Role of soil organic carbon on root-knot disease of cotton and uptake of a few biochemical constituents

Growth of cotton plants increased significantly with corresponding increase in organic'carbon from 0.58% (10 g FYM/kg soil) to 1.27% (30 g FYM/kg soil) which was at par with 1.63 (40 g FYM/kg soil) However, nematode galling and reproduction decreased with increasing level of organic carbon. The disease intensity was maximum in unmanured check. Both under nematode inoculated and non-inoculated conditions, uptake of N, P, K total sugar and total phenol was higher in FYM supplemented plant compared to unamended soils. However, non-inoculated plants recorded higher uptake and contents. Further, irrespective of nematisation, uptake of these constituents was highest at 1.27 and 1.63% organic carbon while lowest in soils having 0.27% (check) and 0.58% organic carbon.