Oil Palm Bulletin No. 39 (November 1999) p32-44

Towards a higher yield potential, production and its prediction in oil palm

CHAN Kook Weng

As the oil palm industry stands poised to enter the 21stcentury, it is an appropriate time to take stock of the lessons learned in the first 100 years of the crop in Malaysia. The end of the century is not just time to look at Y2K compliance for the new century, but, more importantly, to assess the three Ps – (yield) potential, production and prediction – in order to allow the oil palm industry to progress further. In the assessment, however, it must be borne in mind that what is good in the past may not necessarily be so for the future.

During the past century, significant improvements in the actual and potential yield have been made through breeding by crossing outstanding individuals. More recently, biotechnology has been invoked. While breeding in oil palm is largely focused on the development of pest and disease resistance, the new tool of biotechnology has the scope for not only increasing yield but also to modify the product (oil) quality. Raising the yield potential must be accompanied by an effort to achieve it and good oil quality to boost by using a proven management plan in a systems approach. Many management factors impinge on yield and oil quality like, for example, variety, planting density, earliness, soil fertility, site, fruiting patterns, pest and disease control, maintenance and harvesting, milling and storage. Perhaps the most important of all is plant variety. Each of the factors must be examined holistically so that it can be addressed independently. It is important to remember that each of them can, individually and severally, affect the yield and quality of oil and, therefore, the crop value and profitability.
In the new millennium, planting oil palm solely for its oil may not hold anymore as fibre from its biomass becomes important for composites. Research on oil palm should therefore focus on its total productivity as both the oil and biomass would be economic products. Its ‘productivity’ will then be the total dry matter produced and what is important will be the energy harnessed to produce this. Oil palm productivity depends on three factors – the incident solar energy, the fraction of solar energy intercepted by the crop canopy and the efficiency of conversion of the intercepted radiation into dry matter. If the two economic products have different values, then the dry matter partitioning into them will also be important. Each of the four factors (three + partitioning) are examined for a better understanding of their roles in contributing to yield.
Currently, palm oil and palm kernel oil are the economic products of oilpalm. Their combined production expressed as a ratio to the total dry matter production gives the harvest index while the ratio of bunch dry weight to total dry matter production is the bunch index. As assimilate is first required for vegetative growth, only the surplus is given to bunch production. The quantum of ‘overflow’ for bunch production is dependent on both the environment and bunch load in the endogenous palm cycle. The vegetative dry matter production can vary with soil fertility, pollination, etc., and the yield thereby affected. A further consideration is the energy content in the dry matter as the oil contains much more energy than non-oily matter. Oil represents only 4O% of the dry matter in the bunch but over 60% of its energy. An understanding of the physiological processes in partitioning is therefore necessary to predict the yield.
To predict yield, an understanding of floral sex differentiation is required. This paper gives the major correlations found between yield and rainfall at various times earlier corresponding to the different physiological processes then occurring. As oil palm yield is sensitive to water stress, the rainfall in these broad lag periods are used in long term yield prediction of up to two years. For shorter periods of 6 to 12 months, the Ulu Bernam and ARIMA methods are used.
Finally, in line with the likely future adoption of precision agriculture, physiological knowledge on the crop must be supplemented by satellite reconnaissance to predict yield over larger areas, e.g. a whole estate, region or even the country. From satellite images, a means should be found to discern the physiological stresses suffered by the crop and the yield potential of the site arrived at. The estimates of crop yield and, if possible, the peaks and troughs as well, should be correlated with ground observation so that satellite reconnaissance can be used to predict the national yield. Deriving such a yield forecasting system, together with the actual production knowledge already available, will pave the way towards a knowledge-based oil palm industry.

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