秸秆深还对土壤团聚体中腐殖质组成与结构特征的影响

发布时间：2018-12-27 17:35

【摘要】：传统的秸秆还田存在着影响种子发芽生长、土壤升温慢和病虫害增加等问题。秸秆深还(Deep application of straw,DAS)不仅能解决秸秆焚烧的问题,还能达到保碳、蓄水、培肥、稳产的目的,使秸秆还田得到改善。探究秸秆深还对土壤腐殖质的影响,可以为如何提高土地肥力、如何利用秸秆深还创建合理耕层提供理论依据。本试验以黑土和潮褐土为研究对象,采用湿筛法将其分为2mm、2~0.25mm、0.25~0.053mm和0.053mm这4个粒级,通过腐殖质组成修改法确定土壤腐殖质各组分有机碳含量,提取土壤胡敏酸(HA)和胡敏素(Hu),通过元素组成、红外光谱和差热分析确定HA和Hu的结构特征,从而确定秸秆深还对土壤团聚体中腐殖质组成与结构特征的影响。结果表明:(1)黑土和潮褐土优势粒级是2~0.25mm粒级,黑土优势粒级含量是表层低于亚表层。秸秆深还(DAS)促使黑土优势粒级增加,潮褐土2个大粒级增加。(2)黑土有机碳含量一般高于潮褐土。黑土对照、潮褐土对照和其深施秸秆800kg/667m2处理中有机碳含量都是表层高于亚表层。秸秆深还促使黑土和潮褐土中有机碳含量增加。(3)潮褐土团聚体中FA、HA和Hu有机碳含量最大值分别存在于0.053mm、2~0.25mm和2mm粒级,PQ最大值在2~0.25mm粒级。随秸秆深还量的增加,HA、Hu含碳量和PQ由表层大于亚表层变为表层低于亚表层。秸秆深还有利于亚表层HA和Hu含碳量积累,PQ值升高,腐殖化程度升高,腐殖质品质得到改善。(4)黑土对照土壤中HA的含碳量和缩合度高于潮褐土,氧化度低于潮褐土,黑土HA品质优于潮褐土。潮褐土2~0.25mm粒级的含碳量最大,氧化度最小;0.053mm粒级与之相反。与亚表层相比,黑土和潮褐土表层中HA的平均含碳量都高于亚表层,氧化度都低于亚表层,此外黑土缩合度和热稳定性低于亚表层,脂族碳/羧基碳和脂族碳/芳香碳高于亚表层,表层HA的结构更简单、年轻。秸秆深还促使黑土和潮褐土HA的氧化度降低,黑土的缩合度和热稳定性下降。(5)黑土Hu的含碳量、缩合度比相应的HA高,氧化度较低。秸秆深还促使黑土表层和亚表层团聚体中Hu的氧化度和稳定性降低,脂族链烃减少,活性结构增多,Hu的结构趋于简单化、年轻化。
[Abstract]:The traditional straw returning to the field has some problems such as the influence of seed germination, slow soil temperature rise and the increase of diseases and pests. Straw depth and (Deep application of straw,DAS) can not only solve the problem of straw burning, but also achieve the purpose of carbon conservation, water storage, fertilization and stable production, which can improve the return of straw to the field. Exploring the effect of straw depth on soil humus can provide theoretical basis for how to improve soil fertility and how to make use of straw depth to create rational tilling layer. In this experiment, the black soil and the tidal cinnamon soil were divided into four grain-grades of 2mm ~ 2mm ~ 0.25mm ~ 0.25mm ~ 0.25mm ~ 0.053mm and 0.053mm by wet sieve method. The content of organic carbon of soil humus components was determined by humus composition modification method. (HA) and humin (Hu), were extracted from soil by elemental composition, IR and DTA to determine the structural characteristics of HA and Hu, so as to determine the effect of straw depth on the composition and structural characteristics of humus in soil aggregates. The results showed that: (1) the dominant grain-size of black soil and tidal cinnamon soil was 2~0.25mm grade, and the dominant grain-level content of black soil was lower than that of subsurface layer. Straw depth and (DAS) also promoted the increase of dominant grain grade in black soil and the increase of two large grain levels in fluvo-cinnamon soil. (2) the organic carbon content of black soil was generally higher than that of fluvo-cinnamon soil. The content of organic carbon in the black soil, the fluvo-cinnamon soil and the 800kg/667m2 treatment was higher in the surface layer than in the subsurface layer. Straw depth also increased the content of organic carbon in black soil and tidal cinnamon soil. (3) the maximum content of FA,HA and Hu in aggregates of Chao cinnamon soil was 0. 053 mm and 0. 25 mm 2mm, respectively. The maximum value of PQ was at 2~0.25mm level. With the increase of straw depth, the carbon content and PQ content of HA,Hu changed from the surface layer to the subsurface layer to the lower surface layer. Straw depth was also beneficial to the accumulation of carbon in HA and Hu, the increase of PQ value, the increase of humic degree and the improvement of humus quality. (4) the carbon content and condensation degree of HA in black soil control soil were higher than those in tidal cinnamon soil, and the oxidation degree was lower than that in tidal cinnamon soil. The HA quality of black soil is better than that of tidal cinnamon soil. The carbon content and oxidation degree of 2~0.25mm in tidal cinnamon soil were the largest and the degree of oxidation was the lowest, whereas 0.053mm particle size was opposite. Compared with the subsurface layer, the average carbon content of HA in black soil and tidal cinnamon soil is higher than that in subsurface layer, and the degree of oxidation is lower than that of subsurface layer, in addition, the condensation degree and thermal stability of black soil are lower than that of subsurface layer. Aliphatic carbon / carboxyl carbon and aliphatic carbon / aromatic carbon were higher than those in subsurface layer. The structure of HA in surface layer was simpler and younger. Straw depth also reduced the oxidation degree of HA in black soil and tidal cinnamon soil, and decreased the condensation degree and thermal stability of black soil. (5) the carbon content, condensation degree and oxidation degree of Hu in black soil were higher than those in corresponding HA, and the degree of oxidation was lower. The straw depth also reduced the oxidation degree and stability of Hu in the surface and subsurface aggregates of black soil, decreased the aliphatic chain hydrocarbons, increased the active structure, and simplified the structure of Hu.
【学位授予单位】：吉林农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S141.4

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