title: [Content and evolution characteristics of organic carbon associated with particle-size fractions of grey desert soil under long-term fertilization].
abstract: Physical fractionation technique was used to analyze the content, distribution, and temporal evolution of organic carbon associated with particle-size fractions of grey desert soil under long-term (1990-2007) fertilization. Compared with no fertilization, a combined application of manure and chemical fertilizers increased the organic carbon associated with particle-size fractions significantly, with the highest increment (0.34 g x kg(-1) x a(-1)) in sand. Following also increased the organic carbon associated with clay and silt significantly. Straw return to cropland only maintained the organic carbon content in different particle-size fractions, while long-term application of chemical fertilizers was not beneficial to the organic carbon increase in particle-size fractions. Coarse silt and coarse clay had the highest distribution rates of organic carbon (27.9% and 27.1%, respectively), being the important fractions in sequestrating organic carbon. When manure was applied with chemical fertilizers, the organic carbon in sand was significantly increased by 119.4%, while that in fine silt and coarse clay was significantly decreased by 40.3% and 37.9%, respectively, which resulted in the increase in the ratio of particulate organic carbon content (W(POC)) to mineral-associated organic carbon content (W(MOC)), and improvd soil carbon property. Long-term application of manure combined with chemical fertilizers was the best mode to increase the organic carbon content in particle-size fractions and improve the fertility of grey desert soil.
authors.affiliation: Institute of Soil, Fertilizer and Agricultural Water Saving, Xinjiang Academy of Agricultural Sciences, Urumqi 830000, China. liuhualh@sohu.com
authors.forename: Hua
authors.initials: H
authors.lastname: Liu
authors.forename: Xiao-Gang
authors.initials: XG
authors.lastname: Tong
authors.forename: Xing-Wang
authors.initials: XW
authors.lastname: Ma
authors.forename: Xi-He
authors.initials: XH
authors.lastname: Wang
authors.forename: Wen-Ju
authors.initials: WJ
authors.lastname: Zhang
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Xu
authors.forename: Ming-Gang
authors.initials: MG
authors.lastname: Xu
mesh_terms: D000383:Agriculture / Q000379:methods*; D002244:Carbon / Q000032:analysis*; D003889:Desert Climate; D005308:Fertilizers; D009930:Organic Chemicals / Q000032:analysis; D010316:Particle Size; D012987:Soil / Q000032:analysis*; D013997:Time Factors
chemical_list: D005308:Fertilizers; D009930:Organic Chemicals; D012987:Soil; D002244:Carbon