中文摘要：

中国每年农作物秸秆总量巨大,大部分农民选择焚烧,焚烧秸秆会减少表层土壤有机质,损害土壤墒情,引起环境污染,进而危害人类健康。将玉米秸秆施入土壤亚表层（20～40 cm之间）,即＂秸秆深还＂（Corn stover deep incorporation,CSDI）,可以有效解决秸秆利用问题,以及由于焚烧秸秆造成的诸多问题,继而达到固碳、蓄水、培肥、稳产的目的。以吉林农业大学试验站玉米连作耕地0～20 cm和20～40 cm土层土壤为研究对象,设CK（未施用秸秆）、CS（秸秆深还）、NPK（单施化肥）、CS＋NPK（秸秆深还配施化肥）4种处理,主要研究秸秆深还及配施化肥对土壤腐殖质组成和胡敏酸（HA）结构的影响。腐殖质组成采用腐殖质组成修改法测定,胡敏酸样品采用IHSS方法提取纯化,其结构经元素组成、红外光谱进行研究。结果表明：秸秆深还及秸秆配施化肥对不同土层土壤有机碳（SOC）含量以及腐殖质各组分含碳量均有显著积累作用,PQ值（胡敏酸在腐殖酸中所占的比例）无显著变化。秸秆深还及秸秆配施化肥均能使HA分子的芳香结构比例增加,但CS处理还能同时增加脂族链烃的比例;而CS＋NPK处理则使HA的缩合度提高,氧化度下降。说明CS和CS＋NPK使HA变稳定的机制有所不同,除了分子结构芳香性提高的作用以外,前者还体现在疏水性的提高上;而后者则体现在分子结构变复杂上。

英文摘要：

Every year China produces huge volumes of crop straw,most of which,however,is burnt by the farmers in the fields. Burning of straw in open fields will not only reduce the contents of soil organic matter and soil moisture in the surface soil layer,but also bring about environment pollution and damage human health. To apply corn stover deep into the subsoil layer（20～40 cm）,namely＂Corn stover deep incorporation＂（CSDI）,is believed to be able to effectively solve the problem of how to utilize crop residue as resource and a number of other problems caused by burning of crop straw and further on help sequestrate carbon,raise water holding capacity,improve soil fertility and stabilize crop yield. A field experiment was conducted in a mono-cropping corn field at the Experiment Station of the Jilin Agricultural University,with four treatments,that is,CK（no-corn stover incorporated）,CS（CSDI）,NPK（fertilizers applied only）CS＋NPK（CSDI plus fertilizers application）designed to explore effects of corn stover deeply incorporated in addition to fertilizers application on composition of soil humus and structure of humic acid（HA）in the soil. Soil samples were collected from the four treatments for analysis of humus composition with the modified humus component extraction method and for structure of HA with the IHSS method for purification and the infrared spectroscopy for element composition. Results show that treatments CS and CS＋NPK were conducive to accumulation of SOC and various humus fractions in all soil layers,but did not affect PQ（percentage of humic acid in humus）much. The two treatments increased the proportion of aromatic-C in HA,and Treatment CS also increased the proportion of aliphatic chain hydrocarbon in HA,while treatment CS＋NPK raised the condensation degree and lowered the oxidation degree of HA,which means the two treatments differed in mechanism of making HA stable. Besides their effects of improving the aromaticity of HA in molecular structure,Treatment CS also enhanc