A conceptual framework for determining economically optimal fertiliser use in oil palm plantations with factorial fertiliser trials
- 212 Downloads
The theory, and the statistics and mathematics of using factorial fertiliser trials to assist in making fertiliser recommendations for neighbouring commercial plantings is presented as a conceptual framework and in a format for practical application. As an example, the yield and leaf nutrient levels from a typical factorial fertiliser rate trial (nitrogen by potassium) were modelled using multiple linear regression and the resulting response surfaces used to determine the maximum agronomic yield and optimum economic yield and to calculate the requirement for ‘basal’ fertiliser. Leaf nutrient data in both the trial and commercial plantings was used to estimate the requirement for ‘corrective’ fertiliser, where necessary, to increase the leaf nutrient levels to the target leaf nutrient level for maximum yield. All the mathematics required can be incorporated into a spreadsheet calculator that uses costs (e.g. fertiliser) and prices (e.g. oil) to calculate optimum economic fertiliser application rates. Problems with extrapolating the results of fertiliser trials to commercial plantings can be overcome by matching each trial with a corresponding commercial planting domain.
KeywordsFertiliser response Regression models Economic optimum Oil palm Fertiliser nitrogen Fertiliser potassium Application rate
This research was conducted while the author was employed by Papua New Guinea Oil Palm Research Association. The author wishes to thank Dr Hugh Foster for an introduction to the use of multiple linear regression as a method of analysing factorial trials; and Thomas Fairhurst for critically reviewing and improving the manuscript before submission. The author also wishes to thank staff of the Papua New Guinea Oil Palm Research Association and Milne Bay Estates for conducting and maintaining Trial 504.
- Campbell LC (1998) Managing soil fertility decline. In: Rengel Z (ed) Nutrient use in crop production. Hawthorn Press Inc., New York, pp 29–52Google Scholar
- Corley RHV, Tinker PB (2003) The oil palm, 4th edn. Blackwell Science, OxfordGoogle Scholar
- Foster HL (2003) Assessment of oil palm fertiliser requirements. In: Fairhurst T, Härdter R (eds) Oil palm: management for large and sustainable yields. Potash & Phosphate Institute/Potash & Phosphate Institute of Canada/International Potash Institute, Singapore, pp 231–257Google Scholar
- Hartley CWS (1988) The oil palm, 3rd edn. Longman, LondonGoogle Scholar
- Kraip J, Webb MJ (2005) Monitoring of oil palm (Elaeis guineensis Jacq.) leaf nutrient variations to help interpret routine leaf sampling results: PNG OPRA trial 136. Papua New Guinea Oil Palm Research Association, Kimbe. p 29Google Scholar
- Rankine IR, Fairhurst TH (1999) Field handbook-oil palm series, vol 3. Mature, Potash and Phosphate Institute, SingaporeGoogle Scholar
- Smith FW, Loneragan JF (1997) Interpretation of plant analysis: concepts and principles. In: Reuter DJ, Robinson JB (eds) Plant analysis: an interpretation manual. CSIRO Publishing, Collingwood, pp 3–33Google Scholar
- Verdooren R (2003) Design and analysis of fertiliser experiments. In: Fairhurst T, Härdter R (eds) Oil palm: management for large and sustainable yields. Potash & Phosphate Institute/Potash & Phosphate Institute of Canada/International Potash Institute, Singapore, pp 259–278Google Scholar
- Wilkie AS, Foster HL (1989) Oil palm response to fertilisers in Papua New Guinea. In: PORIM international palm oil development conference, Kuala Lumpur, Malaysia, 5–8 September, 1989, pp 395–405Google Scholar