经济植物篱保墒效果灰色分析

GREY ANALYSIS OF THE EFFECT OF SOIL MOISTURE RETENTION OF ALLEY CROPPING

通过对不同坡度坡地种植经济植物篱的田间土层水分运行状态和机制进行研究,借助灰色聚类分析和灰色关联分析,结果表明:在四川盆地丘陵农区,旱坡地上间作经济植物篱具有保水保墒效果,这种效果随坡度增高而加大。例如在坡度为20°时,各类植物篱如紫穗槐、枣、香根草等,都能有效提高土壤水分含量,其保水能力总体上高于同田间作的其他农作物;但在坡度为8°时,各类植物篱如香椿、梨、枇杷等的保水保墒能力则与其他间套作物相当。其原因是随着坡度加大,一方面水土流失增加,使经济植物篱保水保墒效果逐渐凸现,另一方面是耕作位移和耕作侵蚀增加,梯台地形成速度加快,使种植带土层变厚保墒能力增加。通过对灰色聚类分析中传统的三角坐标作图法进行改进,使三角坐标作图方法变得规范科学,可以对系统动态过程进行客观定量形象的描述。

Grey cluster and association analyses of the soil moisture status and mechanism in the soil profile under alley cropping system on different slopes showed that alley cropping enhanced soil moisture holding capacity in the purple hilly areas of Sichuan, with greater positive effect on steeper sloping land. All hedgerows formed by false indigo, Chinese date and vetiver significantly enhanced soil moisture content of sloping land with a slope of 20° as compared with other intercropped plants, while the hedgerows formed by Chinese toon, pear and loquat had about the same soil moisture as the other crops on land with a slope of 8°. It is speculated that two factors are responsible for such results. On the one hand, soil erosion increases with land slope, and the moisture and soil conserving effect of hedgerows becomes more prominent on steeper slopes; on the other, soil movement and erosion caused by cultivation increases the thickness of soil layer near the hedgerows and speeds up the formation of terrace on slope land.