Abstract
We investigated the effects of applying composted cattle manure on the leaching of nitrogen, phosphorus, and potassium from lysimeter paddies （W0.5×D1.0×h0.5m）, where forage rice （Oryza sativa L.）was cultivated from 2003to 2009. In 2007, we did not cultivate rice. In the years when rice was cultivated, nitrogen leaching increased with amount of the manure applied when adequate rainfall occurred between the application of manure and the commencement of irrigation. The amounts of nitrogen leaching from paddies during winter were equal or smaller than during the cultivation period. The amount of nitrogen leaching from the paddy to which 6kg/m2 （6M-plot） manure was applied was the highest. The amount of nitrogen leaching in the year without cultivation was significantly high. The effects of cultivation on phosphorus and potassium leaching were smaller than on nitrogen. Although the rice yield increased in the 6M-plot, the nutrients loss and the accumulation in the soil were the greatest. In the 2M-plot, the yield was higher than that in the 0M-plot, and nutrients loss and accumulation in the soil were as high as those in the 0M-plot. These results suggested that annual manure application at 2kg/m2 was preferable.
