To Study the Effect of Fertilizer and Organic Manure on Dynamic Changes of Potassium Under Cropping Sequence.

ABSTRACT

A field experiment was conducted in a farmer’s field in the Red and Laterite zone of West Bengal to evaluate the effect of integrated use of FYM and concentrated organic manures and chemical fertiliser on dynamics of potassium in soil in relation to growth and yield of component crops viz., Potato, Sesame and Rice. Three levels of chemical fertilisers viz., (i) 75% of the RDF, (ii) 100% of the RDF, and (iii) 150% of the RDF and three levels of organic manures (i) Control- applying no 0rganic manure; (ii) FYM at 20 ton/ha, and (iii) a consortium of concentrated organic manure were applied in potato after which sesame and rice were grown with the residual nutrients. Under all the three crops, application of higher doses of chemical fertilizer resulted in greater decrease in soil pH and increase in soil EC, soil OC, exchangeable, water soluble and non-exchangeable K contents of the soil. Among the two organic manures applied, the values of these parameters of the soil under all the three component crops were the highest under application of FYM. The highest pooled mean value of soil pH and lowest EC, OC, exchangeable, water soluble and non-exchangeable K contents of the soil, irrespective of the component crop in the cropping sequence, was observed under RDF75 without any organic manure and the highest under RDF150 with application of FYM. Pearson correlation co-efficient among different soil and plant parameters suggested strong relationship among themselves and K content of rice shoots, and straw of the component crops. Under limited availability of FYM, commercially available sea weed extract based concentrated organic manures could be handy and effective.