西南“旱三熟”区不同作物和秸秆覆盖对土壤团聚体及固碳潜力的影响

发布时间：2018-05-12 03:16

本文选题：“旱三熟” + 秸秆覆盖　；参考：《草业学报》2016年01期

【摘要】：为了探讨西南"旱三熟"(小麦/玉米/大豆)套作种植模式下农田土壤团聚体的分布特征及有机碳含量变化情况,进而估算该模式下的土壤固碳潜力,在重庆北碚西南大学试验农场对传统耕作(traditional tillage,T)和传统耕作+秸秆覆盖(traditional tillage+straw mulching,TS)2种处理下的土壤团聚体进行筛分和测定。结果表明,3种作物种植下的2mm粒径与2~0.25mm粒径团聚体含量此消彼长,存在显著的负相关关系(r=-0.985,P0.05)。土壤团聚体结构对不同作物的响应不同,水稳性大团聚体(0.25mm粒径)含量在小麦和大豆种植后高达90%左右,玉米种植后约为80%,说明种植玉米有利于土壤水稳性微团聚体的形成。2~0.25mm粒径团聚体的有机碳含量最高,而水稳性微团聚体的两个粒径团聚体有机碳含量相差不大,有机碳含量在团聚体中的分布规律不受种植作物和耕作方式的影响。秸秆覆盖显著提高了0~5cm和5~10cm土层的本土及各个粒径中的有机碳含量,且5~10cm土层团聚体有机碳受秸秆覆盖的影响较大。通过估算固碳潜力发现,玉米条带的土壤固碳潜力显著大于小麦-大豆条带,在耕作处理保持一致的情况下,土壤团聚体有机碳含量对农作物的响应不同。因此,在西南"旱三熟"地区,农田土壤团聚体分布特征和不同粒径有机碳含量受到耕作措施和种植作物的双重影响,土壤固碳潜力主要由水稳性大团聚体的固碳能力决定,水稳性大团聚体更易受到耕作措施和种植作物的影响,在实践中通过秸秆还田提高土壤固碳外,合理安排农作物也有助于提高土壤的固碳能力。
[Abstract]:In order to study the distribution characteristics of soil aggregates and the change of organic carbon content under the "dry triple cropping" (wheat / corn / soybean) intercropping model in southwest China, the potential of soil carbon sequestration under this model was estimated. The soil aggregates under traditional tillage and traditional tillage straw mulching were screened and determined in the experimental farm of Southwest University of Beibei, Chongqing. The results showed that the particle size of 2mm and the content of 2~0.25mm aggregates decreased one by one under the cultivation of three crops, and there was a significant negative correlation between r-0.985 and P0.05. The response of soil aggregate structure to different crops was different. The content of water stable large aggregate (0.25mm) was about 90% after wheat and soybean planting. The content of organic carbon of soil water-stable microaggregate was the highest in 0.25mm diameter aggregate, but the difference between two aggregates was not significant, which indicated that the content of organic carbon of soil water-stable micro-aggregate was about 80% after planting, which indicated that the content of organic carbon of 0.25mm diameter aggregates was the highest, but the difference of organic carbon content between two aggregates was not significant. The distribution of organic carbon in aggregates is not affected by crops and tillage methods. Straw mulch significantly increased the content of organic carbon in 0~5cm and 5~10cm soil layers and the content of organic carbon in soil aggregates of 5~10cm soil layer was greatly affected by straw mulching. By estimating the carbon sequestration potential, it was found that the soil carbon sequestration potential of maize strip was significantly higher than that of wheat-soybean strip, and the response of soil aggregate organic carbon content to crops was different under the condition of consistent tillage treatment. Therefore, in the "dry third cropping" area of southwest China, the distribution characteristics of soil aggregates and the content of organic carbon with different particle sizes are affected by cultivation measures and crop cultivation, and the potential of soil carbon sequestration is mainly determined by the carbon sequestration capacity of water-stable large aggregates. Water stable aggregates are more susceptible to the effects of tillage measures and crop planting. In practice, the soil carbon sequestration can be improved by returning straw to the field, and the rational arrangement of crops will also help to improve the carbon sequestration capacity of the soil.
【作者单位】：西南大学农学与生物科技学院三峡库区生态环境教育部重点实验室南方山地农业教育部工程研究中心;
【基金】：国家自然科学基金(31271673) 公益性行业(农业)科研专项(201503127)资助
【分类号】：S152

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