不同C/N入渗溶液对土壤氮素和盐分淋洗的影响

Effects of Different C/N Infiltration Solutions on Soil Nitrogen and Salt Leaching

采用土柱试验,对比研究了清水、再生水、不同C/N(7、16和20)的混合溶液入渗对土壤微生物及出流液溶质的影响。结果表明,溶液中C、N的存在和C/N的增大显著增加了壤土和砂土中细菌的数量,而对真菌无影响,同时壤土中细菌和真菌数量比砂土多。再生水入渗条件下壤土和砂土出流液NO-3-N质量浓度和EC均比清水大,加入C、N源后,壤土出流液NO-3-N质量浓度和EC随C/N的增大而增加,而在砂土中存在最佳的C/N,但入渗溶液中C、N的存在和C/N对壤土和砂土出流液NH+4-N的影响较小。秸秆还田、氮肥施用期间,农田应少灌再生水,避免氮素和盐分的淋失。

Soil column experiments were conducted to study the effect of clear water, reclaimed water, mixed solutions with C/N of 7, 16 and 20 on soil microorganism and soil solution solutes. The results showed that the existence of C, N and the increase of C/N significantly increased the number of bacteria both in loam and sandy soil, but had no effect on soil fungi, and the number of soil bacteria and fungi in loam was more than that in sandy soil. Compared with clear water infiltration, both NO3^- -N concentrations and EC were bigger in loam and sandy soil under reclaimed water infiltration. After adding C and N sources, both NO3^- -N concentrations and EC in the leaching solutions of loam soil increased with the increase of C/N in mixed infiltration solutions, but there was the optimal C/N to sandy soil. However, the existence of C, N and C/N in infiltration solutions had no effect on NH4^＋ -N in the leaching solutions of soil. It is suggested that irrigation water amount of reclaimed water should be reduced when agricultural measures, such as returning crop straw to soil and fertilization, are taken in order to avoid nitrogen and salt leaching.