title: [Changes and influencing factors of the soil organic carbon in farmland in the last 30 years on Hilly Loess Plateau: a case study in Zhuanglang County, Gansu Province].
abstract: By analysing the sampled data and the results of the second national soil survey by the mid 80 s in Zhuanglang County, the article studied on the changes and influencing factors of the soil organic carbon in farmland of this area in the last 30 years. Farmland samples of top soil (0-20 cm) were collected and analyzed in July 2011. The results showed that (1) The average contents of the soil organic carbon in the county's farmlands were 6.80 g x kg(-1) in 1985 and 8.90 g x kg(-1) in 2011. It increased by 30.9% in the past 30 years, which appeared as a carbon sink effect. The area of increasing contents of soil organic carbon accounted for about 90% of the county's farmland area. (2) Under the available management measures and farmland input, the loessal soil organic carbon stability level was 11.0 g x kg(-1), The SOC accumulation rate showed that the farther the SOC was from the stability level the more quickly it changed, and the closer the SOC was from the stability level the slower it changed. (3) The SOC changes was affected by the altitude, the primary content of organic carbon, and the soil types and so on, in which the greatest contribution factor was the altitude, the influence of the primary content of organic carbon, soil type, production and organic fertilizer on soil organic carbon change was smaller, and the slope aspect had the smallest effect on soil organic carbon change.
authors.forename: Chen-Di
authors.initials: CD
authors.lastname: Shi
authors.forename: Ming-Xiang
authors.initials: MX
authors.lastname: Xu
authors.forename: Yu-Jie
authors.initials: YJ
authors.lastname: Qiu
authors.forename: Zhi-Xia
authors.initials: ZX
authors.lastname: Zhang
authors.forename: Xiao-Wei
authors.initials: XW
authors.lastname: Zhang
mesh_terms: D000383:Agriculture; D000531:Altitude; D002244:Carbon / Q000032:analysis*; D057965:Carbon Sequestration; D002681:China; D005308:Fertilizers; D012987:Soil / Q000737:chemistry*
chemical_list: D005308:Fertilizers; D012987:Soil; D002244:Carbon