Wim Spaan, J. Ringersma, L. Stroosnijder, A. Sikking
Department of Environmental Sciences
Wageningen University
Nieuwe Kanaal 11
6709 PA Wageningen, The Netherlands
Fax: 0031 317484759
E-mail: Wim.Spaan@users.tct.wau.nl

Runoff management is one of the tools to increase the available water for agricultural production in areas where rainfall is erratic. Vegetation barriers have shown to increase the amount of water in the soil by slowing down runoff and thus allowing more time for infiltration. They do not cause upstream water logging problems due to the semi-permeable character of the barrier. However little is known about the water use of the vegetation barrier and thus whether its conservation effect is not being minimized by its own water use. This paper presents the results of a study conducted in Burkina Faso in 1996 in which a method has been developed to assess the water use of a vegetation barrier. Transpiration (sapflow) was measured on 3 barrier species (Andropogon gayanus, Piliostigma reticulatum and Ziziphus mauritiana). Transpiration was related to meteorological factors and soil moisture availability. The method used was found to be simple and reliable. The results can be used in other experiments focusing on the water use of (natural) vegetation and its competition with agricultural crop water use.