surface application of agricultural lime to treat acidity in the soil profile delivers multiple benefits to the broadcare dryland farming systems in Western Australia. Soil pH measured in 2009 to a depth of 40-50 cm was increased by applications of lime applied in 1991 and 2000. The ameliorated soil pH profile, which meets the Wheatbelt Natural Resource Management 2025 resource targets (Avon Catchment Council 2005) (designed to remove acidity as a constraint to productive agriculture), has provided multiple benefits in terms of increased productivity, increased crop competitiveness, reduced weed burden, reduced risk of soil erosion by wind due to increased biomass cover and potentially reduced off-site effects which result from decreased water use efficiency on profiles with low pH. Current annual losses due to soil acidity for the WA wheatbelt are estimated at between $300-400 million or around 9% of the total crop. The treated soil profile in this trial returned $175/ha benefit from increased wheat yield in 2008 and $225/ha benefit from increased barley grain yield in 2009.
  • Authors:
    • Singh, K.
    • Nandita, G.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Congress Symposium 4: Greenhouse gases from soils
  • Year: 2010
  • Summary: Management strategies in agroecosystems may influence C balance in soil through variation in C input to soil and also by causing variation in C output from soil. In a two year study we evaluated the effect of application of soil inputs with varying resource quality viz: high quality (C:N 16; HQR), low quality (C:N 82; LQR) and mixed quality (HQR +LQR; MQR) inputs having equivalent amount of N, on the soil CO 2 flux, % C build-up, soil C balance and crop productivity in a tropical dryland rice-barley-summer fallow agroecosystem. Addition of LQR singly resulted in high probability of C retention capacity compared to other treatments, however lower levels of soil C build-up, and crop productivity was observed. On the other hand, although in HQR treatment the C balance approached almost unity, the C build-up and crop productivity was comparable to that of the LQR treatment. Combining the two inputs resulted in significant build-up of soil C and enhancement of crop productivity and also indicated high C sequestration capacity. It is concluded that for sequestration of C, the resource quality of the input i.e., the form of C, labile or recalcitrant, is more important than the absolute amount of C added to the soil through exogenous inputs.
  • Authors:
    • Weeks, C.
    • Robertson, M.
    • Oliver, Y.
  • Source: Agricultural Water Management
  • Volume: 98
  • Issue: 2
  • Year: 2010
  • Summary: The practice of long fallowing, by omitting a year of cropping, is gaining renewed focus in the low rainfall zone of the northern agriculture region of Western Australia. The impetus behind this practice change has been a reduced use of pasture breaks in cereal crop rotations, and the belief that a fallow can improve soil water accumulation and thus buffer the negative effects of dry seasons on crop yields. We evaluated the benefits of long fallowing (full stubble retention, no weed growth allowed) in a continuous wheat sequence via simulation modelling with APSIM at two rainfall locations and five soil types. The simulated benefits to long fallowing were attributable to soil water accumulation only, as the effects on soil nitrogen, diseases or weeds were not evaluated. The long-term (100 years) mean wheat yield benefit to fallowing was 0.36-0.43 t/ha in clay, 0.20-0.23 t/ha in sand and loam, and 0-0.03 t/ha in shallow sand and shallow loams. Over the range of seasons simulated the response varied from -0.20 to 3.87 t/ha in the clay and -0.48 to 2.0 t/ha for the other soils. The accumulation of soil water and associated yield benefits occurred in 30-40% of years on better soils and only 10-20% on poorer soils. For the loam soil, the majority of the yield increases occurred when the growing-season (May-September) rainfall following the fallow was low (30 mm), although yield increase did occur with other combinations of growing-season rainfall and soil water. Over several years of a crop sequence involving fallow and wheat, the benefits from long fallowing due to greater soil water accumulation did not offset yield lost from omitting years from crop production, although the coefficient of variation for inter-annual farm grain production was reduced, particularly on clay soils during the 1998-2007 decade of below-average rainfall. We conclude that under future drying climates in Western Australia, fallowing may have a role to play in buffering the effects of enhanced inter-annual variability in rainfall. Investigations are required on the management of fallows, and management of subsequent crops (i.e. sowing earlier and crop density) so as to maximise yield benefits to subsequent crops while maintaining groundcover to prevent soil erosion.
  • Authors:
    • Ginovart, M.
    • Josa, R.
    • Sole, A.
  • Source: International Agrophysics
  • Volume: 24
  • Issue: 2
  • Year: 2010
  • Summary: In an experiment conducted in NE Spain, cereals and legumes were rotated for seven cycles using two different tillage techniques - conventional tillage and direct drilling (no-tillage: NT). Straw was removed after harvesting in both tillage systems. With NT, more than 30% of the soil surface was still covered by residues (stubble) at sowing. The soil was Calcic Cambisol and the climate aridity index was 0.76. The climatic water balance was negative, at -187 mm y(-1) from 1950 to 1980. The aims of the study were to determine the effect of tillage system on 2-D macroporosity by micromorphology, and bulk density (excavation method) of the upper layer of the ploughed horizon. To identify differences, either parametric or nonparametric statistical tests were performed depending on sample size. Direct drilling with residue removal affected bulk density, macroporosity and mean macropore area in the top 10 cm of the profile. The same effects were observed under conventional tillage. The upper layer of the studied horizon had higher total porosity than the layer beneath with both treatments. The upper layer of the horizon showed unfavourable physical conditions with direct drilling.
  • Authors:
    • Towett, B. K.
    • Ogola, J. B. O.
    • Kinyua, M. G.
    • Gottschalk, K.
    • Kimurto, P. K.
  • Source: Agricultural Engineering International: CIGR Journal
  • Volume: 12
  • Issue: 3/4
  • Year: 2010
  • Summary: Carrying out field trial-research in dryland areas is usually expensive and costly for most national breeding programmes; hence development of simple crop simulation models for predicting crop performance in actual semi-arid and arid lands (ASALS) would reduce the number of field evaluation trials. This is especially critical in developing countries like Kenya where dry areas is approximately 83% of total land area and annual rainfall in these area is low, unreliable and highly erratic, causing frequent crop failures, food insecurity and famine. This paper used data generated from the rain shelter by measurement of evapotranspiration together with weather variables in Katumani to predict wheat yields in that site. Maximum yield of the wheat genotype considered for genotype Chozi under ideal conditions was 5 t/ha. Total above-ground biomass was obtained and grain yield was to be predicted by the model. Transpiration was estimated from the relationship between total dry matter production and normalised TE (7.8 Pa). The results presented are based on the assumption that all agronomic conditions were optimal and drought stress was the major limiting factor. Predicted grain yield obtained from the conceptual model compares very well with realised yields from actual field experiments with variances of 14%-43% depending on watering regime. This study showed that it is possible to develop simple conceptual model to predict productivity in wheat in semi-arid areas of Kenya to supplement complicated and more sophisticated models like CERES-maize and ECHAM models earlier used in Kenya. The presence of uncontrolled factors in the simulation not accounted for in the estimation and could have contributed to decrease in observed yield need to be included in the model, hence modulation of the equations by introducing these factors may be necessary to reduce variances; thus need to be quantified. To improve the accuracy of prediction and increase wheat production in these areas measures that conserve water and/or make more water available to the crop such as prevention or minimisation of run-off, and rain water harvesting for supplemental irrigation are necessary.
  • Authors:
    • Bellaloui, N.
    • Smith, J. R.
    • Mengistu, A.
    • Paris, R. L.
    • Wrather, J. A.
  • Source: Crop Science
  • Volume: 50
  • Issue: 5
  • Year: 2010
  • Summary: Phomopsis seed decay (PSD) of soybean ( Glycine max L. Merr) is primarily caused by Phomopsis longicolla. Currently, percent seed infection is used as a method for evaluating resistance to PSD. However, researchers need a common system for classifying soybean genotypes for their reaction to P. longicolla that is consistent across environments. The purpose of this research was: (i) to evaluate the reaction of a select set of soybean accessions to P. longicolla, and (ii) determine the effects of irrigation and two harvest regimes (normal and delayed) on seed infection. We propose a classification system for comparing reactions to P. longicolla among accessions based on a Phomopsis seed infection index (PSII), derived by dividing the percent seed infection of each accession by percent seed infection values of susceptible standards selected within early and late maturity groups. Percent seed infection by P. longicolla infection was greater when accessions were irrigated during the growing season and harvested at normal maturity. Some lines such as MO/PSD-0259 were rated as resistant to P. longicolla (7% seed infection) when not irrigated and harvested at maturity, but were rated as susceptible (39% seed infection) with irrigation and delayed harvest. The resistance ratings to P. longicolla using percent seed infection and PSII varied among accessions. SS93-6012, for example, had similar ratings for both (9% seed infection and 16% PSII). PI 416942 exhibited some resistance to P. longicolla based on percent seed infection (8%), but no resistance based on PSII (32%). Accessions PI 594478, Delmar, SS93-6012, SS93-6181, PI 594603A, and PI 594712 were classified by PSII as moderately resistant under irrigation and with delayed harvest. These results indicate that simple comparisons of percent seed infection among accessions without irrigation, without delayed harvest, and without a standard control of a similar maturity group might result in false conclusions about resistance to P. longicolla.