中文摘要：

秸秆深还（Corn stover deep incorporation，CSDI）指将作物秸秆深埋于土壤亚表层20~40 cm深处，用以解决秸秆焚烧和土壤肥力退化的可持续利用模式。本文以吉林农业大学玉米连作耕地试验田未施用秸秆和秸秆深还不同年限的土壤为研究对象，设置CK、CSDI（2014）、CSDI（2013）和CSDI（2012）共4种处理，分别代表未施入秸秆、2014年秸秆深还（深还第1年）、2013年秸秆深还（深还第2年）、2012年秸秆深还（深还第3年）。研究秸秆深还不同年限对黑土腐殖质组成和胡敏酸结构特征的影响。通过腐殖质组成修改法提取富里酸（Fulvic acid，FA）、胡敏酸（Humic acid，HA）和胡敏素（Humin，HM），国际腐殖质协会（International Humic Substances Society，IHSS）推荐的方法提取HA样品，通过元素组成、红外光谱和差热分析测定HA结构。结果表明：与CK相比，秸秆深还1年后显著提高了土壤和腐殖质各组分有机碳含量，亚表层累积效果更明显，其土壤有机碳（SOC）、HA、FA和HM有机碳含量分别增加了23.7%、30.5%、27.3%和46.1%，但PQ值（HA在可提取腐殖物质的比例）没有显著变化；HA氧化度和缩合度降低明显，表层和亚表层（O＋S）/ C比值分别降低14.31 %和14.68 %，H/C比值分别增加27.74 %和28.86 %，脂族链烃和芳香碳含量增加，热稳定性降低，HA结构趋于简单化。随着年限增加，深还3年后SOC、FA和HM有机碳含量呈下降趋势，HA有机碳含量呈上升趋势，PQ值变化显著，HA缩合度、氧化度呈上升趋势，脂族性减弱，芳香性增强，HA结构趋于复杂化。说明随着年限增加，秸秆不断矿化分解，秸秆深还对土壤腐殖质组成和结构特征的影响效果减弱。

英文摘要：

【Objective】How to reasonably use of corn stover has become an important topic in the agricultural regions of China. Corn stover incorporation into the field is the best way in corn stover utilization. However, the method of corn stover incorporation used to either overcast the corn stover on the surface of the field like mulching or incorporate the corn stover into the shallow topsoil layer, which would obviously bring about some problems, like impeding rise of soil temperature, seedling growth, favoring incidence of insect pests. Corn stover deep incorporation （CSDI） refers to burying corn stover deeply into the subsoil layer and it is believed to be a sustainable utilization model to solve the problem of burning of corn stover and degradation of soil fertility. But with the days going on, it is not clear that the dynamic change in composition and structural characteristics of soil humus caused by CSDI. This paper mainly deals with the effect of the corn stover applied duration on components of soil humus and structural characteristics of humic acid in the soil, so as to provide some theoretical basis for determining the interval of CSDI.【Method】A field experiment was conducted in a mono-cropping corn field of black soil at the Experiment Station of the Jilin Agricultural University, with four treatments, that is, CK （No corn stover incorporated）, CSDI-2014 （One year after the corn stover deep incorporation）, CSDI-2013 （Two years after the corn stover deep incorporation） and CSDI-2012 （Three years after the corn stover deep incorporation）. Humus, including fulvic acid （FA）, humic acid （HA） and humin （HM） with the modified humus component extraction method for analysis of composition and then HA was further extracted with the IHSS method for analysis of element composition, infrared spectrum, thermogravimetry, and structure with differential thermal analysis. 【Result】Results show that in Treatment CSDI-2014 significantly increases the content of organic carbon by 23.7%,