Effect of different salinity levels of a soil on nutrient availability of manure amended soil

Abstract

Sri Lanka has been identified as one of the tropical country where scattered dry zone is now under Agricultural benefits. In order to that, salinization is recognized as the major factor contributes in land degradation, which ultimately influence on crop yield.Saline soil which is characterized with salt comprises the high concentration of soluble salts and very low amount of organic matter as well as nitrogen content.Release of inorganic forms of nutrients in soil is functionally associated with carbon mineralization hence, is affected by the salinity stress that inhibits the mineralization of organic materials in soil. For that, present study was designed to assess the plant nutrient availability of manure treated soil at different soil salinity levels. A laboratory study was conducted to evaluate the effect of different soil salinitylevels on nutrient availability. Cow dung and paddy straw were chosen as organic amendments and applied at the rate of 10 tons/ ha. Manure decomposition and nutrient availability studied at three salinity levels namely 1500 ppm, 2000 ppm and 2500 ppm. The study was arranged in a completely randomized design (CRD) using 7 treatments and replicated three times .Treatments were incubated at 25oC for 42 days.With increasing salt concentration nutrient availability was significantly decreased in manure amended soil. Application of cow dung to soil had shown highest available N (0.223%) and P content (110.14ppm) at 1500ppm salt concentration. Highest available K content