Xu Peng, Jiang Chang-Sheng, Hao Qing-Ju, Zhu Tao
Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of education, College of Resources and Environment, Southwest University, Chongqing 400715, China.
Huan Jing Ke Xue. 2013 Oct;34(10):4009-16.
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.
本研究探讨了不同土地利用方式对土壤有机质（SOM）、土壤活性有机质（SLOM）及其效率比（ER）以及土壤碳管理指数（CMI）的影响。选取亚热带常绿阔叶林（简称：森林）、坡耕地、果园和荒地作为研究对象，于2011年春季采集了0 - 10、10 - 20、20 - 30、30 - 40、40 - 50和50 - 60 cm深度的土壤样本，以测定土壤有机质和活性有机质的含量。结果表明，在四种土地利用类型下，土壤有机质和土壤活性有机质含量均随土壤深度增加而降低；然而，森林和果园分别在0 - 10 cm和0 - 20 cm土层中富集了SOM和SLOM含量，而坡耕地和荒地中SOM和SLOM含量则均匀下降。在整个土壤层（0 - 60 cm）中，SOM和SLOM含量顺序为荒地＞森林＞果园＞坡耕地，这表明从森林转变为果园或坡耕地时，SOM分别减少了21.56%（P＞0.05）和55.90%（P＜0.05），从坡耕地转变为荒地时，低活性SLOM、中活性SLOM和高活性SLOM分别增加了144.2%（P＜0.05）、153.3%（P＜0.05）和242.7%（P＜0.05）。方差分析表明，四种土地利用方式下低ER、中ER和高ER之间无显著差异，这表明SRs对土地利用变化不敏感。所有三种CMIs的顺序均为荒地＞森林＞果园＞坡耕地，这表明毁林开垦导致土壤有机碳储量减少和土壤质量下降，而坡耕地撂荒则会增加土壤碳汇并改善土壤质量。三种SLOM均与土壤全氮、有效磷和有效钾呈正相关，与土壤容重呈负相关，这表明SLOM与土壤理化性质密切相关，可作为反映土壤养分状况和判断土壤质量的重要指标。
