Effects of Irrigation and Nitrogen Fertilization on Seed Yield, Yield Components, and Water Use Efficiency of Cleistogenes songorica

Irrigation and nitrogen (N) are two crucial factors affecting perennial grass seed production. To investigate the effects of irrigation N rate on yield (SY), components, water use efficiency (WUE) Cleistogenes songorica (Roshevitz) Ohwi, an ecologically significant grass, a four-year (2016–2019) field trial was conducted in arid region northwestern China. Two regimes (I1 treatment: at tillering stage; I2 tillering, spikelet initiation, early flowering stages) four rates (0, 60, 120, 180 kg ha−1) were arranged. Increasing amounts both improved SY, evapotranspiration, WUE, related components like fertile tillers m−2 (FTSM) seeds spikelet−1. Meanwhile, no difference observed between 120 ha−1 treatments for most variables. The highest SY WUE obtained with treatment combination plus average values 507.3 1.8 mm−1, respectively. Path coefficient contribution analysis indicated that FTSM important component direct path 0.626 0.592. Overall, we recommend (three irrigations) together to increase especially regions. Future agronomic managements breeding programs should mainly focus FTSM. This study will enable producers, plant breeders, government program directors more effectively target higher C. songorica.