Enhancing productivity and sustainability of sugarcane plant-ratoon system through planting geometry, dual-porpose legume intercropping and nitrogen nutrition

An effect of intercropped dual-purpose legumes in spring sugarcane plant-ratoon system was studied during 1997-98 to 1999-2000 at the Indian Institute of Sugarcane Research, Lucknow. The yield of sugarcane inter- cropped with cowpea [Vigna unguiculata (L.) Walp.] (67.0 tonneslha) and greengram (Phaseolus radiatus L.) (68.5 tonneslha) was comparable to that intercropped with Sesbania for green-manuring (72.2 tonneslha). Sig- nificantly highest cane-equivalent yield (80.3 tonneslha), sugar-equivalent yield (9.47 tonneslha), net monetary returns (Rs 33,341lha) and nitrogen addition (71.6 kglha) to the soil through incorporation of green biomass was recorded with sugarcane + cowpea intercropping system. Population density of 125% gave significantly higher number of millable canes (1 19,40O/ha), cane yield (73.7 tonneslha) and cane-equivalent yield (78.7 tonneslha). However, normal planting was found remunerative (Rs 36,696lha). The growth and yield parameters of sugar- cane as well as monetary returns significantly increased by application of 150 kg Nlha. Sugarcane + cowpea in- tercropping system proved highly productive and most economical. Cropping system x N level interaction indi- cated that sugarcane + cowpea as well as sugarcane + greengram were equally productive at higher level of N (1 50 kg Nlha). There was significant increase in number of millable canes, cane yield and sugar yield of ratoon from counter part plant crop intercropped with cowpea and greengram. Key words : ' I . Intercropping, Dual-purpose legumes, Nitrogen nutrition, Planting density