Response of spring-planted sugarcane (Saccharum officinarum) to phosphorus and sulphur application

An experiment was conducted during the spring season of 2003–04 and 2004–05 on sandy loam soil at Pusa, Bihar to study the effect of four levels each of phosphorus (0, 17.5, 35.0 and 52.5 kg/ha) and sulphur (0, 40, 80 and 120 kg/ha) on growth and yield of sugarcane (Saccharum officinarum L.). Application of 35.0 kg P/ha to sugarcane recorded significantly higher mean growth (tillers, 175,000/ha; cane length, 221.0 cm; leaf area index, 4.04), yield attributes (millable canes, 131,100/ha; single-cane weight, 570 g; cane diameter, 2.02 cm) and cane yield (73.54 t/ha) over no P. The mean increase in cane yield with application of 52.5, 35.0 and 17.5 kg P/ha over the control was 20.77, 18.83 and 9.97% respectively. Application of 35.0 kg P/ha registered an increase of 4.4% in sucrose content in juice, 31.8% in P uptake and 22.1% in S uptake over the control. The use efficiency of P decreased with corresponding increase in its level. However, S-use efficiency was maximum at higher level of P application. Apparent P recovery was the highest at 35.0 kg P/ha (8.07 and 8.68%), whereas apparent S recovery progressively increased with increase in P levels from 0 to 52.5 kg/ha. The response of sulphur was also pronounced at 80 kg/ha as evident from significant increase in mean cane length (219 cm), leaf area index (4.02), number of millable canes (131,000/ha), single cane weight (566.0 g), cane yield (73.17 t/ha) and sucrose content in juice (17.3%). Sulphur levels significantly improved the uptake of P and S up to 80 kg S/ha and the increase was 21.4 and 22.2% over the control respectively. Application of 120 kg S/ha recorded maximum P-use efficiency (361.6 kg cane/kg S applied) and apparent P recovery (8.75%), but it recorded S-use efficiency (121.6 kg cane/kg S applied) up to 80 kg/ha level only. There was decrease in apparent S recovery with successive increase in S level from 40 to 120 kg S/ha.