免耕秸秆覆盖对土壤活性有机碳库的影响

为探索免耕秸秆覆盖对土壤有机碳库的影响,通过定位试验研究内蒙古武川县旱作免耕覆盖耕作模式下农田不同形态碳素含量、碳素有效率及碳库管理指数变化。结果表明,免耕秸秆覆盖处理比传统耕作显著提高土壤总有机碳、可溶性碳、微生物量碳及易氧化碳的含量及土壤碳库各项指数,且免耕同一留茬高度不同覆盖量处理间各项指标值差异显著,随秸秆覆盖量的增加各项指标值也增加。土壤易氧化碳与碳素有效率A、B、C及土壤碳库管理指数均呈极显著正相关关系,与土壤碳库管理指数的相关系数达0.991,易氧化碳作为土壤活性碳的指标可以更灵敏更直接地反映土壤有机碳短期的变化状况,免耕秸秆覆盖对于提高土壤有机碳库中各项指标值的贡献大于传统耕作。

Effect of Zero Tillage with Mulching on Active Soil Organic Carbon

To explore the effect of zero tillage with mulching on soil organic carbon pool, changes of different types of carbon content , carbon efficiency and carbon pool management index were observed by positioning experiment of zero tillage with mulching on dry land in Wuchuan county of Inner Mongolia. The results showed that mass fraction of soil total organic carbon, dissolved organic carbon, microbial biomass carbon and readily oxidation carbon and indexes of soil carbon pool were improved significantly with straw mulching in zero tillage field compared with conventional tillage. The values of these indexes with the same stubble height but different amount of straws showed big differences in zero tillage field, with the increasing of straw mulching amount these values were also increased. There was the biggest correlation coefficient among readily oxidation carbon and soil carbon efficient A, B,C and soil carbon pool management index, and the correlation coefficient between readily oxidation carbon and soil carbon pool reached as high as 0.991, and it can be concluded that readily oxidation carbon as the index of soil organic carbon can sensitively and directly indicate the changes of soil organic carbon in the short-term . In all, the effect of zero tillage with mulching is better than conventional tillage to improve values of soil organic carbon pool.