Abstract
Development of rooting zone formed by a corn plant, which was grown nearly in isolation, was studied. Length of the root in the soil around the plant was determined by means of a personal computer assisted measuring system. On the soil profile, a zone of high root density (>5000 m/m3) extended horizontally from the base of the plant and was rectangular in shape at the beginning of growth. From 10 to 16 weeks after sowing this zone extended downwards. In the region of 0.3 m in depth and 0.3 m from the plant axis, root length density increased very slowly and remained comparatively low until 16 weeks after sowing. Judging from the mean root diameter (mm), thick roots seemed to be grown predominantly under the plant and thin roots in the top soil layer. Total root length increased linearly throughout the growth and was calculated to be up to 157 km, though some reduction of root was observed in 0.01 m soil layer at the end of growth.
