title: [Effects of the different land use on soil labile organic matter and carbon management index in Junyun Mountain].
abstract: The impacts of different land use on soil organic matter (SOM), soil labile organic matter (SLOM) and their efficiency ratios (ER), and soil carbon management index (CMI) were studied in this study. Subtropical evergreen broad-leaved forest (abbreviation: forest) , sloping farmland, orchard and abandoned land were selected and soils at the depths of 0-10, 10-20, 20-30, 30-40, 40-50 and 50-60 cm were sampled in the spring of 2011 to determine the contents of soil organic matter and labile organic matter. The results showed that the contents of soil organic matter and soil labile organic matter both decreased with the increase of soil depth under all four land use types; however, forest and orchard enriched SOM and SLOM contents in the 0-10 cm and 0-20 cm soil layers, respectively, while the contents of SOM and SLOM decreased evenly in sloping farmland and abandoned land. In the whole soil layer (0-60 cm) , the order of SOM and SLOM contents was abandoned land > forest > orchard > sloping farmland, indicating that at the conversion from forest into orchard or sloping farmland, SOM was reduced by 21.56% (P >0.05) and 55.90% (P <0.05), respectively, and at the conversion from sloping farmland into abandoned land, the low SLOM, middle SLOM and high SLOM increased by 144.2% (P<0.05) , 153.3% (P <0.05) and 242.7% (P <0.05), respectively. There was no significant difference in low ER, middle ER and high ER among the four land uses as suggested by ANOVA which showed that SRs were not sensible to the change of land use. All three CMis were in the order of abandoned land > forest > orchard > sloping farmland, revealing that forest reclamation resulted in the reduction of soil organic carbon storage and the decline of soil quality, and the abandonment of sloping farmland would increase soil carbon sink and improve soil quality. Three kinds of SLOM were all positively correlated with soil total nitrogen, available phosphorus and available potassium, while negatively correlated with soil density bulk, indicating that SLOM had close relationships with soil physical and chemical characters and could be used as an important index to reflect soil nutrient status and judge soil quality.
authors.affiliation: Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of education, College of Resources and Environment, Southwest University, Chongqing 400715, China. 836289912@qq.com
authors.forename: Peng
authors.initials: P
authors.lastname: Xu
authors.affiliation: Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of education, College of Resources and Environment, Southwest University, Chongqing 400715, China.
authors.forename: Chang-Sheng
authors.initials: CS
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of education, College of Resources and Environment, Southwest University, Chongqing 400715, China.
authors.forename: Qing-Ju
authors.initials: QJ
authors.lastname: Hao
authors.affiliation: Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of education, College of Resources and Environment, Southwest University, Chongqing 400715, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhu
mesh_terms: D000383:Agriculture; D002244:Carbon / Q000737:chemistry*; D002681:China; D065928:Forests; D009584:Nitrogen / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry; D012987:Soil / Q000737:chemistry*; D014197:Trees
chemical_list: D009930:Organic Chemicals; D012987:Soil; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen