不同水分管理条件下添加生物炭对琼北地区水稻土N_(2)O排放的影响  

Effects of Biochar Addition Under Different Water Management Conditions on NO Emission From Paddy Soils in Northern Hainan

作　　者：王鸿浩 谭梦怡 王紫君 符佩娇 李金秋 汤水荣 伍延正 孟磊[1] WANG Hong-hao;TAN Meng-yi;WANG Zi-jun;FU Pei-jiao;LI Jin-qiu;TANG Shui-rong;WU Yan-zheng;MENG Lei(College of Tropical Crops,Hainan University,Haikou 570228,China)

机构地区：[1]海南大学热带作物学院,海口570228

出　　处：《环境科学》2021年第8期3943-3952,共10页Environmental Science

基　　金：海南省自然科学基金高层次人才项目(2019RC049);国家自然科学基金项目(41661051,42067008)。

摘　　要：干湿交替会影响土壤硝化和反硝化等N_(2)O主要的产生过程,频繁的干湿交替在以海南为代表的热带水稻种植地区十分常见.生物炭作为一种土壤改良剂在改良土壤理化性质,减少土壤温室气体排放方面应用广泛,然而当前关于生物炭在琼北地区水稻土频繁干湿交替过程中减排效果研究并未深入.本试验以海南琼北地区典型水稻土为供试土壤,以400℃厌氧条件下炭化的玉米秸秆生物炭为供试生物炭,探究不同水分管理条件下添加生物炭对土壤温室气体排放及微生物相关功能基因的影响.试验设置干湿交替条件下不添加生物炭(AWD1),干湿交替并添加2%生物炭(AWD2),干湿交替并添加4%生物炭(AWD3),持续淹水不添加生物炭(CF1),持续淹水并添加2%生物炭(CF2),持续淹水并添加4%生物炭(CF3)共6个处理,进行为期30 d的25℃恒温避光培养.结果表明:(1)不同水分条件下添加玉米秸秆生物炭均可减少酸性水稻土中N_(2)O的排放(P<0.05,下同),AWD3处理N_(2)O排放总量为0.43 mg·kg^(-1),相比AWD1处理减少了68%;(2)玉米秸秆生物炭在不同水分管理条件下均可以显著提高土壤pH,添加生物炭处理相对于不添加生物炭处理在培养结束后土壤pH平均提高了0.5个单位,同时提高土壤NH_(4)^(+)-N含量,但会导致Eh的降低;(3)玉米秸秆生物炭的添加显著降低了氨氧化细菌(AOB)丰度,显著提高了nosZ基因丰度,降低了(nirK+nirS)/nosZ的比值,抑制了硝化过程,同时促进了反硝化过程N_(2)O的还原,从而降低了N_(2)O排放.结果表明,干湿交替过程添加生物炭有利于减少水稻田土N_(2)O排放,在琼北地区农业温室气体减排方面有较大的应用前景.Alternating dry and wet conditions affect the main processes of N_(2)O production,such as nitrification and denitrification.Such conditions are very common in tropical rice-growing areas,such as Hainan.As a type of soil amendment,biochar is widely used to improve physical and chemical properties of soil and to reduce soil greenhouse gas emissions.However,there is a lack of existing indepth research on the emission reductions of biochar when used in tropical soils that undergo frequently alternating dry and wet conditions.In this experiment,typical paddy soil from northern Hainan was used as the test soil,and corn stalk biochar,carbonized under anaerobic conditions at 400℃,was used as the test biochar.This experiment explored the effects of adding biochar on soil greenhouse gas emissions and microbial-related functional genes under different water management conditions.The experiment comprised a 30 d culture,kept in the dark at 25℃,and a total of six treatments:alternating dry-wet conditions without adding biochar(AWD1),alternating dry-wet conditions with 2%biochar (AWD2),alternating dry-wet conditions with 4%biochar (AWD3),continuous flooding without adding biochar (CF1),continuous flooding with 2%biochar (CF2),and continuous flooding with 4%biochar (CF3).The results showed that:(1) the addition of biochar under different moisture conditions can reduce N_(2)O emissions in acidic paddy soil (P<0.05,the same below),as the total N_(2)O emissions with the AWD3 treatment were 0.43 mg·kg^(-1),which indicates an approximate reduction of 68%,relative to the AWD1 treatment;(2) Corn stalk biochar can significantly increase the soil pH under different water management conditions.Compared to the no-biochar treatment,the soil pH increased by 0.5 units on average after cultivation with the addition of biochar,and as the soil NH_(4)^(+)-N content increased,it led to a decrease in Eh.(3) Corn stalk biochar significantly reduces the abundance of ammonia oxidizing bacteria and significantly increases the nos Z gene abundance.

关 键 词：干湿交替 持续淹水 生物炭 N_(2)O 氨氧化细菌(AOB) (nirK+nirS)/nosZ 

分 类 号：X16[环境科学与工程—环境科学]