Effect of irrigation methods and quota on root water uptake and biomass of alfalfa in the Wulanbuhe sandy region of China

A field study was conducted in the Wulanbuhe sandy region to determine the effect of irrigation methods and quota on root water uptake and biomass of alfalfa (Medicago sativa L.). The results showed that water uptake rate by roots (S(z, t)) was closely related to the soil moisture content. Roots of local alfalfa would extract water mainly from the soil in the upper root zone if water content were appropriate. Otherwise, the peak of S(z, t) would move, usually down, to other places where moisture content was higher. S(z, t) gradually increased with the growth of alfalfa. Different water supply showed significant effects on shoot and root biomass of alfalfa. Insufficient water supply could stimulate development of roots. Compared with flooding irrigation, the sprinkler method resulted in more shoot biomass although the quota was 1/3-1/4 less, therefore, the sprinkler method would be suitable for extending the planting of alfalfa in this region. (C) 2003 Elsevier Science B.V. All rights reserved.