秸秆腐解菌剂和微生物产电过程对稻田土壤温室气体排放的影响

发布时间：2018-05-17 12:52

本文选题：稻田土壤 + 温室气体　；参考：《南京师范大学》2015年硕士论文

【摘要】：我国是世界上重要的农业大国,每年产生大量的农作物秸秆,秸秆是非常丰富、廉价且易于获取的自然资源,如何合理地将这些资源利用起来,既使资源得到充分合理的利用,又使环境不会遭受污染和破坏,成为现代农业面临的一大难题。秸秆还田能有效提升土壤肥力,因而被广泛认可,但也存在着显著增加温室气体排放的弊端。因此,寻找秸秆还田条件下合适的减排措施有很重要的意义。本文研究了添加不同秸秆腐解菌剂处理、纤维素酶处理,秸秆腐解速度的差异和土壤CH4和CO2排放通量的差异,明确秸秆腐解菌剂和纤维素酶对土壤CH4和CO2排放的影响。其主要结果如下：(1)不同秸秆腐解菌剂对秸秆腐解的影响存在很大差异,本研究中“瑞莱特”微生物催腐剂(RL)对秸秆腐解的促进作用最明显,且CH4累积排放量与60d后秸秆失重率显著正相关(R=0.491,p0.05),60d后秸秆失重率与CO2累积排放量无显著相关性。在温室培养条件下,本研究中使用的几种秸秆腐解菌剂均对秸秆腐解无显著的促进作用；秸秆腐解菌剂与纤维素酶联用也对秸秆腐解无显著的促进作用,同时显著增加了CH4和CO2的排放(p0.05)。(2)在不同温度下,相比于对照组(CKh),“金葵子”腐秆剂(JKh)中的微生物更能适应40℃的高温条件,能在该条件下显著提高秸秆失重率(p0.05),有效发挥促进腐解作用,且能显著减少CH4和CO2排放(p0.05)。另外,本文设置了连接不同外阻和添加不同量秸秆的微生物燃料电池(MFC)用于微生物产电,测量了土壤CH4和CO2排放通量的差异,分析了不同实验条件下产甲烷古菌和甲烷氧化细菌的丰度,以及运行MFC后土壤理化性质的差异,明确微生物产电过程对土壤CH4和CO2排放的影响,及其微生物学机理。其主要结果如下：(1)MFC连接的外阻越小CH4排放峰值越低、累积排放量越少,CH4的30d累积排放量与MFC连接的外阻呈极显著相关(R=0.817,p0.01)；MFC连接不同外阻CO2排放峰值和累积排放量均无显著差异,CO2的30d累积排放量与MFC连接的外阻也没有显著相关关系(p0.05)。(2)CH4的排放与秸秆添加量有极显著正相关(开路组OC：R=0.941,p0.01；闭路组CC：R=0.946,p0.01),CO2的排放与秸秆添加量也有显著正相关(开路组OC：R=0.871,p0.05；闭路组CC：R=0.785,p0.05,)；另外,与开路相比,运行添加0.5%秸秆MFC可显著减少CH4累积排放量47.43%(p0.05),不添加秸秆无显著差异,添加1%秸秆和添加2%秸秆的MFC则分别显著增加CH4排放52.05%和131.07%(p0.05)；运行MFC对CO2排放无显著影响。(3)相同秸秆添加量的开路组与闭路组之间产甲烷古菌丰度无显著差异(p0.05),秸秆添加量为0.5%的开路组与闭路组之间甲烷氧化细菌丰度也无显著差异(p0.05),但秸秆添加量为2%的开路组(OC4)甲烷氧化细菌丰度显著高于对应的闭路组(CC4),因此在秸秆添加量为0.5%时,MFC对CH4的减排效应占主导,在秸秆添加量为2%时,MFC对CH4氧化的抑制效应占主导。同时,本文研究了在盆栽水稻条件下添加不同量秸秆MFC土壤CH4和CO2排放通量的差异,分析添加不同量秸秆条件下运行MFC后土壤理化性质的差异,来明确盆栽水稻条件下MFC对土壤CH4和C02排放的影响,以及放大实验规模和种植水稻对CH4和CO2排放规律是否会产生影响。结果显示,盆栽水稻条件下结果与未种植水稻时相似,同时,运行MFC对水稻生长无显著影响。本研究明确了秸秆腐解菌剂和纤维素酶对土壤CH4和CO2排放的影响；明确了微生物产电过程对土壤CH4和C02排放的影响,及其微生物学机理。为秸秆还田条件下温室气体的减排提供了新的思路和方法。
[Abstract]:The results are as follows : ( 1 ) The results are as follows : ( 1 ) The effect of straw decomposition agent and cellulase on soil CH4 and CO2 emission is significant .
The results are as follows : ( 1 ) The lower the external resistance of MFC connection , the lower the emission peak of CH4 and CO2 , the lower the cumulative emissions , the lower the cumulative emission of CH4 and the external resistance of MFC connection ( R = 0.817 , p0.01 ) .
There was no significant difference between CO2 emission peak and cumulative emission of MFC connection . There was no significant correlation between the emission of CO2 and the external resistance of MFC connection ( p < 0.05 ) . ( 2 ) CH4 emission was positively correlated with straw addition ( open group OC : R = 0.941 , p0.01 ) ;
CC : R = 0.946 , p0.01 ) , CO2 emission was positively correlated with straw addition ( open group OC : R = 0.871 , p0.01 ) ;
Closed group CC : R = 0.785 , p0.05 , ) ;
In addition , compared with the open circuit , the addition of 0.5 % straw MFC could significantly reduce CH4 cumulative emission by 47.43 % ( p < 0.05 ) , without significant difference of straw , adding 1 % straw and MFC with 2 % straw significantly increased CH4 emission by 52.05 % and 131.07 % ( p0.05 ) , respectively ;
( 3 ) There was no significant difference in CH4 and CO2 emission between open - circuit group and closed - circuit group ( p . 05 ) .
The effects of microbial production process on CH4 and CO2 emission in soil and its microbiology mechanism are clarified . The new ideas and methods are provided for reducing greenhouse gas emission under the condition of straw return .
【学位授予单位】：南京师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X172;X712

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