The effect of nitrogen addition on seed yield and yield components of Leymus chinensis in Songnen Plain, China

Nitrogen (N) addition strongly influences community composition and ecosystem functioning. However, little is known about their effects on seeds yield attributes of Leymus chinensis (Trin.) Tzvel. in Songnen Plain, China. A field experiment was evaluated in Songnen Plain to investigate the effects of N addition on seeds yield and yield components of L. chinensis. The experiment consisted of five N addition levels (0, 2.9, 5.9, 9.0, 11.9 g N m(2) yr(-1)) was conducted for two consecutive growing seasons. The results showed that, except spikelet number, the other plant characteristic, such as plant height, leaf area, seed setting rate, 1000-grain weight, and seeds yield, were significantly influenced by N addition in the both growing seasons. With increasing N addition, the reproductive seed setting rate, grains number and weight can improve the seed yield in growing season and heading year. Although N addition has the more significantly effect on the seeds yield and yield components (besides spikelet number) in later fall, raised N addition in topdressing did not cause a standing increase trend. Therefore, from our results, the optimal N addition of application 5.90 g m(-2) with a method of topdressing in late fall were recommended to improve the seed yield and yield components of L. chinensis in Songnen Plain, China.