木薯花生不同间作模式对木薯地土壤肥力的影响

为探究木薯花生不同间作模式对木薯地土壤肥力的影响，设置1行木薯2行花生(C₁P₂)、2行木薯3行花生(C₂P₃)和2行木薯4行花生(C₂P₄)3种间作模式，以单作木薯(MC)为对照，测定0~20 cm土层pH、有机质、碱解氮、速效磷、速效钾、蔗糖酶、脲酶、酸性磷酸酶、过氧化氢酶、可培养细菌数量、可培养真菌数量11个土壤肥力指标，利用主成分分析法对11个指标的土壤肥力变化率进行综合评价。结果表明：（1）C₂P₄模式的土壤速效磷、速效钾含量和可培养细菌数量显著低于MC处理;C₁P₂模式仅土壤速效磷含量显著低于MC处理;C₂P₃模式的pH、脲酶活性显著高于MC处理，可培养细菌数量显著低于MC处理。（2）由主成分分析3种间作模式的土壤肥力综合得分可知，C₁P₂间作模式能促进木薯地土壤肥力的提高，而C₂P₃和C₂P₄模式使土壤肥力下降。推广C₂P₄模式，应补充因增产而被带走的养分量，维持木薯地的土壤肥力，从而实现可持续发展。

Effects of Cassava-Peanut Intercropping Patterns on Soil Fertility

To explore the effects of different cassava-peanut intercropping patterns on soil fertility, four treatments were set, which were mono-cropping cassava (MC), one row of cassava intercropping with two rows of peanut (C₁P₂), two rows of cassava intercropping with three rows of peanut (C₂P₃) and two rows of cassava intercropping with four of rows peanut (C₂P₄). A total of 11 soil fertility indexes, such as pH, organic matter, alkali-hydrolyzable nitrogen, available phosphorus, available potassium, sucrase, urease, acid phosphatase, catalase, the number of culturable bacteria and the number of culturable fungi, in the 0-20 cm soil were measured, then the change rate of the 11 soil fertility indexes were assessed comprehensively by the principal component analysis (PCA). The results showed that: (1) the content of soil available P, available K and the number of culturable bacteria of C₂P₄ were significantly lower than those of MC, the content of soil available P of C₁P₂ was significantly lower than that of MC, the pH and urease activity of C₂P₃ were significantly higher than those of MC, while the number of culturable bacteria of C₂P₃ was significantly lower than that of MC; (2) according to the PCA scores of the comprehensive soil fertility, C₁P₂ could improve the soil fertility, while C₂P₃ and C₂P₄ could decrease the soil fertility. To promote the C₂P₄ pattern, additional nutrients should be applied to maintain the soil fertility of cassava field for yield increase, thus achieving the sustainable development cassava industry.