Changes in soil fertility status as influenced by continuous cropping and fertilizer application

Summary Changes in soil fertility status brought about by the application of P and K fertilizers and farmyard manure (FYM) to a fixed wheat-maize rotation for 10 years in a calcic ustochrept are reported. The treatments comprised three rates of P (0, 30 and 60 kg P2O5/ha), two rates of K (0 and 30 kg K2O/ha) and two rates of FYM (0 and 15 t/ha) applied to maize or wheat alone or to both the crops. Organic carbon and available P and K contents of the soil increased significantly with the addition of FYM. P application at 60 kg P2O5/ha nearly maintained the original level of available P even after 10 years of continuous cropping. However, a considerable and highly significant increase in available P was obtained with the combined application of P and FYM. Available K status of the soil remained more or less unaffected by K application. Organic carbon content, and available P and K contents were significantly higher in the plots that received fertilizers and manure for both the crops than in those where the application was to maize or wheat alone.