不同肥料结构对红壤稻田氮素迁移的影响

不同肥料结构对红壤稻田淹水层、不同深度渗漏水、外排水和土壤剖面中氮素的含量、形态及其动态变化的影响研究结果表明 ,各处理淹水层、外排水和渗漏水中NH4+-N含量明显高于NO3--N。淹水层中N的含量 ,水稻生育前期以单施化肥的高 ,约相当于配施有机肥的 1.18～ 1.20倍 ,而水稻生育后期 ,后者为前者的 1.11～ 1.2 1倍。各处理外排水中N素的输出量均以苗期最高 ,单施化肥明显大于配施有机肥。土壤剖面中NH4+-N向下迁移比碱解N更为明显 ,且配施有机肥的远高于单施化肥的 ,而NO3--N则相反。不同深度渗漏水中NO3--N的比例 ,上层 (30cm)低于下层 (50cm) ,随水逸出的N量各处理渗漏水均小于外排水 ;随水输入的N量远低于随水输出的N量 ,且以单施化肥的N亏损最大。水稻未利用的N量也以单施化肥的最大 ,约为配施有机肥的 1.0 9倍。

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.