梯田埂坎植物根系营养空间及伸展模式初步研究

 采用三维坐标挖掘法对宁夏南部山区梯田埂坎上较为常见的几种植物根系分布进行了调查,并对根系的伸展模式进行了分类。结果表明:红柳、苜蓿、柠条的根系分布较深,表现出垂直根型的特点;杞柳、杨树表现出了较强的趋水肥的特点;几种植物都表现出不同程度的生态可塑性。阳坡密植的红柳、靠近埂坎下部栽植的柠条、苜蓿、树龄5年以下的杞柳、大地埂中部的杨树根系伸展模式比较符合农林复合系统的要求。建议红柳采用密植的方法栽植于阳坡,阴坡栽植杞柳,但随树龄的变化应适当调整株距;杨树不宜作为埂坎造林的树种,适当发展苜蓿。

Primary Study on Root System Foraging Space and Rooting Pattern of Plants on the Terrace Embankments

Several plant root systems are probed using method of 3D excavation. Based on that, rooting patterns of plants on the terrace embankments are classified. The results indicate that root systems of Tamarix ramosissima Ldb. , Caragana microphylla (pall) lam. and Medicago sativa distribute in deeper soil layers and take on the characteristics of vertical root, root systems of Salix purpurea L. and poplar have a strong tendency toward water and nutrients. All plants investigated are of ecological plasticity of different degree. Rooting patterns of Tamarix ramosissima Ldb. at 1 m distance on the southward slope, Caragana microphylla (pall) lam planted at lower position of the embankments, Medicago sativa, poplar on the middle of big embankments and Salix purpurea L. less than 5 years old are suitable to agroforestry systems. It is suggested that Tamarix ramosissima Ldb. should be planted at short distance (1 m) on the southward slope, Salix purpurea L. on the northward slope, but with ageing, the distance should be adjusted. Poplar is not a suitable tree species to be grown on the embankments. Medicago sativa should be grown on big embankments where there is better conditions of soil moisture, illumination and nutrients.