Performance of Early Maturing Sugarcane (Saccharum spp Hybrid complex) Varieties under Different Row Spacing and Fertilizer Levels in Plant Cane-Ratoon-Wheat System

A field experiment was conducted at SBI, RC, Karnal, to assess performance of newly developed six mid early maturing sugarcane cultivars i.e. Co 0116, Co 0118, Co 0237, Co 0238, Co 0239 and Co J 64 (Standard), with two row spacing (75 and 90 cm) under three fertility levels i.e.75, 100 and 125% of recommended dose of fertilizers (RDF) NPK (N150 P21.8 K41.5) with plant-ratoon-wheat system. Varieties ‘Co 0238' and ‘Co 0118' recorded the maximum and significantly higher cane yield (93.1 and 88.9 t/ha) and commercial cane sugar (11.76 and 12.49 t/ha) and outperformed rest cultivars in plant and ratoon crop, respectively. However, both cultivars did not differ significantly for cane yield and commercial cane sugar (CCS). Growth attributes like cane length and cane girth of plant crop were not affected at closer spacing of 75 cm, but number of millable canes (NMC), cane yield and sugar yield increased by 23.94, 20.29 and 19.63% than 90 cm row spacing. While in the subsequent ratoon crop number of millable canes (NMC), cane yield and CCS yield increased substantially by 19.25, 16.70 and 16.92 per cent respectively at 75 cm than 90 cm row spacing. Closer spacing (75 cm) fetched maximum net return ( 209280 and 118823) with benefit: cost ratio of 1.42 and 2.27 with plant as well as ratoon crop respectively. Fertility level of 125 % RDF, being at par with 100% RDF registered improvement in yield attributes and produced increased cane yield and CSS both from plant as well as ratoon crop over 75 % RDF. Except varieties, the quality parameters did not undergo significant variation due to change in row spacing and fertility treatments. In monetary terms also, 100 % RDF found almost equally remunerative with 125 % RDF. Cultivar × fertility level interactions indicated that varieties ‘Co 0238' and ‘Co 0239' were equally productive at normal fertility level of 100% RDF. After ratoon harvest, wheat was grown in the Sugarcane-ratoon-wheat (S-R-W system) show that, 100 and 125 % of RDF levels in previous plant cane and ratoon crop gave higher wheat yield t o the magnitude of 197 and 449 kg ha-1 than 75% of RDF. Except fertility levels in plant and ratoon crop, the yield parameters and yield of wheat did not undergo significant variation due to change in row spacing and sugarcane varieties. In terms of sugarcane equivalent yield of sugarcane-ratoon-wheat system, closer row spacing (75 cm) with recommended dose of fertilizer in early maturing varieties of sugarcane namely Co 0238, Co 0239 and Co 0118 gave significantly higher yield (≥ 200 t/ha) than other varieties. In monetary terms, sowing of Co 0238 of sugarcane variety fetched maximum net returns ( 285633) followed by Co 0239 ( 253406) and Co 0118( 247453) in two years cropping system of Sugarcane-Ratoon-Wheat system under the sub tropical conditions.