Effects of Shearing Force in Surface Runoff on Nutrient Losses from Chemical and Organic Fertilizers

2 Abstract: Organic fertilizer, especially compost, is apt to be focused as it contributes to reduce the expense of chemical fertilizer and may harmonize with natural environment. So, this study dealt with the nutrient losses from chemical and organic fertilizers under various simulated shearing forces from 0 to 0.25 dPa and the difference in plant growth among chemical fertilizer, conventional compost and granular compost applications. For demonstrating shearing forces caused by surface runoff, water resistance experiment was conducted employing a rotating machine. The experimental results showed the losses of total nitrogen, total phosphorus and suspended solids from granular compost of 2.5, 5, 10 and 15 mm in diameter were significantly lower than that from chemical fertilizer or conventional compost at 95% confidence interval. Furthermore, plant length and live weight of Komatsuna from the pots applied granular compost of 5, 10 and 15 mm in diameter showed no significant difference from the pots applied chemical fertilizer or conventional compost.