Influence of N,P, K and Mg on Yield of Oil Palm grown on Kohong soil Series

Abstract

A study on the relationship between N,P, K and Mg as fertilizers with yield was conducted in oil palm (6-10 year old) planted under Kohong soil series at Surat Thani Horticulture Research Centre. The palms were transplanted in 1985. The design of the experiment was RCB with 5 replications and 10 treatments which tested each 4 levels of ammonium sulfate (N), triple superphosphate (P) and potassium chloride (K) fertilizer application and 3 levels of kiesertie (Mg). The investigation revealed that yield was increased 66% compared with no fertilizer plot. Moreover, fertilizer at the rate of 3-1-3 and 1.5-1-3-0.5 kg/plam/year of ammonium sulfate, triple superphosphate and potassium chloride gave the highest yield (2.80 and 2.72 tons/rai/year), respectively among all treatments.
The investigation also found a significant relationship between leaf N and K nutrient concentrations and yield of oil palm. The coeffcients of determination values (R2) were 0.7627 and 0.7253 for N and K, respectively. In addition, from the calculation the optimum concentrations of N and K in leaf were 2.66 and 0.975%, respectively. These values will be recommended for oil palm growing in sandy loam soils under east coast of southern enviromental conditions.