Response of gobhi sarson (Brassica napus subsp oleifera var. annua) plus toria (B-campestris var. toria) to fertilizer and manure and their residual effect on maize (Zea mays)

A field study conducted with gobhi sarson (Brassica napus L. ssp. oleifera DC. var. annual) + toria [B. campestris var. toria Duth. & Full)-maize (Zea mays L.) sequence during winter (rabi) season 1992-93 and rainy (kharif) s eason 1994 showed that the dry-matter accumulation and photosynthetically a ctive radiation (PAR) interception by the intercropped gobhi sarson and tor ia and their seed yields were increased with increased supply of N, P or fa rmyard manure (FYM). in farmyard-manured plots (5 tonnes/ha, dry-weight bas is), 144 ky N/ha and 65 kg P2O5/ha were computed as economic optimum dose o f nutrients, at which, 1,713 kg and 1,582 kg seed yield (total of gobhi sar son and toria) of the system was predicted respectively. In unmanured plots , yields were lower and 120 kg N/ha was found economic optimum dose, wherea s response to P was linear up to the highest level (80 kg P2O5/ha). Applica tion of FYM increased the apparent recovery of applied N by 57.4% and of P by 117.0%. Available N contents at the end of the 2 years, did not register any change, while the available P was up by 5.2 kg P/ha and available K by 5.4 kg/ha. Residual effects of graded levels of N, P and FYM on succeeding maize were not significant, making application of appropriate fertilizers to maize imp erative in gobhi sarson and toria-maize (Zea mays L.) cropping system.