漂白湿润淋溶土不同层次养分对红薯产量影响的研究

漂白湿润淋溶土表层的有效钾、全磷、有效磷含量显著高于表下层,其它养分上下两层的含量差异尽管没有达到5%的显著性水平,但都有向表层集中的趋势。主分量分析结果表明,第一主分量是含氮有机质形成过程强度的量度,表层和表下层有机质、全氮、全磷、有效氮、表下层有效磷均对第一主分量有较大的正向负荷量。第二主分量表示含氮有机质形成过程强度大致相同的情况下,各种养分对红薯产量促进作用的量度,其中表层和表下层有效钾,表下层有效磷对第二主分量的负荷量最大,远远超出其它因素的作用。相关分析也表明,三者与红薯产量呈极显著正相关。这间接表明,将钾肥施入表层和表下层均能提高红薯产量,磷肥只有施入表下层才有增产效果,而氮肥目前不表现增产作用。以上结论为肥料三要素组合试验所证实。这意味着在不改变变量属性的前提下,把多个变量按照变量的特性组合成少数新变量用来解决多因素复杂问题的主分量分析方法,能够科学地、合理地指导作物施肥。

Principal Component Analysis for the Influence of Various Nutrients in Albiudic Cambosols Profile on Sweet Potato Yield and Relevant Experiment Facts

The contents of total phosphorus,available phosphorus,and potassium in surface layer are significantly higher than those in subsurface layer for tested albiudic cambosols.The difference of contents of other nutrients between surface and subsurface layers did not reach the significant level of 5%,but they tend to have concentred in the surface layer.The result of principal component analysis shown that the first principal component standed for the intensity of organic matter formation,while the second principal component standed for promotion of sweet potato.Of various nutrients,available potassium in surface layer,available potassium, and phosphorus in subsurface layer have much higher positive loading for the second principal component.And the yield of sweet potato has significantly positive correlation with available potassium in the surface layer,and available potassium,and available phosphorus in the subsurface layer.The findings suggested that application of potassium fertilizer to both surface layer and subsurface layer can promote sweet potato yield,while phosphorus fertilizer has to be applied to subsurface layer of soil in order to achieve higher yield.There fore, traditional practice that fertilizers were applied to surface layer must be changed.It also is suggested that the principal component analysis method is useful for rational application of fertilizers for sweet potato.