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以7年不同耕作的定位试验为研究对象,研究了深松、旋耕、免耕等保护性耕作对关中塿土小麦-玉米轮作条件下土壤结构体分布以及结构体中有机碳和全氮含量、储量的影响。结果表明,与传统耕作相比,深松、旋耕、免耕以及秸秆还田+传统耕作均提高了>5 mm粒级结构体的含量。随着土壤结构体粒径的增大,结构体有机碳含量逐渐减小,有机碳含量在<0.25 mm结构体中平均含量为10.87 g/kg,在>5 mm结构体中平均含量为9.57 g/kg。在>0.25 mm的各粒级结构体中,全氮含量也随着结构体粒径的增加而减小。深松和旋耕处理较免耕和传统耕作更有利于结构体中有机碳、氮含量的增加;深松和旋耕比较,深松更有利于<2 mm结构体碳氮含量的增加。相关分析表明,土壤碳氮含量和较小粒级(<2 mm)结构体的碳氮含量之间的相关性最好。从有利于结构体保持和有机碳、氮储量增加的角度考虑,深松和旋耕是当地较理想的耕作方式。
Taking seven years of different tillage locating experiments as the research object, this paper studied the distribution of soil structure and the contents of soil organic carbon and total nitrogen in Guanzhong clay soil under the circumstance of conservation tillage, rotary tillage and no tillage. , The impact of reserves. The results showed that compared with the traditional tillage, subsoiling, rotary tillage, no-tillage and straw returning + conventional tillage increased the content of> 5 mm granular structure. With the increase of particle size of soil structure, the content of organic carbon in the structure gradually decreased. The average content of organic carbon in the structure <0.25 mm was 10.87 g / kg and that in> 5 mm structure was 9.57 g / kg. In each size fraction> 0.25 mm, the total nitrogen content also decreases with the increase of the size of the structure. Subsoiling and rotary tillage treatments are more conducive to the increase of organic carbon and nitrogen in the structure than the no-tillage and conventional tillage. Compared with the subsoiling and rotary tillage, subsoiling is more conducive to the increase of carbon and nitrogen content in the <2 mm structure. Correlation analysis showed that the correlation between soil carbon and nitrogen content and carbon and nitrogen content of the smaller size (<2 mm) structure was the best. From the point of view of favoring the maintenance of structures and increasing of organic carbon and nitrogen reserves, subsoiling and rotary tillage are the ideal farming methods in this area.