玉米/大豆间作条件下的作物根系生长及水分吸收

Crop root growth and water uptake in maize/soybean strip intercropping

通过田间试验研究了玉米/大豆条带间作群体的根系分布及土壤水分吸收规律.结果表明:水分充足条件下,土壤剖面内玉米和大豆根系的分布模式近似于三角形;玉米根系水平分布范围较大,侧向伸展长度约为58cm,16～22cm土层的玉米根系侧向伸展最远,玉米根系不仅分布于间作条带行间,而且生长到大豆条带的行间;大豆根系水平分布于相对有限的区域内,侧向伸展长度约为26cm.作物根质量密度随着距作物行(玉米或大豆)距离的增加而减少,玉米行和边行大豆根质量密度的90%分布于0～30cm土层.距玉米行10cm处玉米的根质量密度高于大豆,距玉米行20cm处大豆的根质量密度大于玉米,两种作物根质量密度的85%都分布于0～30cm土层内.间作条带内水分变化主要集中在0～30cm土层,水分变化量依次为:玉米区域>大豆区域>条带行间.表明在水分充足条件下,间作作物优先在自己的区域吸水,根系混合区吸水滞后发生.

A field experiment was conducted to study the root distribution and water adsorption of maize and soybean in their strip intercropping. The results showed that under the condition of full irrigation, both maize roots and soybean roots were distributed approximately in triangle-shape in soil profile. Maize roots extended horizontally into a wider area, 58 cm away from the plant row and usually occurred in 16-22 cm soil layer. They were not restricted to maize root zone, but traversed into soybean strip zone. Soybean roots were horizontally distributed in a limited zone near the plant row, and their reached range was within about 26 cm. Both for maize and for soybean, their root mass density decreased with increasing distance from the plant row. About 90% of the root mass of maize and edge-row soybean was presented in 0-30 cm soil layer. The root mass density of maize at 10 cm from maize row was greater than that of soybean, but this density of soybean at 20 cm from maize strip was greater than that of maize. About 85% of root mass was distributed in 0-30 cm soil layer, and the variation of soil water content in intercropping strips also occurred mainly in this soil layer. In the maize/soybean strip intercropping system, soil water content decreased in the order of maize zone 〉 soybean zone 〉 middle zone, indicating that each strip-intercropped crop preferentially absorbed the soil water in its strip and utilized the soil water in intermingled zone later.