不同水分梯度下UV-B辐射对2个稻田土壤碳氮转化的影响

发布时间：2018-04-01 06:37

本文选题：UV-B辐射　切入点：水分　出处：《环境科学》2017年11期

【摘要】：UV-B辐射对土壤碳氮转化的影响与土壤物理化学性质有关,为明确土壤水分状态对UV-B辐射的影响,以有机质含量不同的两个水稻土(有机质含量低的记为L,高的记为H)为研究材料,在室内研究了含水量为25%(W1)、50%(W2)和100%(W3)时,UV-B辐射对土壤总有机碳(TOC)、可溶性有机碳(DOC)、铵态氮(NH_4~+-N)、硝态氮(NO_3~--N)以及累积净矿化氮量的影响.结果表明:120 h后,与避光(对照,CK)相比,UV-B辐射显著降低了土壤TOC的含量(P0.05);UV-B辐射下,水分从低到高,L土壤的TOC分别降低了9.9%、4.5%和6.3%,H土壤降低了10.9%、5.6%和6.3%.但与对照相比,UV-B辐射却促使土壤DOC增加;且在UV-B辐射下水分为100%的处理中,土壤DOC含量高于25%和50%的处理,120 h时,L土壤的DOC分别增加了21.5%(W1)、9.4(W2)和26.3%(W3),H土壤分别降低了26.7%(W1)、14.2%(W2)和33.8%(W3).与对照相比,UV-B辐射使NH_4~+-N含量有所下降;且在UV-B辐射中,NH_4~+-N含量的变化幅度在不同水分条件下的整体表现为W1W2W3.较对照处理,UV-B辐射促进NO_3~--N的累积,NO_3~--N变化幅度在不同水分条件下的表现为:W1W3W2.24 h后与对照相比,UV-B辐射对土壤累积净矿化氮量有显著影响(P0.05),且UV-B辐射下累积净矿化氮量在不同水分之间差异显著(P0.05).这表明光降解在土壤有机质的稳定中扮演着重要角色,UV-B辐射会加速土壤有机碳的损失,影响土壤矿质态氮的转化,且水分不同,UV-B辐射对土壤碳氮转化的影响存在一定差异.
[Abstract]:The effect of UV-B radiation on soil carbon and nitrogen conversion is related to the physical and chemical properties of soil. Two paddy soils with different organic matter contents (low organic matter and high H) were used as the research materials. The effects of UV-B radiation on soil total organic carbon (TOC), soluble organic carbon (DOC), ammonium nitrogen (NH _ 4 ~ -N ~ -N), no _ 3-N (no _ 3-N) and accumulated net mineralized nitrogen (N _ 2O _ 3) were studied in the laboratory when the water content was 25% W _ (1) and 100% W _ (3). The results showed that the total organic carbon (TOC), soluble organic carbon (DOC), ammonium nitrogen (NH _ 4 ~ -N), no _ 3-N (no _ 3-N) and the accumulation of net mineralized nitrogen were increased after 120 h. Compared with CK, UV-B radiation significantly decreased the content of TOC in soil. Under UV-B radiation, the TOC of soil from low to high level decreased by 9.9% and 6.33%, respectively. However, compared with the control, UV-B radiation promoted the increase of soil DOC. In the treatment with 100% UV-B radiation, the content of DOC in soil was increased by 21.5W _ (1) 9.4W _ (2) and 26.3W _ (3) C _ (2) and 33.8W _ (3) respectively when the DOC content was higher than 25% and 50% for 120 h. Compared with the control, the content of NH _ 4 ~ -N was decreased by UV-B radiation. The variation range of NH4- N content in UV-B radiation was W1W2W3 under different water conditions. Compared with the control treatment, UV-B radiation promoted the accumulation of NO_3~--N. The change range of N in different water conditions was as follows: W1W3W2.24 h after compared with the control. Radiation has a significant effect on the accumulation of net mineralized nitrogen in soil, and the accumulation of net mineralized nitrogen under UV-B radiation is significantly different among different water contents. This indicates that photodegradation plays an important role in the stabilization of soil organic matter by UV-B radiation. Soil organic carbon loss, The transformation of soil mineral nitrogen was affected, and the effect of different water content on soil carbon and nitrogen conversion was different.
【作者单位】：华中农业大学资源与环境学院;湖北省襄阳市环境保护监测站;华中农业大学环境生态中心;
【基金】：国家重点基础研究发展规划(973)项目(2012CB417100) 中央高校基本科研业务费专项(2662016PY098)
【分类号】：S153

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