Effect of organic sources with and without chemical fertilizing on productivity of rice (Oryza sativa) and wheat (Triticum aestivum) sequence and plant nutrients balance in a reclaimed sodic soil

Abstract

An experiment was conducted during 2003–05 on a reclaimed sodic soil in Indo-Gangetic Plains to assess the possibility of improving productivity of rice (Oryza sativa L.) – wheat (Triticum aestivum L. emend. Fiori & Paol.) system under 2 levels of fertilizer NP application, i e 75 and 100% recommended doses of N and P for each crop with and without different organic manures, i e 10 tonnes/ha farmyard manure, 10 tonnes/ha sulphitation pressmud, in situ green manuring as Sesbania bispinosa green manure and 2.5 tonnes/ha wheat residue to rice crop only. The output:input ratio were 0.87 for N and 0.57 for P in plots of 100% NP fertilizer alone and from 0.80 to 0.93 for N and from 0.69 to 0.90 for P in plots of 100% NP with different organic manures. Total yield in the system, 10.58, 10.73, 11.14 and 10.45 tonnes/ha in receiving plots 100% NP+farmyard manure or sulphitation pressmud or organic manures and wheat residue, respectively, as compared to the yield of 9 tonnes/ha with 100% NP application without organic manure. In plots (100% NP green manure) with the maximum yield, total removal of NPK was 568 kg/ha (251 kg N, 54 kg P and 262 kg K/ha). While in 100% NP-treated plots, NPK removal was 459 kg/ha (207 kg, N, 38 kg P and 214 kg K/ha). The actural soil N balance was much lower than the expected balance indicating large losses of N from the soil. The net balance of P and K was also negative.