Yield responses to phosphate fertilizer in oil palm
1992
Zin, Z. Zakaria | Foster, H.L. | Tarmizi Mohammed, A. | Mohd Tayeb Dolmat (Palm Oil Research Inst. of Malaysia, Serdang, Selangor Darul Ehsan (Malaysia))
The yield response to rock phosphate fertilizers was studied in oil palm. Data from 10 field trials conducted on different soil types in Peninsular Malaysia at two different time periods were analysed. Results indicate that for inland soils, yield response to oil palm replants to application of CIRP is generally profitable up to at least 3-4kg per palm per year. However for the coastal soils the rate is up to 2-3kg P fertilizer per palm per year. It was also noted that there was no indication of any reduction in P requirements with time on these soils. For both soil types, full P response depends on adequate N fertilization. Conversely no response to N fertilizer is obtained if P is inadequate. It was also observed that on inland soils, the optimum leaf P level was approximately 0.165 percent regardless of age. If P level is found to be lower, an increase in P fertilizer rate is recommended. A very strong response to P fertilizer can be expected if soil extractable P in the weeded circle is below 15 ppm. However on coastal soils, neither leaf nor soil P level has been found to be of any use in indicating P fertilizer requirement
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