Does Soil Compaction Affect Oil Palm Standing Biomass?

Soil compaction could be either desirable or detrimental to plant growth, depending on the severity of compaction. The compaction treatments applied in this study on a coastal alluvial soil, Bernam series (Typic Endoaquepts) had resulted in significant reduction of oil palm total standing biomass in compacted plots. The oil palm total above-ground standing biomass comprising of fronds and trunk in the control plots was significantly higher than the compacted plots by 12%. Even though there was no significance difference in trunk heights, the palms were taller in 4T plots (tractor with 4 t trailer weight). Palms in compacted plots exhibited a significantly smaller trunk diameter, lower trunk dry weight and reduction in the frond dry weight by about 9%, 8% and 6%, respectively. The total green frond number, total leaf area and leaf area index (LAI) were not significantly different (p less than or equal to 0.05) between the treatments. Total green frond number per palm was 33 to 35 fronds per palm. The LAI averaged more than 5 for all treatments implying compaction did not hinder photosynthesis process. Hence, the changes in soil physical properties such as bulk density, porosity, available water and hydraulic properties were considered not limiting to palm growth as they adapted well to the compaction treatments. (author)