STUDIES ON SOIL FERTILITY STATUS IN RELATION TO PATTERN OF APPLICATION OF FARMYARD MANURE AND CHEMICAL FERTILIZERS IN IRRIGATED MULBERRY GARDENS OF KOLAR DISTRICT, KARNATAKA

摘要

Soil samples of forty-five irrigated mulberry gardens from three villages viz., Hosapet, Beechagondanahalli and Chowdadenahalli in Kolar district of Karnataka were collected from three levels (surface, 0-6 cm; middle, 0-30 cm and lower, 30-60 cm depth). The samples were analyzed following standard soil testing methods for major soil properties. The soil analysis revealed a moderate level of soil fertility with respect to majority of the plant nutrients (nitrogen and phosphorus) except potassium and zinc. More than 62 % of the soil samples revealed organic carbon above 0.5 %. Significant variations were observed in soil pH and the electrical conductivity at different depths. However, the soil micro-organisms (bacteria and actinomycetes) were found tobe present in usual range (normal) and fungi in high range in all the samples tested. The crop-wise application of farmyard manure and chemical fertilizers in different forms (complex, urea, ammonium sulphate, single super phosphate and muriate of potash) also influenced the fertility status of the soil. Significant correlation was observed between the soil micro flora (bacteria and actinomycetes) and the available zinc content while fungal population was negatively correlated with nitrogen input The pH was negatively correlated with the available zinc while electrieal conductivity was positively correlated with organic carbon. High degree of variations in several parameters in soil samples indicated the degree of heterogeneity in the three villages of similar ecosystem. The result clearly suggests that there is a need for an integrated plant nutrient supply system comprising of various organic manures, inorganic fertilizers and biofertilizers besides factors associated with nutrient use efficiency such as soil type, crop geometry, methods and time of application of inputs, quantity and better source of fertilizers to maintain optimum soil fertility.