Impact of intensive highland agriculture on the ecosystem

B. Y. Aminuddin, W. Y. Wan Abdullah, U. B. Cheah, M. H. Ghulam, M. Zulkefli and R. B. Salama

Abstract

The highlands in Malaysia are fragile ecosystems due to steep slopes, sandy soils and high rainfall. Condition in the highlands is ideal for planting sub-tropical crops. Vegetables and flowers are cultivated intensively on terraces and platforms, resulting in land degradation. This project examined the soil and nutrient losses for three different cropping systems in the Cameron Highlands i.e. cabbage and tea in open areas, and flowers in rainshelter. High erosion rate (82 t/ha/yr) and high water pollution due to the applied fertilizers and pesticides were observed in open vegetable plots, making cultivation unsustainable. In contrast, similar indicators suggest that tea cultivation and floriculture under rainshelter are far more sustainable; the erosion rate under rainshelter is only about 1 t/ha/yr. Nevertheless rainshelters must be constructed in conformity to the landscape and the excess intercepted runoff water must be properly managed to avoid landslide risk and riverbank erosion. The fertilizer application under rainshelter must also be properly managed to avoid excessive soil salinization. The level of organic water pollution at the farm level is high. Nevertheless it is much reduced in the subcatchment and it is even lesser in the catchment waters, due to the dilution effect. Among all pesticides, only endosulfan persists beyond permissible limit in the catchment.

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