[Preliminary results on comparison of ground magnesium limestone and kieserite on oil palm yield]

An experiment was carried out to compare the performance of Ground Magnesium Limestone (GML) and kieserite on oil palm planted on Rengam series soil (Typic kandiudult) in the Kerteh region, the northeastern part of Peninsular Malaysia. The experiment commenced in March 1989 on a 1981 DxP planting. The rates tested were 0, 0.12, 0.24, 0.36 and 0.48 kg Mg0/palm/year. An additional treatment of 0.48 kg Mg0/palm/3 years for GML was included to evaluate the practicality of less frequent application of this fertilizer. Each rate was equally split and applied twice a year together with other basal fertilizers. The experimental design was a RCBD with three replicates. The plot size was 5x5 palms with the central nine as recording palms. Preliminary results over a 5 year period (1990-1994) showed that there was no significant difference between GML and kieserite in promoting the fresh fruit bunch (FFB) yield, although kieserite has a slight edge over GML. The best kieserite treatment was 0.36 kg Mg0/palm/year whereas the best GML treatment was 0.48 kg Mg0/palm/year, the highest rate tested. At their respective best rates, kieserite resulted in higher yield although not statistically significant. Application of GML at 0.48 kg Mg0 every three years did not improve FFB yield as compared with the control treatment. There were no significant differences in both bunch number and bunch weight arising from the two fertilizers. Leaf Mg was improved by the application of the two fertilizers, as compared with the control plot without Mg fertilizer. However, there were no significant differences in leaf Mg between the GML and kieserite treatments although the former tended to give slightly higher leaf Mg level. Applications of both GML and kieserite tended to suppress leaf K, with stronger effect from GML application. With GML application, leaf Ca was improved but leaf P was suppressed, both substantially. Both GML and kieserite had no significant effect on the leaf N level. Based on the current results, it appears that kieserite has a slight edge over GML in promoting oil palm yield. However, more data from this experiment are needed to ascertain the perfomance of these fertilizers on oil palm.