基于土壤特征和土地利用变化的土壤质量评价最小数据集确定

Establishing a minimum dataset for soil quality assessment based on soil properties and land use change

进行土壤质量评价前,必须先从大量土壤理化、生物学参数中严格选取对土壤质量敏感的评价参数最小数据集(MDS)。考虑到目前经济转型期我国剧烈的土地利用变化对各种土壤过程的深刻影响,通过以下3步选取土壤质量评价MDS:通过主成分分析(PCA)计算各土壤参数在所有特征值≥1的主成分上的综合荷载;通过多变量方差分析定量了土地利用变化对各土壤参数的贡献;通过均值多重比较确定了土地利用年限对土壤性质的定量影响。最后经过线性变换、分组、相关分析检验等过程,得到一个能最大限度的代表所有候选土壤参数而又尽可能少的损失这些候选参数所包含的土壤质量信息的最小数据集。该土壤质量评价MDS因子选取方法能很好地整合土地利用变化的综合定量影响,同时具有很好的灵活性、可扩展性并能外推到其它地区。通过将该方法分别应用在1985年及2004年采样分析的两套数据各12个土壤候选参数集上,得到了各包含6个因子的MDS及其在20a尺度上的变化规律,发现MDS因子略有不同,但变化不大。

To assess soil quality, a Minimum Data Set （MDS） of soil properties has to be proposed commonly through calculating the total load of each candidate soil parameters on all of the qualified principal components by the use of Principal Component Analysis （PCA） and Norm-value computation. Considering intensive land-use change, the method introduced in this study for MDS establishment integrated the quantified contribution of landuse forms and duration to each soil parameter using multivariate analysis and mean multiple comparison. In this way, a MDS representing maximally all candidates with minimal loss of the soil quality information contained by those non-MDS soil parameters is established. The MDS p also is sets of roposed can not only well integrate the quantified influence of land-use change and duration on soil parameters, but quite flexible and extendable with the potential to be extrapolated to assess soil quality in other regions. Based on two soil database obtained separately in 1985 and 2004, two MDSs established, were compared with each other. It wasfound only a quite small change in MDS component occurred during a 20-year period. For a better assessment of soil quality, it seemed necessary to examine at what temporal scale and how much the MDS will change for a site-specific areawith intensive landuse change.