典型黑土区坡耕地退化程度诊断与评价

Evaluation of the Degradation Degree of Sloping Cropland in Typical Black Soil Region

为了对黑土区坡耕地退化程度进行全面、综合、客观的诊断与评价,通过文献计量法和频度分析法对国内外耕地退化评价文献内的高频指标进行了统计分析,建立了适用于东北典型黑土区坡耕地退化程度诊断与评价的指标体系(TIS)。同时以拜泉县为研究区域,通过聚类分析建立了土壤退化程度诊断与评价最小指标集(MIS)。结果表明:(1)TIS共包括物理、化学、生物和侵蚀特征因子4类共11项指标:腐殖质层厚度、黏粒含量、有机质含量、pH值、坡度、垄坡角、沟壑密度、容重、水稳性大团聚体含量、土壤阳离子交换量和作物产量,其中前6项指标组成了MIS。(2)研究区未退化土壤占12%,轻度退化土壤占12%,中度及以上退化土壤占76%。坡度可能是影响研究区土壤退化的主要因素之一,坡度与垄坡角之间存在协同关系。此外,施用农药、化肥以及连作导致土壤酸化问题突出。

A comprehensive evaluation indicator system is needed to provide a complete and integrated assessment of the degradation degree of sloping cropland.We employed bibliometrics to perform statistical analysis on research studies involving cropland degradation.Frequency analysis was then used to identify high-frequency indicators to construct a total index set(TIS)for evaluation of the degradation degree of sloping cropland in black soil region.In addition,soil measurement data from sloping cropland in Baiquan County,were used as a basis to construct a minimum index set(MIS).The TIS included the following 11 indexes:A-horizon thickness,clay content,organic matter content,pH value,slope gradient,ridge-slope angle,gully density,bulk density,large water-stable aggregate content,soil cation exchange capacity,and crop yield.The first six of these were included in the MIS.In the studied area,undegraded soil,mildly degraded soil,and moderately degraded soil and above accounted for 12%,12%and 76%of investigated sloping croplands,respectively.Slope gradient is one of the main factors affecting soil degradation,there is a synergistic relationship between slope gradient and ridge-slope angle.In addition,the application of pesticides,fertilizers and continuous cropping resulted in soil acidification.