Responses of irrigated oil palm to nitrogen, phosphorus and potassium fertilizers on clayey soil

Nutrient demand for oil palm is determined by the potential yield, which is varies according to genotype, soil, palm age and environmental factors. Moisture stress having a strong influence on oil palm growth and development. Therefore, a study was conducted to determine the effect of nitrogen (N), phosphorus (P) and potassium (K) fertilizers on growth performance and yield response of oil palm in irrigation system. This study using 3(3) NPK factorial fertilizer design were conducted on mature D x P palms planted on Gong Chenak soil series (Aquic kandiudults) at Felda Agricultural Services Sdn. Bhd. (FASSB), Tembangau 9 estate (03 degrees 00 ' 59.5 '' N Longitude 102 degrees 28 ' 48.5 '' E) in the year 2000 under irrigation condition. The fertilizer rates for respective fertilizers (kg nutrient/palm/year) were N (0, 0.84, and 1.68 kg N), P (0, 0.68, and 1.36 kg P2O5) and K (0, 0.24, and 4.8 kg K2O). A normal field operation and maintenance for the oil palm was used throughout 7-year (2005-2012) study period. Mature oil palms treated with complete NPK fertilizer (N1P1K1 and N2P2K2) increased 17.3% in an average fresh fruit bunch yield (FFB) from 22.9 ton/ha/year in control plot to 27.0 ton/ha. The results of this study highlighted the positive response of palm growth and foliar nutrient status with N manuring throughout this study period. Fertilizer rate at 0.84 N, 0.68 P2O5, and 2.4 kg K2O was the best rate to maintain optimum palm growth, particularly on estimated leaf area index (LAI) and frond dry weight, FFB yield response and foliar nutrient status.