Structural root form and flue root distribution of some woody species evaluated for agroforestry systems

Fine root distribution and structural root characteristics of four-years-ol d multipurpose woody species with potential for use in agroforestry systems were investigated on an Alfisol in the forest savanna transition zone of s outh-western Nigeria. Rooting patterns of woody species studied differed co nsiderably. Lonchocarpus sericeus had thr lowest percentage (21%) of total fine roots confined to the upper (0 to 30 cm) soil layer, compared to 84% w ith Tetrapleura tetraptera. Despite the superior tap root system of Enterol obium cyclocarpum and the fine root form of Nauchlea latifolia however, the ir extensive distribution and very large lateral woody root volume density may pose a major problem for seedbed preparation and tillage operations in simultaneous agroforestry systems. Lonchocarpus sericeus appears to have th e most desirable structural and fine root architecture among the species st udied for simultaneous agroforestry systems. The total root density below t he underlying distal soil layers was linearly related to the sum of square of tap root diameter and the corresponding soil depths.