Maximum yield of oil palm, Peninsular Malaysia : yield response and efficiency of nutrient recovery

This paper reports on the maximum yield observed from oil palm fertilizer trials conducted between 1970 and 1980 in various locations in Peninsular Malaysia. The main objective of this paper is to highlight the observed maximum yield achieved from the 1960's planting materials and their estimated efficiency of nutrient recovery in bunch yield. One possible means of assessing fertilizer efficiency is to determine the percentage of nutrient recovery in the harvested crop. In this approach it can be assumed that the nutrients not accounted for are either immobilised in the soil or permanent parts of the palm or are lost from the system. The estimated nutrient recovery from the optimum fertilizer input to achieve maximum yield is calculated as described by Tinker (1989) and is based on estimates of nutrients in the bunch derived from Ng and Thamboo yield response at maximum yield achieved. Limiting factors which explain variation from maximum yield have been described by Foster (1989). It was observed that fresh fruit bunch yields obtained in the control plots of alluvial soils are much higher than that from sedentary soils. As expected, the response towards maximum yield in the sedentary soils is relatively much higher than that of alluvial soils. Consequently, the amount of fertilizer required to achieve maximum yield and its efficiency of nutrient recovery is higher for sedentary soils than alluvial soils. It is assumed that there is a corresponding effect on the nutrient uptake and yield response to achieve maximum yield. Thus, at optimum rates of fertilizer applied, the analysis of variance and partial correlation between yield response and control yield, soil type (alluvial and sedentary soil) and the efficiencies of nutrient recovery could provide some clue as to the nutrient which accounts for most yield response variation from achieving maximum yield. In this respect it was found that efficiency of phosphate recovery significantly contributed to the variation, at least within similar environments of Peninsular Malaysia. For highly intensive agriculture, such as oil palm, it is most relevant to focus on fertilizer efficiency at the point of maximum yield