Y. S. Ramakrishna

Strategies for Improving the Productivity of Rainfed Farms in India with Special Emphasis on Soil Quality Improvement

Rainfed agriculture encounters several constraints on account of climatic, edaphic, and social factors. Out of the 97 million farm holdings, about 76% come under marginal and small categories. The productivity levels of these areas have remained lower across years because of frequent droughts occurring due to high variability in the quantum and distribution of rainfall, poor soil health, low fertilizer use, imbalanced fertilization, small farm size and poor mechanization, poor socio-economic conditions and low risk-bearing capacity, low credit availability and infrastructure constraints. Consequently, farmers are distracted from agriculture and tend to migrate to cities to look for alternative jobs. Hence, there is a great need to increase the productivity of rainfed crops and overall net returns to keep the farmers in agriculture. A paradigm shift in rainfed agriculture can be expected through technological thrusts and policy changes. The strategies that need to be emphasized include: (i) land care and soil-quality improvement through conservation agricultural practices, balanced fertilization, harnessing the potential of biofertilizers and microorganisms, and carbon sequestration; (ii) efficient crops, cropping systems, and best plant types; (iii) management of land and water on watershed basis; (iv) adoption of a farming-systems approach by diversifying enterprises with high-income modules; (v) mechanization for timely agricultural operations and precision agricultural approach; (vi) post-harvest, cold-storage, value-addition modules; (vii) assured employment and wage system; (viii) organic farming; (ix) rehabilitation of rainfed wastelands; (x) policy changes and other support system; and (xi) human-resource development, training and consultancy. This paper deals in depth with some of these issues and strategies.

Kinetics of Decomposition of Un‐conventional Farm‐Based Crop Residues and Their Composting and Quality Monitoring

Abstract Castor and sunflower, drought‐tolerant crops, are cultivated in the semi‐arid tropics of the world. The nutrient‐rich residues of these crops are mostly burnt because of their high C/N (C/N)‐ratios. These high C/N‐ratio residues can be composted and recycled successfully, if they are supplemented with other low C/N‐ratio farm‐based organics and some chemical additives. To study the rate kinetics and half‐life of decomposition of castor (C/N ratio: 75∶90) and sunflower (C/N ratio 57∶47) residue mixtures and the manure value of the compost thus prepared, two on‐farm experiments were conducted at Hayathnagar Research Farm (17° 18′ N latitude, 78° 36′ E longitude, and an elevation of 515 m above sea level) of Central Research Institute for Dryland Agriculture, Hyderabad, India. The decay rate constants obtained on the basis of the exponential functions using the data on weight loss, C concentration, and C/N ratios indicated that among the four combinations of treatments, castor stalks+gliricidia loppings+cattle dung had the fastest rate of decomposition with an average rate constant value of 0.0043 day−1. To achieve 50% decomposition (half‐life), the time periods computed for castor stalks+gliricidia loppings+cattle dung and sunflower stalks+gliricidia loppings+cattle were 197 and 278 days, respectively. On an average basis, sunflower‐based manure contained a significantly higher amount of total N (14.6 gm kg−1) than castor‐based manures (12.2 gm kg−1). The corresponding total hydrolyzable N values were 8.2 and 8.15 gm kg−1, respectively. Amino acid N was found to be the predominant constituent of the total acid hydrolyzable N in the manure. Use of earthworms in composting enriched the manure in terms of mineral [nitrate (NO3)+ammonium (NH4)‐N] and hexosamine‐N fractions. The full article deals with the decomposition patterns (periodical changes in weight loss, C concentration and C/N ratios), decay‐prediction functions, composting, and manure quality of the castor‐ and sunflower‐based residue mixtures.