Ground magnesium limestone as a source of magnesium for mature oil palm on sandy soil in Malaysia
1998
Goh, K.J. | Chew, P.S. | Teoh, K.C.
Interaction of magnesium (Mg) and potassium (K) in oil palm on sandy soil in Malaysia was examined by means of a 3 Mg x 2 K factorial experiment. Ground magnesium limestone (GML) was used to supply Mg to investigate its potential as a source of fertilizer. K was applied in the form of Muriate of potash (MOP). A standard treatment comprising kieserite and MOP was also included for comparison. Magnesium symptoms were prominent in plots without Mg treatment. Both GML and kieserite were effective in overcoming the deficiency and increased fresh fruit bunch (FFB) yield by an average 11 percent over five years. The relative agronomic efficiency of GML compared to kieserite was 83 percent indicating that the soluble sulphate form of Mg had higher supplying capacity. But the relative economic efficiency of GML was 1.5 times better than kieserite due to its lower price. The positive FFB response to GML was mainly attributed to the increased soil Mg content rather than improvements in soil pH and soil Ca content. GML also significantly enhanced leaf Mg concentration but caused an apparent drop in leaf K concentration. However, the antagonistic interaction of Mg and K on FFB yield was not found in this experiment despite the continuous applications of GML. Leaf B and Mn concentrations were generally lower with GML input. There was also a significant FFB yield response to K up to 3.0 kg K/palm/year. At this rate, soil exchangeable K accumulated to 0.40 cmol/kg which was above the generally accepted critical level of 0.20 cmol/kg. The result further showed the importance of cationic relationship in oil palm nutrition
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