[pp.39-44]

Efficiency of Granular Compost in Reducing Soil and Nutrient Losses under Various Rainfall Intensities

Lalita SIRIWATTANANON and Machito MIHARA （Tokyo University of Agriculture）

Abstract:
Soil and nutrient losses from agricultural fields cause various environmental problems. Especially, over enrichment of nitrogen and phosphorus in water systems is causing severe eutrophication in Southeast Asia. In Thailand, organic fertilizer is currently apt to be focused, as it contributes to reduce the expense of chemical fertilizer and may harmonize with natural environment. However, rainfall or surface runoff may wash out compost easier than soil particles, as the density of compost is lower than soil particles. So, the objective of this study is to evaluate granular compost comparing with chemical fertilizer or conventional compost from a viewpoint of reducing soil and nutrient losses under various rainfall intensities at 15, 30, 45 and 60 mm/hr. The results showed that soil and nitrogen losses from the plot applied conventional compost were smaller than those applied other fertilizers at lower intensity than 30 mm/hr. When rainfall intensity was higher than 45 mm/hr, the losses from the plot applied granular compost were the lowest among plots. Also, organic matter losses from the plot applied granular compost were significantly smaller than those applied conventional compost at higher rainfall intensities. So, it was concluded that granular compost is the effective way for decreasing the amounts of soil and nutrient losses from agricultural fields, which may contribute to sustainable agriculture.

Key Word:
granular compost, soil loss, nutrient loss, organic matter loss, rainfall intensity

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