Study on feasibility of drip irrigation in shallow ground water zones of eastern India
Although the effectiveness and economics of drip irrigation systems are well established in areas having undulating topography and water scarcity, its economics in plain areas bestowed with good quality ground water at shallow depths are not yet studied. Due to this, there is confusion among farmers as well as planners regarding the guidelines for selection and propagation of this system in such areas. This study attempts to evolve guidelines for deciding the economic threshold value of fixed cost of drip irrigation system for sugarcane crop. Nomographs have been developed to find the threshold value of economic fixed cost of drip irrigation system (exclusive of pumping unit) for a combination of variables, depth of water table, yield level under check basin irrigation, expected yield gain with adoption of drip system, irrigation requirement with check basin, and electricity charges. The perusal of nomographs shows that the factors influencing the economics of drip irrigation in order of importance are yield gain ratio, electricity charges, irrigation requirement and depth of ground water.
Concept of Water, Land and Energy Productivity in Agriculture and Pathways for Improvement
Land and water are finite natural resources, which are diminishing due to indiscriminate and unscrupulous exploitation. Ever increasing population is also posing a challenge to produce more from the available resources. Proper understanding of the concept of land, water and energy productivity has become quite relevant in recent days. The technologies/ strategies in which input application is more precise, efficient and cost effective and output is adequate in quantity, excellent in quantity, well in time and profitable, will lead to enhancement of land, water and energy productivity in agriculture. In this paper, concept of land, water and energy productivity, assessment procedure of crop and agricultural water productivity and case study of Pabnawa minor in Kurukshetra, Haryana (India), have been discussed and various means/ pathways to enhance productivity by employing suitable technologies/strategies have been highlighted.
Investigations on the rôle of organic matter in plant nutrition
1. As the result of decomposition of green manure in a swamp soil, the coarse fractions (including coarse and fine sand) of the surface layer (first 3 inches) decreased by 11·2 per cent. while the fine ones (silt+clay) increased by 9·8 per cent. in the course of 43 days. The effect was less pronounced in the manured soil maintained at 60 per cent. saturation, while no alteration was to be noticed in the case of the unmanured specimens. 2. Treatment with dilute hydrochloric acid prior to dispersion had no appreciable effect on the estimates of mechanical composition obtained in the different cases. Loss in solution was also comparatively small. 3. The silica-sesquioxide ratio increased slightly as the result of decomposition of green manure in swamp soil. The composition of the fine fractions was also altered, the total percentages of the oxides of iron, aluminium and silicon increasing from 90·5 to 99·3 in the course of 71 days. 4. The practical significance of the above and related observations has been discussed.