地下滴灌对番茄根际微区氮循环微生物量及土壤N_(2)O排放的调控机制  

Regulation Mechanism of Subsurface Drip Irrigation on Nitrogen Circulating Microorganisms and N_(2)O Emission in Rhizosphere Microzone

作　　者：王京伟 李元[4] 牛文全[2,3] WANG Jingwei;LI Yuan;NIU Wenquan(College of Resources and Environment,Shanxi University of Finance and Economics,Taiyuan 030006,China;Institute of Soil and Water Conservation,Northwest A&F University,Yangling 712100,China;Institute of Soil and Water Conservation,CAS&MWR,Yangling 712100,China;Shaanxi Normal University,Xi′an 710119,China)

机构地区：[1]山西财经大学资源环境学院,山西太原030006 [2]西北农林科技大学水土保持研究所,陕西杨凌712100 [3]中国科学院水利部水土保持研究所,陕西杨凌712100 [4]陕西师范大学,陕西西安710119

出　　处：《环境科学研究》2021年第6期1425-1433,共9页Research of Environmental Sciences

基　　金：国家自然科学基金项目(No.51679205)。

摘　　要：为探明地下滴灌对番茄根际微区氮循环微生物及土壤N_(2)O排放的影响,采用静态暗箱原位采集法,研究了不同滴灌管埋深(0、10、20、30 cm,依次记为CK、S10、S20、S30处理)对番茄根区土壤水分、养分、根系形态、微生物及N_(2)O排放的影响.结果表明:S10处理可提高10~20 cm土壤含水率,其土壤NO_(3)^(-)-N含量、DOC(溶解性有机碳)含量、根系分叉数、开花坐果期反硝化菌数量、果实成熟期亚硝化菌和反硝化菌数量分别为CK处理的2.02、1.49、1.85、3.81、2.11和3.75倍(P<0.05),且0~20 cm土壤孔隙度较CK处理增加了10.72%(P<0.05),N_(2)O排放量为CK处理的1.99倍(P<0.05).S20处理显著提高了20~30 cm土壤含水率,其土壤NO_(3)^(-)-N含量、DOC含量、根系分叉数、开花坐果期反硝化菌数量、果实成熟期亚硝化菌和反硝化菌数量分别为CK处理的2.66、1.38、2.77、6.0、5.56和12.50倍(P<0.05),且0~20 cm土壤孔隙度较CK处理增加了22.32%(P<0.05),N_(2)O排放量为CK处理的2.24倍.S30处理形成0~20 cm土壤“干层”和20~40 cm土壤“湿层”,土壤NO_(3)^(-)-N含量、根系分叉数、开花坐果期亚硝化细菌和反硝化细菌数量分别为CK处理的1.66、2.22、2.00和1.80倍(P<0.05),但DOC含量、0~20 cm土壤孔隙度、反硝化细菌数量等显著低于S20处理(P<0.05),N_(2)O排放量与CK处理无显著差异(P<0.05).地下滴灌方式下土壤N_(2)O排放主要为反硝化作用,不同滴灌管埋深形成的土壤水分分布会影响根系分叉数和0~20 cm土壤孔隙度,调节NO_(3)^(-)-N和DOC含量、亚硝化细菌和反硝化细菌生物量,影响“根系-土壤-微生物”的交互作用和N_(2)O排放量.S10、S20处理下根区环境利于增强“根系-土壤-微生物”的交互作用、促进反硝化作用和N_(2)O排放,S30处理相对会减弱“根系-土壤-微生物”的交互作用、抑制N_(2)O排放.研究显示,地下滴灌管埋深(土壤供水位置)通过调节根际微区土壤环境,改变In order to determine the regulation mechanism of subsurface drip irrigation on soil nitrous oxide(N_(2)O)emissions and improve soil and water management measures,this work explored the effect of different depth of drip irrigation pipes(0,10,20 and 30 cm,i.e.CK,S10,S20 and S30)on soil microenvironment factors(moisture,nutrient and root morphology)and N_(2)O emission using the static opaque chamber method.In addition to the emission of soil N_(2)O,soil NH 4+-N and NO_(3)^(-)-N,dissolved organic carbon(DOC),0-20 cm soil porosity(SP),root forks number(RF),denitrifying bacteria(DB)and nitrite bacteria(NB)were measured.The effects of these factors on N_(2)O emission were quantitatively analyzed by the structural equation model.The results showed that S10 increased the moisture content of 10-20 cm soil.The contents of soil NO_(3)^(-)-N,DOC,RF,DB of flowering and fruit bearing period(FFBP),and NB and DB of fruits maturing period(FMP)in S10 were 2.02,1.49,1.85,3.81,2.11 and 3.75 times higher than that of CK(P<0.05),respectively.The SP in S10 was 10.72%greater than that of CK(P<0.05),and the total cumulative emissions of soil N_(2)O(T-N_(2)O)in S10 was 1.99 times higher than that of CK(P<0.05).S20 increased the moisture content of 20-30 cm soil.The contents of soil NO_(3)^(-)-N,DOC,RF,DB of FFBP,NB and DB of FMP in S20 were 2.66,1.38,2.77,6.0,5.56 and 12.5 times higher than that of CK(P<0.05),respectively.The SP in S20 was 22.32%higher than that in CK(P<0.05),and the T-N_(2)O in S20 was 2.24 times that of CK(P<0.05).S30 formed the‘dry layer’of 0-20 cm soil and the‘wet layer’of 20-40 cm soil.The contents of soil NO_(3)^(-)-N,RF,NB and DB of FMP in S30 were 1.66,2.22,2.00 and 1.80 times that of CK(P<0.05),respectively.The DOC,SP and DB of FFBP and FMP in S30 were significantly lower than those of S20(P<0.05),and there was no significant difference between T-N_(2)O in S30 and CK(P<0.05).The soil N_(2)O emission from subsurface drip irrigation was mainly caused by the denitrification process.Soil moisture distribution

关 键 词：地下滴灌 土壤N_(2)O 根区土壤 亚硝化细菌 反硝化细菌 

分 类 号：X506[环境科学与工程—环境工程]