For the nearly 70% of India’s population of 1.2 billion who reside in rural villages, agriculture is often the primary source of income, as well as of food, fodder and fuel. Rural agricultural systems are recognized as complex mixed-cropping-livestock systems, whereby primary and secondary products from one component of the system are used in another. For instance, primary products such as grain and milk from livestock can be used for human consumption, while secondary products such as crop residues can be used as fodder or fuel, while manure finds use as fertilizer. Variations in cropping pattern and intensity will determine the production potential of food, fodder and fuel within a region. As limiting factors, land area and yield must also be considered in agricultural planning activities. The present research aims to develop a rational method for crop selection within a particular agro-ecoregion. An optimization model is constructed to optimize for selected parameters that are set to maintain defined basic minimum standards for human nutritional and livestock fodder demands. An agricultural survey was carried out in 2007 for three villages in Karnataka State, India. All three villages were located within the dryland agro-ecozone, where crop yields are relatively low. The survey was stratified according to household landholding area ranging from marginal (0-1 ha) to large (>4 ha). Information was solicited on the demographic indicators of the population, the cropping cycle and cropping varieties used within the regions, and certain livestock parameters were gathered. Various demands, such as human food energy and protein requirements as well as fodder, and constraints, such as land area, were modeled to determine the potential for food, fodder and fuel production under optimal cropping pattern. The linear programming software, What’sBest, Version 9.0 from LINDO systems, was used to solve the optimization model. Results indicate that the current export-driven cropping pattern produces inadequate food to satisfy human nutritional demands at the village level, particularly among marginal and small households, who produce in the range of only 10 and 50 % of required food energy and protein, respectively, on a household basis. The current cropping pattern is also inadequate to satisfy village-wide livestock fodder demand, especially in villages heavily centered on cash crops,wherein only 30-40 % of fodder demand can be accounted for. On an individual household level, it is determined that a minimum 0.8 ha of land area is required to satisfy both food and fodder demands, placing strain on marginal households, who own less then 1 ha of land. The optimization model also demonstrates that it is possible to produce adequate food and fodder for both human and livestock consumption within the land area available in all the villages, if between 30-60% of land area is cultivated with food-based crops used for village wide consumption. This would require diversion of between 50 and 90 % of current land area under oilseeds and commercial crops to cereal based crops. In villages that cultivate sufficient proportion of cereal and pulse based food crops, as little as 4 % diversion of crops towards cereals may be necessary. Results also indicate that double cropping systems can generate crop residues sufficient to provide fuel for generation of 2.6-11.3 kWh/hh/day of electricity, adequate for cooking and lighting; this could be done at the same time as providing enough primary product to satisfy food and fodder needs. / Thesis (Master, Environmental Studies) -- Queen's University, 2008-06-24 16:12:50.1

No description available.

Agricultural management practices including tillage and irrigation have a considerable effect on soil physical and hydraulic properties in space and time. Tillage practices initially alter the soil physical and hydraulic properties depending on the type and depth of tillage. These changes are reverted back to original conditions due to reconsolidation during cycles of wetting and drying. Irrigation techniques can manipulate the reversion process dynamically due to different modes of wetting. The combined effects of tillage and irrigation have rarely been investigated. Therefore, two experiments were conducted to investigate the effect of different tillage practices and irrigation techniques on soil physical properties and temporal variations in soil hydraulic properties, one on wheat and second on the following maize crop grown on the same plots. The tillage and irrigation treatments implemented for the wheat crop were repeated for the subsequent maize crop restoring the same treatment layout plan. Intact soil core samples were collected, in the middle of the wheat crop before irrigation and the end of the maize crop season, for the determination of soil physical and hydraulic properties. Field saturated hydraulic conductivity (K_fs) was determined using the Guelph pressure infiltrometer method and volumetric soil water content (θ_v) and potential (ψ_m) was measured in the field using water content sensors and tensiometers, respectively. The wheat crop received rain showers from time to time, while in maize, a heavy spell of monsoon rains following tillage caused most of the soil reconsolidation. So, the greater intensity of rains, rather than the cycles of wetting and drying, became primarily responsible for the differences in soil physical and hydraulic properties between the two crops. Moldboard plow resulted in an increase in yield and improvement of soil hydraulic properties during both crop seasons. Flood irrigation reverted back the effects of tillage on soil hydraulic properties greater than sprinkler irrigation, while it did not affect the yield significantly. The dynamics of volumetric soil water content (θ_v) differed, depending on tillage type, irrigation technique and crop season. Moldboard plow was the wettest after rain or irrigation events but it dried quicker than other tillage treatments. Flood irrigation caused higher wetting than sprinkler irrigation. These wetting effects were greater in wheat as compared to maize crop. Temporal variability calculated as time averaged relative difference in θ_v was greater during wheat as compared to maize, while temporal stability calculated as standard deviation of temporal stability decreased with flood irrigation in both crops. Soil bulk density (ρ_b) and water retention characteristics (θ_v (ψ_m )) measured on the intact soil cores and total porosity (φ), plant available water capacity (θ_PAWC) and pore size distribution calculated from water retention data depended on the time of sampling. During wheat, the ρ_b was lower resulting in a higher φ than after maize. Moldboard plow decreased ρ_b increasing φ, while the effect of flood irrigation was opposite in both crops with greater magnitude in wheat. Similarly, the effects of tillage on θ_v (ψ_m ) were observed in both crops, while those of irrigation were observed in maize only. Cultivator treatment retained higher θ_v at higher ψ_m (−30 and −100 kPa), followed by chisel and moldboard plow. Plant available water capacity (θ_PAWC) was greater in maize as compared to the wheat crop. Cultivator had higher θ_PAWC than chisel and moldboard plow in both crops. Wheat had greater volume of larger pores (> 10 μm, φ_(>10)), whereas extraordinary rains as well as irrigations after tillage caused these larger pores to decrease in maize. Moldboard plow had higher φ_(>10) at 10 cm depth in both crops with greater magnitude in wheat. Field saturated hydraulic conductivity (K_fs) determined before irrigations and at the end of both crop seasons was greater in wheat than in maize especially in the first determination. Moldboard plow exhibited greater K_fs followed by chisel plow and cultivator in both crops and it decreased significantly with time in wheat but not in maize. Flood irrigation was responsible for a reduction in K_fs and the effect was greater in wheat as compared to maize. It was concluded that a greater intensity of water application in the form of rains or irrigations can revert the changes in soil physical and hydraulic properties induced by tillage more effectively than the cycles of wetting and drying. Soil hydraulic properties may be optimized with the combination of suitable tillage and irrigation for efficient utilization of water resources.