Optimisation of Soil Test Based Potassium Fertiliser for Low Land Rice in Udic Haplustalf through Recycling of Rice Straw

摘要

A Field experiment was conducted to study the effect of graded levels of soil test based K with the application of rice straw (RS),silicate solubilizing Bacteria (SSB),RS+SSB and sodium meta silicate (SMS) on grain yield of rice in Udic Haplustalf.The application of RS+SSB ranked best by registering the highest grain yield of 5218 kg per ha followed by RS (4957 kg ha~(-1)),SMS (4790 kg ha~(-1)),SSB (4720 kg ha~(-1)) and the control recorded the lowest grain yield of 4419 kg per ha.The yield data was subjected to linear and quadratic model for optimisation of soil test based (STB) K under the influence of RS,SSB,RS+SSB and SMS.The good fit was found only with quadratic as evidenced in the response of grain yield to the applied STB K was increasing with decreasing level.Further,the rate of response to the added K was varied as indicated in the slope of the curve.The magnitude of response was greater in control followed by SMS,SSB and RS.The lowest response to the added STB K was observed in the plot treated with RS+SSB as it registered lowest physical and economic optima of 43.6 and 17.2% STB K,respectively.