Phosphorous solubilization from rock phosphate in presence of vermicomposts in Aqualfs

Rock phosphate (RP) alone or in combination with vermicomposts was incubated at room temperature in Aqualfs to reveal their effect on nutrient dynamics. Different types of organic wastes viz. cow dung, grasses, aquatic weeds and municipal solid wastes (MSW) were used for vermicompost preparation. Fresh cow dung is the cheapest and most commonly used bulk organic manure in India. So it was also applied as a treatment for comparative study between vermicompost and cow dung. Higher rate of P-mineralization was recorded in soil treated with RP as compared to other treatments. But after 60 days of incubation, available P content was declined in this soil, and finally it (14.36 mg kg(-1)) became statistically at par with available P-content of soils received vermicompost prepared from grass (13.66 mg kg(-1)) and cow dung (13.43 mg kg(-1)). Application of vermicompost in soil increased pH, organic carbon, mineralizable nitrogen and exchangeable potassium content in soil as compared to the application of RP alone. Clustering was done to identify the similar treatments using standard technique. We also proposed a bi-phasic model, which could explain the dynamics of phosphorus release in acid lateritic soils. (C) 2009 Elsevier B.V. All rights reserved.