THE INFLUENCE OF ROUTINE AGRICULTURAL ACTIVITIES ON THE QUALITY OF WATER IN A TROPICAL RICE FIELD ECOSYSTEM

Physico-chemical parameters of the rice field water of Bukit Merah Agricultural Experimental Station (BMAES), Penang, Malaysia were investigated during two cultivation seasons of 2004/2005. The selected variables showed wide ranges of variation. Except for total organic matter (TOM) and total suspended solid (TSS), the values of all variables were significantly different at all sampling occasions. Most of the physico-chemical parameters showed significant relationship to the water level either in the presence of rice plant or after harvesting of the crop. The rice agroecosystem is a complex ecosystem due to the interaction of aquatic organisms, including algae and macrophytes. This unique swampy ecosystem is usually disrupted during ploughing, drainage, harvesting and application of fertilizers and pesticides. It was concluded that the agricultural activities in this rice field contributed effectively in creating the wide variations in the values of physico-chemical parameters.