Effect of Irrigation Schemes on Forage Yield, Water Use Efficiency, and Nutrients in Artificial Grassland under Arid Conditions

Artificial grasslands are effective solutions to problems with grassland degradation. Water scarcity is an important limitation for grassland production in arid regions. In this study, we carried out comparison experiments to assess the impacts of irrigation schemes on forage yield, water use efficiency, and nutrients in the single and mixed sowing ways of Medicago sativa L. and Agropyron cristatum in different stages in artificial grassland. Results indicated that deficit irrigation can increase forage yields of M. sativa and A. cristatum in most growth stages and sowing treatments. Heavy deficit irrigation or even no irrigation had the greatest potential to increase forage yields of both species in the squaring stage and instantaneous water-use efficiency (WUEI) in all growth stages. They can also significantly increase the nutritional level of M. sativa using a mixed sowing method. In June and September, only irrigating to near field capacity (T1) can increase the long-term water-use efficiency (WUEL) of both species. We suggest irrigating with water to near field capacity in June, and applying deficit irrigation in July and August. Deficit irrigation is an effective water management technique to both save water and increase forage quality in arid areas.