Productivity, quality and nutrient balance in spring sugarcane (Saccharum spp. hybrid complex) under organic and inorganic nutrition

An experiment was conducted during spring season of 2008-09 and 2009-10 on sandy loam soil at Pusa to as-sess the effect of farmyard manure and fertilizer levels on sugarcane (Saccharum spp. hybrid complex). The ex-periment was laid out in factorial randomized block design and replicated thrice with two FYM viz., 0 and 20 tonnes/ha and four fertilizer levels viz., F1' 150 + 37.1 + 49.8, RDF; F2' 150 + 43.6 + 66.4; Fa' 200 + 43.6 + 83.0 and F4' 200 + 54.6 + 99.6 ~g N + P + K/ha. Application of 20 tonnes FYM/ha to sugarcane recorded significantly higher mean growth (tillers, 1, 70,200/ha; cane height, 208.9 cm; drymatter accumulation, 33.3 t/ha), yield at¬tributes (millable canes, 1,13, 600/ha; cane diameter, 2.18 em) and cane yield (87.5 t/ha) over no FYM. An in¬crease of 16.2; in cane yield, 26.31; in net return, 8.5; in benefit: cost ratio and 15.6; in sugar yield was no¬ticed with FYM over its control. FYM @ 20 tonnes/ha registered an increase of 20.9; in N uptake, 20.3; in P up¬take, 20.2; in K uptake, 10.0; in available N, 23.3; in available P and 6.4; in available K ove.r no FYM. Net gain of N (65 kg), P (6.1 kg) and K (31 kg) were also highest in FYM added plots. Crop receiving 200 + 54.6 + 99.6 kg N + P + K/ha gave significantly higher tillers (1,83,800/ha), cane height (213.8 cm), drymatter (34.5 t/ha), cane diameter (2.22 cm) and number of millable cane (1,20,800/ha) though, it was statistically at par with 200 + 43.6 + 83.0 kg N + P + K/ha. There was an increase in cane and sugar yield with each successive increase in N + P + K level from 150 + 37.1 + 49.8 kg/ha to 200 + 43.6 + 83.0 kg/ha. Increasing N + P + K levels from F, to Fa signifi¬cantly increased the net returns. However, further increase to F4 level did not proved profitable option. Fertilizer application increased the N uptake from 164 to 238 kg/ha, P uptake from 14.9 to 21.9 kg/ha and K uptake from 191.3 to 277.6 kg/ha. Significant increase in available N status was recorded with an application of 200 + 43.6 + 83.0 kg N + P + K/ha. However, available P status in post harvest soil increased significantly with each successive increase in fertilizer up to highest levels i.e. 200 + 54.6 + 99.6 kg N + P + K/ha. Available K status was the highest (121 kg K/ha) at 200 + 54.6 + 99.6 kg N + P + K/ha though it was on par with 200 + 43.6 + 83.0 kg N + P + K/ha. Net gain of N, P and K were progressively increased with increase in N + P + K levels from 150 + 37.1 + 49.8 to 200 + 54.6 + 99.6 kg/ha.