利用方式对灌淤土团聚体稳定性及有机碳官能团特征的影响

The Influence of Aggregate Stability and Characteristics of SOC Functional Groups in Anthropogenic-alluvial Soil Under Different Land Use Patterns

为深入分析利用方式对农田土壤结构稳定性及有机碳化学性质的影响,采用干筛法、湿筛法等测定旱作和水田2种利用方式下灌淤土团聚体粒级分布,并计算土壤团聚体破坏率,同时应用同步辐射软X射线（XANES）测定其有机碳（SOC）官能团组成及变化特征。结果表明：旱作土壤以〉5mm大粒径团聚体为主（48.19%）,且大于水田土壤（38.16%）,而水田土壤则是微团聚体含量（32.94%）大于旱作（13.51%）;旱作方式土壤大粒径（〉1mm）团聚体破坏率小于水田方式,而小粒径（1-0.25mm）团聚体破坏率大于水田。随着团聚体粒径减小,土壤稳定性SOC官能团（芳香-C和O-烷基-C）相对百分含量减少,活性SOC官能团（羧基-C）相对百分含量增加,且SOC官能团的变化主要体现在粒径〉1mm的团聚体中;旱作方式下土壤活性SOC官能团（羧基-C）相对百分含量高于水田,稳定性SOC官能团（芳香-C、O-烷基-C）小于水田方式。与旱作方式相比,水田方式有利于土壤稳定性SOC官能团的积累,且可提高土壤有机碳化学稳定性和总有机碳含量。

For better analysis the effect of farmland soil structure and the organic carbon chemistry properties on different land use patterns,anthropogenic-alluvial soil aggregate distribution and PAD was studied in upland and paddy using the dry and wet sieving.Furthermore,the composition and changes of soil organic carbon（SOC）functional groups in soil aggregate under different land use patterns was studied by X-ray Absorption Near Edge Structure（XANES）.The results showed that there were mainly large size（〉5mm）aggregate in upland and content was 48.19% more than paddy（38.16%）,while the paddy＇s micro-aggregate content（32.94%）was greater than the upland（13.51%）;large size aggregate destruction rate（〉1 mm）of upland was less than that of paddy,on the contrary,small size aggregate（1-0.25mm）destruction rate was higher than paddy.The relative percentage of stabilized SOC functional groups（fragrance-C and O-alkyl-C）were reduced with aggregate particle size decreasing in upland and paddy,while the relative percentage of active SOC functional groups（carboxyl-C）was increased,and the changes of SOC functional groups were mainly embodied in 〉1mm aggregate;the relative percentage of active SOC functional groups（carboxyl-C）in upland was higher than paddy;the stabilized SOC functional groups（fragrance-C and O-alkyl-C）,however,less than paddy.Since the stabilized SOC functional groups was more advantage to be accumulated in paddy than upland,the stability of soil organic carbon and total organic carbon content was improved in paddy.