Machito MIHARA, Rangsarit SRIMUANG, Makoto ICHIMIYA / and Lalita SIRIWATTANANON （Tokyo University of Agriculture）
Organic farming with compost is expected to work as soil environment conservation. However, the density of organic matters in compost is around 2.0g/cm3, which tends to be smaller than soil particles. So, it is easy to be washed out by surface runoff and to pollute water environment. In this study, pellet compost was developed with adding soil and molasses at a certain ratio to compost, and the effects of pellet compost on plant growth and on nitrogen losses were compared with those of chemical granular fertilizer or traditional compost. The experimental results indicated that pellet compost with 0.01 molasses (0.1% in mass concentration) were sufficient for plant growth. However, there was a tendency for plant growth to be reduced when adding more than 0.1 molasses(1%) into pellet compost. Also the experimental results using slope model plots under an artificial rainfall simulator showed that the nitrogen losses from the plots applied pellet compost with 0.01 and 0.05 molasses (0.1 and 0.5%) were remarkably lower than those applied chemical fertilizer or traditional compost. In addition, organic matter contents in sediments from the plots applied pellet compost with 0.01 and 0.05 molasses were lower than that applied traditional compost. It was concluded that pellet compost with 0.01 molasses was effective to reduce the losses of nitrogen and organic matters by surface runoff.
pellet compost, nitrogen, surface runoff, plant growth, slope model