本文選題：UV-B輻射　切入點：水分　出處：《環(huán)境科學(xué)》2017年11期

【摘要】：UV-B輻射對土壤碳氮轉(zhuǎn)化的影響與土壤物理化學(xué)性質(zhì)有關(guān),為明確土壤水分狀態(tài)對UV-B輻射的影響,以有機質(zhì)含量不同的兩個水稻土(有機質(zhì)含量低的記為L,高的記為H)為研究材料,在室內(nèi)研究了含水量為25%(W1)、50%(W2)和100%(W3)時,UV-B輻射對土壤總有機碳(TOC)、可溶性有機碳(DOC)、銨態(tài)氮(NH_4~+-N)、硝態(tài)氮(NO_3~--N)以及累積凈礦化氮量的影響.結(jié)果表明:120 h后,與避光(對照,CK)相比,UV-B輻射顯著降低了土壤TOC的含量(P0.05);UV-B輻射下,水分從低到高,L土壤的TOC分別降低了9.9%、4.5%和6.3%,H土壤降低了10.9%、5.6%和6.3%.但與對照相比,UV-B輻射卻促使土壤DOC增加;且在UV-B輻射下水分為100%的處理中,土壤DOC含量高于25%和50%的處理,120 h時,L土壤的DOC分別增加了21.5%(W1)、9.4(W2)和26.3%(W3),H土壤分別降低了26.7%(W1)、14.2%(W2)和33.8%(W3).與對照相比,UV-B輻射使NH_4~+-N含量有所下降;且在UV-B輻射中,NH_4~+-N含量的變化幅度在不同水分條件下的整體表現(xiàn)為W1W2W3.較對照處理,UV-B輻射促進NO_3~--N的累積,NO_3~--N變化幅度在不同水分條件下的表現(xiàn)為:W1W3W2.24 h后與對照相比,UV-B輻射對土壤累積凈礦化氮量有顯著影響(P0.05),且UV-B輻射下累積凈礦化氮量在不同水分之間差異顯著(P0.05).這表明光降解在土壤有機質(zhì)的穩(wěn)定中扮演著重要角色,UV-B輻射會加速土壤有機碳的損失,影響土壤礦質(zhì)態(tài)氮的轉(zhuǎn)化,且水分不同,UV-B輻射對土壤碳氮轉(zhuǎn)化的影響存在一定差異.
[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.
【作者單位】： 華中農(nóng)業(yè)大學(xué)資源與環(huán)境學(xué)院;湖北省襄陽市環(huán)境保護監(jiān)測站;華中農(nóng)業(yè)大學(xué)環(huán)境生態(tài)中心;
【基金】：國家重點基礎(chǔ)研究發(fā)展規(guī)劃(973)項目(2012CB417100) 中央高校基本科研業(yè)務(wù)費專項(2662016PY098)
【分類號】：S153

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