稻田土壤溶液中溶解性有机氮、碳的空间分布及其微生物降解特性

Spatial distribution and microbial degradation characteristics of dissolved organic nitrogen and carbon in paddy soil solution

通过测坑定位试验,测定了稻田不同深度土壤溶液中溶解性有机氮（DON）、溶解性有机碳（DOC）的含量,并将原位提取的土壤溶液加入到人工土壤中,开展土壤溶液中DON、DOC的微生物降解试验,研究不同施肥处理DON、DOC的含量分布及其微生物降解特性。结果表明：（1）两种施肥处理0-10cm土壤溶液中TN、DON显著低于其他两层土壤;土壤溶液中DON占TN的比例均在62.9%-79.8%,为氮素组成的主要形式。（2）有机无机混合肥处理中DOC占TC的比例随土壤深度加大而逐渐增加,比例为21.1%-25.1%,而无机肥处理中DOC占TC比例则是逐渐下降,比例为18.9%-20.0%。（3）稻田土壤溶液中DON和DOC具有较好的微生物降解特性。降解28d后,DON占初始DON的30.1%-34.9%,而DOC占初始DOC的24.3%-28.2%。

Based on the lysimeter method,the contents of DON,DOC in paddy soil solution under different fertilization treatments were measured.At the same time,using the in situ microorganisms,microbial degradation experiments of soil solution were conducted to determined microbial degradation characteristics of DON and DOC.The results showed that TN and DON concentration in 0-10 cm soil solution were significantly lower than in other depths.The major nitrogen form in soil solution was DON,which contributed 62.9%-79.8%of TN.In the organic-inorganic mixed fertilizer treatment group（MT）,the contribution of DOC to TC increased obviously with increasing the soil depth,the DOC/TC rate of soil solution ranged 21.1%-25.1%.While in chemical fertilizer treatment group（CT）,the DOC/TC ratio decreased slowly with the increasing of soil depths and the range of DOC/TC was 18.9%-20.0%.DON,DOC in soil solution of rice field had high biodegradability,after 28-days microbial degradation,the concentration of DON and DOC in soil solution were only 30.1%-34.9%and 24.3%-28.2%of original value.