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以河北曲周县原状草地土壤和农田土壤为研究对象,结合稳定性碳同位素方法,分析不同秸秆还田方式、耕作方式和施肥水平对土壤有机碳特性的影响.研究表明,华北原状草地改变为农田后(34 a),土壤有机碳显著降低,且因农田栽培方式不同而异,1 m土层降低幅度在13.3%～35%之间,但降低显著发生在0～40 cm.经过8 a施加底肥,可以提高土壤有机碳0.83g.kg-1.免耕方式可以显著提高土壤有机碳,且主要发生在0～10 cm土层.翻耕操作会引起10～15 cm和15～20 cm土层的土壤有机碳高于免耕处理的现象.土壤有机碳的δ13C值的比变化主要发生在0～20 cm土层,玉米种植输入的有机碳主要集中在土壤0～20 cm层次.在土壤0～5 cm表层,源于农作物的土壤有机碳所占的最高比例为18%,到15～20 cm已经降到了5%左右.
The effects of different straw returning methods, tillage patterns and fertilization levels on soil organic C were analyzed based on the stable carbon isotope method using the grassland soil and farmland soil in Quzhou County of Hebei Province as the research object.The results showed that the change of the former grassland in North China to Soil organic carbon decreased significantly after farmland (34 a), and decreased by 13.3% -35% in 1 m soil layer but decreased significantly at 0-40 cm due to different farmland cultivation methods. After 8 years Application of base fertilizer can increase soil organic carbon 0.83g.kg-1. No-tillage mode can significantly increase soil organic carbon, and mainly occurs in 0 ~ 10 cm soil layer. Tillage operation will cause 10 ~ 15 cm and 15 ~ 20 cm Soil organic carbon in soil layer was higher than that in no-tillage treatment.Changes of δ13C value of soil organic carbon mainly occurred in 0 ~ 20 cm soil layer, while input organic carbon in corn planting mainly concentrated in 0 ~ 20 cm soil layer. Soil 0 ~ 5 cm surface layer, the highest proportion of soil organic carbon from crops is 18%, to 15 ~ 20 cm has dropped to about 5%.