5. CONCLUSIONS
The study concludes that the distribution of particle size of the soils studied did not vary significantly because they were formed from the same parent material (basement complex rocks). Nutrient mining in plantations is possible as continuous cultivation has been observed to minimize major and minor plant nutrients. Heaping palm fronds were found to yield some advantages over time in terms of carbon content, but could not provide enough nutrients to substitute what the crop used. The rate of decomposition of organic materials increased with high temperatures, and the release of nutrients was faster than plants could quickly absorb and use, and was often subject to losses associated with erosive precipitation. As pruned fronds and cut plants continue to boost the structure of the soils to a point that soil bulk density values are relatively low, the impact of organic matter addition to soils was seen to be beneficial. The study recommends that the accumulation of organic residue on the floor of plantations should be championed as it will help sustain increasing levels of organic matter. It is important to promote more research on how to efficiently use pruned fronds for compost to be spread around the oil palm trees.