PENENTUAN DOSIS OPTIMUM PEMUPUKAN N, P, DAN K PADA SORGUM (SORGHUM BICOLOR [L.] MOENCH)
ABSTRACT: Development of
sorghum processing industries is essential in expanding sorghum market as wells
as it’s an economic value. Fertilizer is needed in planting. Nitrogen,
phosphorus, and potassium availabilities are the most limiting factors for
maximum growth and yield. Sorghum (Numbu Variety) was planted to evaluate the
maximum and optimum rates of N, P, and K fertilizers. The research was
conducted in Cikarawang field, Darmaga, Bogor from MarchJuly 2015
with multi-nutrient response method. Each experiment evaluated different
rates of N, P, and K fertilizer with randomized complete block design and three
replications. The fertilizer rates were 0, 50, 100, 150, and 200% of
recommendation rate (100% N = 120 kg N ha-1, 100% P = 36 kg P2O5 ha-1, and 100%
K = 90 kg K2O ha-1). The result showed relative yields of sorghum increased
quadratically based on y = -0,0015x2 + 0,4011x + 67,571 for N, y = -0,0012x2 +
0,2917x + 78,457 for P2O5, and y = -0,001x2 + 0,2777x + 74,457 for K2O. The
maximum rate for each nutrient was 160,4-43,7-124,9 kg N-P2O5-K2O ha-1.
Fertilizer recommendation based on P threshold (no P) was 36,7-0,0-13,7 kg
N-P2O5-K2O ha-1, K threshold (no K) was 22,0-0,0-0,0 kg N-P2O5-K2O ha-1, and no
fertilizer needed on N threshold. The optimum rate fertilizer based on the
yield vs. cost rule, therefore, the most economical recommendation would be
160,4-43,7-124,9 kg N-P2O5-K2O ha-1.
Penulis: Ratna Suminar, Suwarto,
Heni Purnamawati
Kode Jurnal: jppertaniandd170469
