assessing different soil water contents on corn root development

abstract plant roots absorb water and minerals from soil solution. plant production is a function of root distribution and its activity in soil. by increasing root density in soil unit volume, roots absorb more water and minerals. this implies that knowledge of root development is an important factor for crop production. to determine the most suitable amount of water for the maximum development of corn (zea mays l.) root, a greenhouse experiment was conducted in 2006-07. water was applied in 55, 70, 85, 100 and 110 percent of water demand. the total corn roots were taken from the all pots in three stages: i.e. 8-9 leaves, the silk production and the dough. wet and dry weights, volume, surface area and length of roots were measured in all three stages. in addition, ratio of root by dry matter of stem was calculated. the results revealed that weight, volume, surface area and length of roots were increased by increasing in the amount of water applied up to 100% water demand. a significant difference (5%) was found between treatments 85, 100, and 110% water demand with treatment 55% water demand, by an increase in the amount of water applied, the ratio of root to stem was decreased. it means, when water use is in optimum level, the root growth is stimulated, otherwise it is limited. it is concluded that optimum efficiency of water is taken with using 70 percent of water demand instead of 100 or 110 percent.