Nitrogen and Phosphorus Dynamics and Pollution Risk of Potted Rice Treated with Manure from Livestock Farm

Combined with the nitrogen and phosphorus absorption by rice and their decomposing and releasing in water-soil environment, the rice capacity of treating and absorbing organic manure through applying different levels of pig manure and cattle manure to potted rice were studied.The results showed that the rice could deal with pig manure and cattle manure effectively. As ecological and economic benefits were considered comprehensively, P5 leve(lthe amount of pig manure was 120 000 kg·hm-2, which could be converted to 1 103.52 kg·hm-2 pure nitrogen)was the best treatment for treating pig manure and C6(the amount of cattle manure was 300 000 kg·hm-2, which could be converted to 3 224.5 kg·hm-2 pure nitrogen)was the best one for cattle manure. When the manure amount was lower than that, rice grew more slowly. When higher than that, yield-increasing effect was not significant and the plants were harmed easily while the risk of manure secondary pollution could increase.