Effoct of Soilamendments on the Soikl Organic Carbon Contentand Yield of red Onion Grown in Sandy Regosol SANDYREGOSOL.

Abstract

Apot experiment was carried out at the agronomy farm Faculty of Agriculture, Eastern University, vantharumoolai, Chenkalady located in Batticaloa district to develop a nutrient management technology by integrating organic manures with chemical fertilizer on red onion in sandy regosols. Four organic sources integrated with different rates of recommended chemical fertilizer were evaluated with sole recommended chemical fertilizer. There were twelve treatments including integrated organicmanureswith chemicalfertilizersat differentrates, sole organicmanuretreatment and no fertilizer as control. The treatments were arranged in a Completely Randomized Design with 3 replicates. Analysis for soil organic carbon content was carried out at planting, just before top dressing and at the time of harvest. Red onion yield was recorded at harvest. Tank silt had the greatest influence on soil organic carbon content. In tank silt and poultry manures treated soils organic carbon content was increased from initial stage to harvesting stage. There was no significant influence of partially burned paddy husk on soil organic carbon content. But it was higher at harvest. The results indicated that the integrated use of organic manure with recommendedlevel of chemical fertilizers increased the yield of red onion remarkably. Among organic manures tank silt with recommended level of fertilizers showed better response in relation to yield than others.