Physiological reactions to imposed water deficit by Andropogon gayanus cv. Bisquamulatus and Cenchrus ciliaris cv. Biloela in a mixed fodder crop

Guinea grass (Andropogon gayanus Kunth cv. Bisquamulatus) and Buffel grass (Cenchrus ciliaris L. cv. Biloela) are grown as temporary fodder crops in the Sahelo-Sudanese region of Africa. Differences in their responses to drought conditions may be important in optimizing cattle feeding programmes in integrated farming systems. An experiment conducted in a wind tunnel equipped with a tank forming a weighable lysimeter compared net photosynthesis (A), stomatal conductance (gs) and leaf water potential (Ψ leaf) of both species in a mixed sward during three simulated environmental conditions: (1) rainy season, (2) drought period within the rainy season and (3) dry season. With a soil water reserve (SWR in % volume) of 8% during the drought period and the dry season, the Ψ leaf and A parameters were significantly lower (P