Forms of soil potassium under different soils of paddy growing areas of Nagpur district and their relationship with yield of paddy

Abstract

The present investigation was carried out during 2018-19 in paddy growing areas of Nagpur district of Maharashtra to ascertain the effect of potassium on yield of paddy. This was carried out by conducting survey of paddy growing farmers field of Nagpur district and therefore, total 25 fields were selected on the basis of GPS and two samples were collected from each field (50 samples) after harvest of paddy. Sampling was done at surface (0-15 cm) and sub-surface (15-30 cm) depth having common management practices. The result revealed that, the available, water-soluble, exchangeable, non-exchangeable, lattice and total K in surface soil depth ranged from 144.86-224.55, 5.1-8.1, 139.76-217.25, 673.13-789.50, 5316.40-7324.64 and 6250-8322 mg kg-1,respectively and in subsurface soil, it ranged from 126.64-214.19, 3.9-7.7, 120.84-207.29, 628.12-778.00, 6013.73-7241.60 and 6900-8140 mg kg-1, respectively. A highly significant and positive relationships were observed between different forms of K and yield of paddy. The yield of paddy showed significant and positive coefficient of correlation with available K (r=0.707**), exchangeable K (r=0.697**), water-soluble K (r=0.553**) at 1 % level of significance and with total K (r=0.388*) at 5% level of significance. Further it is observed that, amongst potassium fractions, available K and exchangeable K were strongly positively correlated (r=0.999**) irrespective of soil depth. Also, it had exhibited significant and positive correlation with non-exchangeable K in both surface and sub-surface layer in paddy growing soils. The exchangeable K showed positive and significant correlation with non-exchangeable K (r=0.393*) and (r=0.395*) and lattice K also showed positive and highly significant correlation with total K (r=0.996**) and (r=0.992**) in surface and sub-surface depths, respectively.