Root Growth and Water Uptake by Maize Plants in Drying Soil

Sharp, R. E and Da vies, W. J. 1985. Root growth and water uptake by maize plants in drying soil.— J. exp. Bot. 36: 1441-1456. The influence of soil drying on maize (Zea mays L.) root distribution and use of soil water was examined using plants growing in the greenhouse in soil columns. The roots of plants which were watered well throughout the 18 d experimental period penetrated the soil profile to a depth of 60 cm while the greatest percentage of total root length was between 20-40 cm. High soil water depletion rates corresponded with these high root densities. Withholding water greatly restricted root proliferation in the upper part of the profile, but resulted in deeper penetration and higher soil water depletion rates at depth, compared with the well watered columns. The deep roots of the unwatered plants exhibited very high soil water depletion rates per unit root length. Key words—Maize, roots, water deficit, soil water depletion. Correspondence to. Department of Biological Sciences, University of Lancaster, Bailrigg, Lancaster LAI 4YQ, U.K.