Penetapan Dosis Pupuk N, P dan K pada Terubuk (Saccharum edule)

Abstract

Terubuk (Saccharum edule) was grown in Cikabayan, IPB, Bogor to optimised fertilizer rate. Treatments : N, P, K fertilizer rate of 0%, 50%, 100%, 150 % and 200% from fertilizer recomendation (100% N = 100 kg N/ha, 100% P = 135 P2O5 kg/ha, 100% K = 135 K2O kg/ha). Hundred percent of P, 40 % N, and 40 % K were aplied pre-plant, and 60% N and K were fertigated 6 times. This experiment using randomized completely block desigin with three replication. Plot size = 5 x 1,5 m, terubuk planted in double rows per plot, 70 cm between rows, and also 70 cm within rows. The result showed that vegetatif growth increas with fertilizer aplication. Total and relative yield increased quadratically. Base on y=-0.001x2+0.297x+65.05 for N, y=-0.005x2+1.105X+21.4 for P2O5 and y=-0.001x2+0.651x+4.015 for K2O. The optimum rate for each nutrient were 149-111-326 kg N-P2O5-K2O/ha same with 330-307-543 kg Urea-SP36-KCl/ha. Fertilizer recomendation base on N threshold (no N) was 0-34-83 kg N-P2O5-K2O/ha and P threshold (no P) was 0-0-26 kg N-P2O5-K2O/ha, and no fertilizer needed on K threshold. Recomendation based on optimum yield, percentages in crease in cost 60.8%, was heigher than the expected increase in yeald (28%). Acording to the yield and cost rule therefore, the most economical recomendedation would be 0-34-83 kg N-P2O5-K2O/ha same with 0-95-139 kg Urea-SP36-KCl/ha (N threshold).