基于因子和聚类分析的保护性耕作土壤质量评价研究

Evaluation of soil quality under conservation tillage via factor and cluster analyses

  • 摘要: 基于长期定位试验, 选择12项反映土壤质量特性的定量因子作为评价指标, 采用因子分析对不同耕作模式的土壤质量进行综合评价, 并运用欧氏距离最短法对其进行聚类分析。12项理化及生物属性指标归纳为5个公因子: 保肥供肥因子、有机质因子、容重因子、磷素因子、酶活性因子。因子得分的结果表明: 不同耕作模式的5个公因子优势差异明显。相比较而言传统耕作的土壤质量综合得分最低, 说明在研究区保护性耕作模式条件下土壤在物理、化学、生物学性质方面都有所改善, 土壤质量有所提高。土壤质量综合得分最高的前3种处理为隔年深松(NS2)、秸秆覆盖联合浅松、旋耕(SR2)、连年深松(NS3), 说明深松、旋耕及秸秆还田与旋耕技术联合作业在改善土壤结构和培肥土壤方面优势更突出。聚类分析结果表明, 同一耕作措施的不同模式土壤质量差异较小, 说明在本研究试验条件下, 耕作措施是影响土壤质量的关键因素。

     

    Abstract: In this study, factor (FA) and cluster (CA) analyses were used to evaluate the effect of the patterns of conservation tillage on soil quality. The squared Euclidean distance method of hierarchical cluster analysis was used for the cluster analysis. Twelve quantitative indicators related to soil property were selected based on results from long-term experimentation. Using factor analysis, five soil common quality factors (i.e., maintenance and supply capacity of soil nutrient, organic matter, phosphorus, bulk density, and enzyme activity) were derived from 12 soil chemical, physical and biological attributes. Factor scores show significant differences in superiority of the five common factors under different tillage patterns. Soil quality scores for conservation tillage (CT) are higher compared with traditional tillage (TT), implying improved soil physical, chemical and biological properties along with soil quality under CT. The top three integrated patterns with the highest scores include 30 cm subsoiling at one-year interval (NS2); combined straw mulching and 20 cm subsoiling, rotary tillage (SR2); and 30 cm subsoiling at yearly interval (NS3). This suggests outstanding advantage of the top integrated patterns in improving soil structure, soil fertility and overall soil quality. CA shows small differences in soil quality among different patterns under one tillage practice, indicating that tillage measurement is the key factor of soil quality.

     

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