A classification of East African rangeland. 2. The water balance as a guide to site potential.
An annual index of water availability, expressing the amount of mean total precipitation available for transpiration by plants as a percentage of the annual total of Penman potential evaporation from an open water surface, is defined, and mapped for Kenya using isolines at 10% intervals, making allowance for the water storage capacity of the rooting zone. The relationship between available water index and the ecological zones defined in H.A. 37: 800 is assessed.-R.B.