Optimum Plant Nutrient Management for Oil Palm

Abstract

Oil palm (Elaeis guineensis Jacq.) is an important economic crop of Thailand, including the lower South of Thailand. At present, farmers encounter the problem of increasing production costs, due to the lack of proper knowledge and understanding of nutrient management, resulted in low yields per land field and chemical fertilizers are expensive. Therefore, this research was conducted to test plant nutrient management for oil palm production to increase yield or reduce cost during the year of 2016-2021. From the test, it was found that the two recommended methods: fertilizing according to the leaf analysis and fertilizing according to leaf analysis in combination with mycorrhizal bio-fertilizer for 30 g./tree. The results reported that the production and the economic returns from the two methods were similar, but higher than the common fertilization method used by farmers. By fertilizing according to the leaf analysis value in combination with mycorrhizal bio-fertilizer for 30 g./ tree, it resulted in an average of 4,125 kg. /rai/year of oil palm bunch, providing an average net income of 11,751 baht/rai/year. The average benefit cost ratio (BCR) was 3.34, which was not statistically different from the fertilization method according to the leaf analysis, which produced an average oil palm bunch yield of 4,107 kilograms per rai, resulting in an average net income of 11,728 baht/rai/year, with an average BCR of 3.38. In meanwhile, for the common method of fertilizing used by farmer, the average oil palm bunch was 2,812 kg/rai/year. This resulted in an average net income of 9,079 baht/rai/year with an average BCR of 4.75. By fertilizing according to both recommended methods, the yield of oil palm bunch is higher than the farmers' common fertilization for 46.69 and 46.05 percent respectively and resulting in higher net income than the farmers' common fertilization by 29.43 and 29.17 percent respectively. However, considering the soil before the experiment, the root infestation of endemic mycorrhizal bacteria was 57.15 percent. After the experiment, the average root infestation of mycorrhizal fungi was 50.00 percent for the first fertilizing method, followed by the third method - the common method of fertilizing used by farmer, at 39.17 percent, followed by the second method - the fertilizer application according to the leaf analysis and fertilizing according to leaf analysis in combination with mycorrhizal bio-fertilizer for 30 g./tree, which resulted 36.33 percent. Therefore, the increased yield of oil palm bunch from the recommended method is caused by fertilizing according to the leaf analysis, not from using mycorrhizal bio-fertilizer at the rate of 30 g./tree. In addition, fertilizing according to leaf analysis resulted in a marginal rate of return (MRR) of 105.49 percent. Hence fertilizing according to the leaf analysis is the optimum plant nutrient management for oil palm production in Songkhla Province.