Dynamics of soil health in a rice berseem system as influenced by organic nutrient management

Abstract

newline The need for sustainable, eco-friendly and safe agriculture has given boost to the concept of organic farming. Organic farming employs various nutrient sources in which manures play an important role. These manure may also have varying impact on soil as well as crops to which they are applied. A study was carried out to evaluate the impact of different organic manures, such as FYM, vermicompost (VC), poultry manure (PM), and neem cake (NC) on soil characteristics and productivity of rice-berseem system on a sandy clay loam. There were no significant difference among the various treatments with respect to pH, EC and water holding capacity. Fluctuations in pH and EC were observed before and after rice harvest, with values being higher after berseem harvest. Soil available N, K, Zn and Fe were significantly increased by manure application. However available P was significantly higher over control only where PM was applied in combination with FYM and VC. Bulk density (BD), porosity and infiltration rate (IR) were improved by application of manures, although no significant differences among manures were observed. Application of manures decreased BD and increased IR. Dehydrogenase, alkaline phosphatase, microbial biomass carbon and available nitrogen increased upon application of manures. These soil biological properties increased after harvest of berseem in comparison to the values obtained after harvest of rice, indicating beneficial impact of having a legume in the rotation. As expected, all soil carbon pools (permanganate oxidizable carbon, organic carbon and total organic carbon) increase after application of manures with the exception of particulate organic carbon. As high as 0.68% of organic carbon was observed on FYM + PM application in comparison to a low of 0.49% in control, where no manure was applied. Very labile C, less labile C and non-labile carbon were significantly affected by manure treatments over control. Interesting results were obtained with respect to carbon management index (CMI).