Effect of planting geometry and fertilizer N rates on nitrate leaching, nitrogen use efficiency, and sugarcane yield
Keywords:Nitrate leaching, Nitrogen use efficiency, Nitrogen rates, Planting geometry, Sugarcane, Yield response
AbstractIn a field experiment conducted over two consecutive cropping seasons (1989-91 and 1990-92) at Lucknow, India, autumn sugarcane (Saccharum officinarum L. cv. Colk 8001) was fertilized with 0, 75, 150, 225, and 300 kg N ha-1 and planted at (i) 40 000 three-bud setts per hectare in single rows spaced at 90 cm apart (conventional planting); (ii) 80 000 three-bud setts per hectare in single rows spaced at 90 cm apart; and (iii) 80 000 three-bud setts per hectare in paired (double) rows having 30- and 60-cm spacings within and between paired (double) rows, respectively. The double-row planting technique, on an average, minimized the nitrate-N leaching from inter-row spaces, thus increasing recovery of applied N by 15.8% over conventional planting. Consequently, the yield response per kilogram applied N was 369 kg cane from double-row planting compared with 278 kg cane from conventional planting. With increasing losses of nitrate-N due to leaching, recovery of applied N decreased from 72.3 to 30.9%, respectively, when the rates of applied N increased from 75 to 300 kg ha-1.The yield response also decreased from 443 to 224 kg cane for each kilogram of N applied between these rates.