Long term effect of integrated nutrient management on soil properties and availability of nutrients in a Typic Hapludalfs under maize-wheat cropping
Abstract
To study the long term effect of integrated nutrient management on soil properties and available nutrients, surface and subsurface soil samples were drawn from the long-term field experiment (LTFE) which is in progress on a Typic Hapludalfs at Research Farm of College of Agriculture, CSK HPKV, Palampur, Himachal Pradesh, India since Rabi, 1972. The rotation followed was maize-wheat and the treatments included various combinations of N, P, K, Zn, lime, hand weeding and farm yard manure. Results from the study showed that integrated nutrient management over the years resulted in improvement in the soil properties as well as status of available nutrients in the soil at both the depths. Continuous application of urea as a source of N has resulted in acidification of soils (pH 4.3) while lime application increased the pH to 6.2 in the surface soil and 6.0 in subsurface soil. The treatment 100 % NPK + FYM resulted in 66 per cent increase in soil organic carbon content over initial value. Similar effects were recorded on cation exchange capacity and available nutrients. It can be concluded from the study that integrated nutrient management is essential to maintain soil health.
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Introduction
Fertilizers play vital role in productivity of any crop but continuous and imbalanced use of high analysis chemical fertilizers badly influences soil health and ultimately production potential of soil. With the advent of modern agriculture, farmers are either using restricted amount of organics or no organics. As a result of such nutrient management practices, many of the productive soils are becoming unproductive. This has led to decreasing yield trend even with optimum use of fertilizers particularly under the situations where high yielding varieties are being used. The problem is more severe in acid soils which are under intensive cropping. To secure India’s food and nutritional demands, maintenance of soil health is indispensable. Chemical fertilizers alone are unable to maintain the long-term soil health and crop productivity (Subba Rao & Srivastava 1998) as they lack in secondary and micronutrients. Continuous cropping and long-term fertilization are liable to change soil properties and crop productivity. Long-term fertilizer experiments provide the best possible base to monitor changes in soil quality and crop productivity due to continuous manuring and cropping and hence to evolve future strategies for maintaining soil health and enhancing crop yields. With this background, the long term effect of fertilizers and amendments on soil properties and available nutrients was evaluated in the present study.
Conclusion
Significant improvement in the soil properties and availability of nutrients was observed by the addition of FYM in combination with chemical fertilizers in surface as well as subsurface layers. Application of lime periodically during 37 years increased the pH of soil from its initial value thereby neutralizing the soil acidity. There is a significant increase in soil organic carbon with the continuous application of FYM to maize crop for 37 years. The integrated use of optimal dose of NPK and FYM is helpful in maintaining soil health. Continuous use of recommended levels of N alone through urea (without FYM) has deleterious effect on soil quality. Imbalanced fertilization has proved to be a great threat to the sustainability of our farming systems. Amelioration of soil acidity in Acid Soil Regions (ASR) besides using recommended application rates of N, P and K is a beneficial proposition under situations where availability of organics (FYM) is limited.
