Optimization of nitrogen use for wheat (Triticum aestivum) grown in sequence with rainy-season crops

A field experiment was conducted during 1992-93 and 1993-94 to study the ef fect of preceding rainy-season (kharif) crops on nitrogen requirement of wh eat (Triticum aestivum L, emend. Fiori & Paol.), The optimum dose of N for wheat was lowest (91.6 kg/ha) when it was grown after green-manure crop dha incha [Sesbania cannabina (Retz.) Pers.], with corresponding economic yield of 46.9 q/ha. When wheat was grown after blackgram (Phaseolus mungo L.) th e optimum dose of N was found to be 121.0 kg/ha, with wheat yield of 43,6 q /ha which was the second lowest after dhaincha-wheat sequence. Response of wheat to N was also found maximum in dhaincha-wheat sequence (26.82 q/ha) a nd lowest in rice-wheat and fodder sorghum [Sorghum bicolor (L.) Monech]-wh eat sequence.