Effect of different structure of fertilizer on the migration of nitrogen in red rice soil

The dynamic variation of different structures of fertilizers on N contents, forms in the soil flooding layer, leakage water of different depth, drain off water and soil profile in red rice soil were studied. The results showed that the forms of N in the soil flooding layer, leakage water and drain off water with different treatments mainly were NH4+-N and NO3--N, but the content of NH4+-N was higher than that of NO3--N. The concentration of N in the soil flooding layer of organic and inorganic fertilizers combined application was 1.18～1.20 times higher than that only inorganic fertilizers treatment during the early growth of rice. On the contrary, the latter was 1.11～1.21 times than the former during the late growth of rice. The N leaching loss in drain off water with different treatments was the highest at seedling stage, and the inorganic fertilizer treatment was higher than that organic and inorganic fertilizers mixed application. The downward migration of the NH4+-N was more obvious than that of alkaline-hydrogen N, and the quantity of organic and inorganic fertilizers combined was higher than that only inorganic fertilizer, but NO3--N was contrary to NH4+-N. The proportion of NO3--N in the leakage water at 50cm depth was higher than that at 30cm depth. The N leaching loss in leakage water was lower than that in drain off water of different treatments. The N input carried by water was much lower than output, and nitrogen loss was highest in the inorganic fertilizers treatment. The N unused by rice in inorganic fertilizer treatment was highest, and was 1.09 times of organic and inorganic fertilizer combined.