Quantity-intensity parameters of potassium and their relationship with potassium fractions, soil properties and wheat (Triticum aestivum L.) yield under integrated nutrient management system in a typic ustifluvents

Abstract

Fertilizer use in India is highly unbalanced especially with respect to potassium (K) and the soil shows significant responses to K application, even in alluvial soils dominated by K bearing minerals. Potassium availability to the plant is influenced by internal soil properties and other external properties. Quantity intensity characteristics are one of the satisfactory measures of potassium dynamics and its availability. So quantity intensity characteristics of potassium were studied to quantify the potassium availability in soil classified as typic ustifluvents. Soil samples (0-15 cm) were collected from the experimental plot located at Mandan Bharti Agriculture College, Agwanpur, Saharsa, Bihar after harvest of wheat during rabi 2015-16. The experiment was laid out in split plot design with four levels of NPK viz., 0, 50, 100 and 150 per cent recommended NPK in main plot and four levels of organic sources of nutrients viz., no organic manure, vermicompost, water hyacinth compost and vermicompost + water hyacinth compost in sub plot treatment in three replications. Soil K pool quantity intensity relationship, K release kinetics along with grain yield and K uptake of wheat were studied. Equilibrium K activity ratio was positively correlated with available, water soluble, exchangeable, non-exchangeable and total K. Non-significant and negative relationship of PBCK with all forms of K were obtained. ΔG showed non-significant but positive correlation with water soluble, exchangeable, available and total K. The Q/I parameters were significantly interrelated with each other. Equilibrium activity ratio was positively significantly correlated with grain yield, straw yield, K uptake and organic carbon. The sand, silt and clay showed significant relation either positive or negative with all quantity-intensity parameters. The result suggested that integrated use of organics and K input regularly sustain a steady supply of K to successive crops.