Trade-off between nutritive value improvement and crop water use for an alfalfa–grass system

Abstract

Alfalfa (Medicago sativa L.) can enhance the supply of nutritious forage when interseeded into semiarid native grassland. Alfalfa is a high water-using species; therefore, a possible trade-off between soil water depletion and nutritive value merits study. We determined the effects of interseeding three alfalfa cultivars at two densities on crude protein (CP) and digestible organic matter (DOM) accumulations, the water footprint (WF, m3 evapotranspiration kg−1) of CP and DOM accumulation at two row spacings, and the marginal cost (MC) of such trade-offs. Nutritive values and accumulation of CP and DOM for mixtures with alfalfa planted at 36- or 71-cm row spacing did not differ in 2018 (P >.05), as both spacings reduced the WF over grass only (P