摘要
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。
Soil organic carbon sequestration is concerned intensively at present in the world because of increase in greenhouse gas emission.Although organic carbon content in natural soil was mainly controlled by climate and vegetation,tillage is considered to be an important factor to affect soil organic content in cropland besides fertilization.In this paper,a seven years＇location experiment in the condition of wheat-corn rotation of Lou soil in Guanzhong Plain was conducted.The effects of different tillage measures such as sub-soiling,rotary tillage and no-tillage on the distributions of aggregates,and the content of organic carbon and total nitrogen in soil aggregates were studied.The results showed that with the increase of soil aggregates sizes,the content of soil aggregates decreased firstly and then increased.Among all the soil aggregates under different tillage treatments,the content was the highest in 5 mm fractions of aggregates and the lowest in 0.5-0.25 mm soil aggregates.The 5 mm size fraction occupied 62.3%-70.2% of the total soil aggregates and 0.5-0.25 mm size fraction occupied 1.10%-1.80%.Compared to the conventional tillage,sub-soiling,rotary tillage and no-tillage all increased the content of 5 mm aggregates.With the increase of aggregates sizes,the content of organic carbon and total N in aggregates decreased.The organic carbon content averaged 10.87 g/kg in the 0.25 mm fraction,being the highest among all soil aggregates.In 5 mm soil aggregates,the content of soil organic carbon was 9.57 g/kg,being the lowest.Sub-soiling and rotary tillage increased the content of organic carbon and total nitrogen in soil aggregates more significantly than that of conventional tillage and no-tillage.The comparison between sub-soiling and rotary tillage showed that sub-soiling mainly increased the content of organic carbon and total nitrogen in 2 mm soil aggregates,but rotary tillage mainly increased them in 2 mm soil aggregates.The effects of conservational tillage on the storage of organic carbon in soil aggregates were more significant than that on the storage of total nitrogen.The Correlation analysis demonstrated that organic carbon in total soil was significantly correlated with organic carbon in 2 mm soil aggregates.The correlation of organic carbon in all 2 mm soil aggregates was significant.Total nitrogen in soil was significantly or very significantly correlated with total nitrogen in all sized soil aggregates except for 0.5-0.25 mm fraction.The correlation of total nitrogen in all sized soil aggregates was very significant to each other.Considering to form and preserve the soil aggregates and increase the storage of organic carbon and nitrogen in soil aggregates,sub-soiling and rotary tillage are the ideal tillage measures in Guanzhong Plain.
出处
《自然资源学报》
CSSCI
CSCD
北大核心
2010年第3期386-395,共10页
Journal of Natural Resources
基金
国家科技支撑项目(2007BAD89B16)
中国科学院知识创新工程重大项目(KSCX1-YW-07)
关键词
土壤结构
有机碳
全氮
保护性耕作
soil structure
organic carbon
nitrogen
conservational tillage
