秸秆还田和添加生物炭对热带地区稻菜轮作体系中淹水后土壤温室气体排放的影响  

Effects of Straw Returning and Biochar Addition on Greenhouse Gas Emissions from High Nitrate Nitrogen Soil After Flooding in Rice-vegetable Rotation System in Tropical China

作　　者：胡天怡 车佳玥 胡煜杰 陈绮琦 张冬明 雷菲 曾建华 汤水荣 伍延正 孟磊[1] HU Tian-yi;CHE Jia-yue;HU Yu-jie;CHEN Qi-qi;ZHANG Dong-ming;Lei Fei;ZENG Jian-hua;TANG Shui-rong;WU Yan-zheng;MENG Lei(College of Tropical Crops,Hainan University,Haikou 570228,China;Agricultural Environment and Soil Research Institute,Hainan Academy of Agricultural Sciences,Haikou 571100,China;Scientific Observing and Experimental Station of Arable Land Conservation(Hainan),Ministry of Agriculture and Rural Affairs,Haikou 571100,China;Hainan Key Laboratory of Cultivated Land Preservation,Haikou 571100,China)

机构地区：[1]海南大学热带作物学院,海口570228 [2]海南省农业科学院农业环境与土壤研究所,海口571100 [3]农业农村部海南耕地保育科学观测试验站,海口571100 [4]海南省耕地保育重点实验室,海口571100

出　　处：《环境科学》2024年第3期1692-1701,共10页Environmental Science

基　　金：海南省自然科学基金青年基金项目(320QN196);国家自然科学基金项目(41807044,41661051,42067008);海南省耕地保育重点实验室开放课题项目(HAAS2022PT0103)。

摘　　要：热区稻菜轮作系统瓜菜季施肥后大量硝态氮积累,导致后续的水稻季淹水后硝态氮的淋失以及大量N_(2)O排放,使氮素损失以及温室效应加剧.如何提高硝态氮利用率,减少N_(2)O排放成为了亟待解决的问题.试验共设置6个处理:添加200 mg·kg^(-1)(以N计,下同)KNO_(3)(CK);添加200 mg·kg^(-1)KNO_(3)+2%生物炭(B);添加200 mg·kg^(-1)KNO_(3)和1%花生秸秆(P);添加200 mg·kg^(-1)KNO_(3)+2%生物炭+1%花生秸秆(P+B);添加200 mg·kg^(-1)KNO_(3)+1%水稻秸秆(R);添加200 mg·kg^(-1)KNO_(3)+2%生物炭+1%水稻秸秆(R+B),进行114 d的25℃恒温淹水培养,来探究有机物料添加对土壤淹水后温室气体排放和氮素利用的影响.结果表明,与CK相比,添加秸秆或秸秆和生物炭配施显著增加了土壤pH(P<0.05);B和P处理分别显著增加了41.6%和28.5%的N_(2)O累计排放(P<0.05),P+B、R和R+B处理分别显著降低了14.1%、24.7%和36.7%的N_(2)O累计排放(P<0.05);添加秸秆增加了净温室气体增温潜势(NGWP),增施椰壳生物炭能够显著减缓秸秆对NGWP的影响(P<0.05),秸秆和生物炭配合施用降低了NGWP,其中P+B显著降低NGWP(P<0.05),R+B不显著;添加秸秆或生物炭显著增加了土壤微生物量碳(MBC)(P<0.05),P+B最高,为502.26mg·kg^(-1);秸秆和生物炭配施增加了土壤微生物量氮(MBN),P+B最高.N_(2)O排放通量与pH呈极显著负相关(P<0.01),与NH_(4)^(+)-N和NO_(3)^(-)-N呈极显著正相关(P<0.01);N_(2)O累计排放量与MBN呈极显著负相关(P<0.01);NO_(3)^(-)-N与MBN呈显著负相关(P<0.05),说明硝态氮的减少可能被微生物固持,微生物对硝态氮固持的增加也减少了N_(2)O排放.综上所述,花生秸秆和椰壳生物炭配合施用能够显著抑制N_(2)O排放,增加土壤MBC和MBN,是一种海南瓜菜季后充分利用氮肥,减少氮素损失,减缓N_(2)O排放的一种合理措施.In rice-vegetable rotation systems in tropical areas,a large amount of nitrate nitrogen accumulates after fertilization in the melon and vegetable season,which leads to the leaching of nitrate nitrogen and a large amount of N_(2)O emission after the seasonal flooding of rice,which leads to nitrogen loss and intensification of the greenhouse effect.How to improve the utilization rate of nitrate nitrogen and reduce N_(2)O emissions has become an urgent problem to be solved.Six treatments were set up[200 mg·kg^(−1) KNO_(3)(CK);200 mg·kg^(−1) KNO_(3)+2%biochar addition(B);200 mg·kg^(−1) KNO_(3)+1%peanut straw addition(P);200 mg·kg^(−1) KNO_(3)+2%biochar+1%peanut straw addition(P+B);200 mg·kg^(−1) KNO_(3)+1%rice straw addition(R);200 mg·kg^(−1) KNO_(3)+2%biochar+1%rice straw addition(R+B)]and cultured at 25℃for 114 d to explore the effects of organic material addition on greenhouse gas emissions and nitrogen use after flooding in high nitrate nitrogen soil.The results showed that compared with that in CK,adding straw or combining straw with biochar significantly increased soil pH(P<0.05).The B and P treatments significantly increased the cumulative N_(2)O emissions by 41.6%and 28.5%(P<0.05),and the P+B,R,and R+B treatments significantly decreased the cumulative N_(2)O emissions by 14.1%,24.7%,and 36.7%(P<0.05),respectively.The addition of straw increased the net warming potential of greenhouse gases(NGWP).The addition of coir biochar significantly reduced the effect of straw on NGWP(P<0.05).The combined application of straw and biochar decreased NGWP,and P+B significantly decreased NGWP,but that with R+B was not significant(P>0.05).Adding straw or biochar significantly increased soil microbial biomass carbon(MBC)(P<0.05),and that of P+B was the highest(502.26 mg·kg^(−1)).The combined application of straw and biochar increased soil microbial biomass nitrogen(MBN),and that of P+B was the highest.The N_(2)O emission flux was negatively correlated with pH(P<0.01)and positively correlated with NH_(4)

关 键 词：生物炭 秸秆 氧化亚氮(N_(2)O) 土壤微生物量碳氮 硝态氮 

分 类 号：X16[环境科学与工程—环境科学]