Planting Density ana irrigation Timing Affects Cleistogenes songorica Seed Yield Sustainability

Native grasses play an important role in the sustainable development of grassland animal husbandry, land protection, and the lawn industry. However, with seed yields often low and variable, it is necessary to develop techniques for increasing seed production in these species. From 2007 to 2012, field trials using nine planting densities (5, 10, 15, 20, 25, 30, 35, 40, and 50 plants m(-2)) were conducted in an arid region of China. The effect of planting density on seed yield and its components was investigated for a drought-tolerant grass species, Cleistogenes songorica (Roshev.) Ohwi. Seed yield persistence and yield response to seasonal rainfall during the trials were also examined. The highest seed yield was obtained at 30 plants m-2, with a mean seed yield of 500 kg ha(-1) over the 6 yr. Among seed yield components, the number of fertile tillers m-2 had the greatest influence on seed yield. The percentage factual seed yield vs. potential seed yield was 40 to 47%. There was a positive correlation between seed yield and precipitation during heading and flowering stages. The present study showed that C. songorica can be used in seed production for at least six consecutive harvests. Irrigation during the heading and flowering stages may be used to increase the seed yield of C. songorica.