控制条件下水肥耦合对黄泥田还田秸秆腐解及土壤碳转化的影响  

Effect of soil moisture and nitrogen fertilizer on the decomposition of straw returned to field and the transformation of carbon under controlled conditions

作　　者：苏朋[1] 傅昱[1] 何艳[1] 徐建明[1] 吴建军[1] 吴良欢[1] 

机构地区：[1]浙江大学环境与资源学院,浙江省亚热带土壤与植物营养重点实验室,浙江杭州310058

出　　处：《植物营养与肥料学报》2015年第1期1-11,共11页Journal of Plant Nutrition and Fertilizers

基　　金：国家公益性行业(农业)科研专项项目(201003016);国家重点基础研究发展973计划项目(2011CB100502);国家科技支撑计划课题(2012BAD15BO4-2)联合资助

摘　　要：【目的】研究秸秆还田后不同水温和肥剂管理措施下土壤碳素转化特征。【方法】以华中双季稻区低产水稻土黄泥田为供试材料,模拟早稻和晚稻秸秆还田的田间环境,在实验室控制条件下,开展了两种温度环境中(15℃、35℃)不同水分(40%和100%最大田间持水量,即40%WHC、100%WHC)、配施氮肥类型(尿素、猪粪即U、M)、以及促腐菌剂添加对秸秆腐解效果及其过程中土壤碳素转化影响的研究。对水稻秸秆腐解过程中土壤CO2释放量、以及土壤可溶性有机碳(DOC)和总有机碳(TOC)含量在105天培养周期内变化特征进行动态监测分析。【结果】两种温度环境中整个培养周期内,各处理的CO2释放速率和释放总量通常表现为100%WHC-M>100%WHC-U>40%WHC-M>40%WHC-U,即猪粪优于尿素的规律,而不论配施何种氮肥都存在100%WHC>40%WHC(P<0.01)的现象,同时40%WHC条件下辅施菌剂可显著提升CO2释放量;与此相反,两种温度环境下DOC含量都表现为40%WHC-M>40%WHC-U>100%WHC-M>100%WHC-U(后两者差异小),即40%WHC条件下DOC含量显著高于100%WHC(P<0.05),且配施猪粪处理优于配施尿素处理,但这两种氮肥处理间差异随培养时间延长而减小;以CO2-C释放量计算0 7 d、0 28 d、0 105 d内物料分解率,结果表明,35℃时100%WHC-U的处理中物料分解最快,15℃时40%WHC-M的处理中物料分解最慢。与之对应,105 d内TOC含量和净增量则在35℃时100%WHC-U的处理中最小(P<0.01),而在15℃时40%WHC-M的处理中最大(P<0.01);TOC的净增量和净损失量在相同温度条件下,尤其试验前期不同水分(P<0.01)、氮素(P<0.05)间均存在显著差异,且促腐菌剂添加普遍减小TOC含量;培养周期内所有处理的CO2释放速率与DOC含量间存在显著相关(P<0.05)。【结论】水分状况对碳素的转化存在极大影响,其次是氮肥类型,且氮肥的影响作用随秸秆还田时间的延长而减弱;高湿条件更利于促进秸秆腐解,但导致土�【Objectives】To study the effect of soil moisture and nitrogen fertilizer on the decomposition of straw returned to field and the transformation of soil carbon( C). 【Methods 】We investigated impacts of moisturecontent [40% vs. 100% of water holding capacity( WHC) ],N fertilizer [urea( U) vs. pig manure( M) ],and supplementary addition of decay-facilitating microbial inocula on the decomposition of straw residues and soil C transformation using a low yield yellow-paddy soil in double rice cropping area,central China. A controlled laboratory experiment was conducted in two temperature( 15℃ vs. 35℃) regimes with a total incubation period of105 days. During the period,CO2,dissolved organic carbon( DOC) and total organic carbon( TOC) were monitored periodically. 【Results 】 In general, under both temperature regimes, the CO2 release rate and cumulative CO2 emission were in a order of 100% WHC- M > 100% WHC- U > 40% WHC- M > 40% WHC-U. Those treatments added with manure were higher than with urea,those treatments under 100% WHC were always higher than those under 40% WHC( P < 0. 01),regardless of N fertilizer,in which microbial inoculation significantly improved CO2 emissions. On the contrary,DOC contents of treatments under two temperatures followed a sequence of 40% WHC- M > 40% WHC- U > 100% WHC- M > 100% WHC- U,namely DOC contents detected under condition of 40% WHC were significantly higher than 100% WHC( P < 0. 05),and treatments with manure had higher DOC contents than those with urea but accompanied by a decreasing difference between them.Material decomposition ratio during the 0- 7 d,0- 28 d and 0- 105 d,which were calculated by CO2 release,showed the maximum value in 35℃- 100% WHC- U while the minimum value in 15℃- 40% WHC- M.Additionally,TOC contents and net TOC increment were the least in 35℃-100% WHC- U( P < 0. 01) while the largest in 15℃- 40% WHC- M( P < 0. 01); net TOC increment and net TOC loss were different in different moisture contents( P < 0. 01) and nitrogen( P < 0. 05) when

关 键 词：碳素转化 水温肥剂耦合管理 秸秆快腐 低产水稻土 培肥 固碳 

分 类 号：S141.4[农业科学—肥料学]