Some pulverisation techniques of clearing old palms for replanting

The ban on open burning of old oil palm biomass at replanting has resulted in very high breeding of the rhinoceros beetle (Oryctes rhinoceros) in the palm biomass. The rhinoceros beetle has emerged as the most serious pest in immature and young mature palms in Malaysia currently. This paper reports 2 no-burn methods of clearing old oil palms, whereby almost the entire palms were pulverized and spread widely over the field and the root mass dug up at felling. The first method consisted of felling, chipping and spreading of palm chips by an excavator, followed by 2 rounds of pulverization by a tractor drawn mulcher 40 to 60 days later, with one round of ploughing in between to dig up the missed and buried palm chips. The ploughing also helped to spread the pulverized palm biomass more evenly and improved the field condition for the planting of leguminous cover crops and palms. An alternative technique whereby a tractor-drawn mulcher was replaced by an excavator-driven mulcher was also evaluated. The second method involved pulverizing the standing and newly felled palms in a one-off operation with 3 types of machines called the EnviroMulcher, MountainGoat and Beaver. The results of the rhinoceros beetle population census in fields cleared by the first method indicated that it was effective in reducing the breeding of beetles. This was reinforced by the low levels of pest damage on the replanted palms in 3 plantings on 2 estates. Although beetle population and pest damage census were not carried out for the other methods, it could be inferred that they would be as effective, as all the methods have the same objective of pulverizing the entire palm and spreading the pulverized palm biomass as thinly as possible throughout the field, thus, making them unsuitable for beetle breeding. The methods of land clearing also have the potential of reducing the Ganoderma disease problem. They could confer other potential benefits, such as more efficient utilization of nutrients released by the decomposing palm biomass by the newly replanted palms and shorter fallow period. The clean clearing methods also facilitated replanting and the subsequent field upkeep work. These zero-burn techniques of replanting are environmentally less polluting and could contribute to sustainable palm oil production.