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Acta Prataculturae Sinica ›› 2023, Vol. 32 ›› Issue (3): 80-90.DOI: 10.11686/cyxb2022279

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Effects of nitrogen application rate on seed yield and nitrogen use efficiency of Elymus

Tong-yao LI1,2(), Qing-ping ZHOU1,2, You-jun CHEN1,2, Yuan ZHAN1,2, Hui WANG1,2()   

  1. 1.Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station,Chengdu 610041,China
    2.Institute of Qinghai-Tibetan Plateau,Southwest Minzu University,Chengdu 610041,China
  • Received:2022-06-28 Revised:2022-08-31 Online:2023-03-20 Published:2022-12-30
  • Contact: Hui WANG

Abstract:

Nitrogen is one of the crucial macroelements contributing to the growth and development of gramineous (poaceous) plants. However, excessive nitrogen application will result in environmental pollution, increased production costs and a decrease in profitability. Based on the strong demand and the low seed yield of Elymus in the Qinghai-Tibet Plateau area, this study investigated the seed yields of two Elymus species under six nitrogen fertilizer application rates. The cultivars investigated were Elymusbreviaristatus cv. Tongdeand Elymus sibiricus cv. Qingmu No. 1. The six nitrogen application treatments in this study were 0, 45, 90, 135, 180 and 225 kg N·ha-1. The effects of nitrogen application on seed production and nitrogen use efficiency of Elymus were analyzed to provide reference data for seed production in Elymus. It was found that nitrogen application promoted the growth of both tested Elymus varieties. Forage vegetative growth was enhanced, including plant height, tillers per unit area, the seed yield and yield components such as fertile tillers per unit area, spikelets per ear, seeds per ear and 1000-seed weight. With increase in nitrogen application rate, the various yield indexes initially increased and then plateaued or decreased. As successive nitrogen increments were added, the agronomic use efficiency of E. sibiricus cv. Qingmu No. 1 initially increased and then decreased, while the agronomic use efficiency and differential N response of both cultivars gradually decreased. In this study, E. breviaristatus cv. Tongde and E. sibiricus cv. Qingmu No. 1 had seed yields of 712-1661 kg·ha-1 and 701-1626 kg·ha-1, respectively. In order to manage and reduce N fertilizer inputs, the recommended N fertilizer application rate was 135-180 kg·ha-1. Correlation analysis and pathway analysis showed that fertile tillers per unit area and seeds per ear contributed more to the increase of seed yield among seed yield components.

Key words: Elymus, nitrogen application, yield components, seed yield, nitrogen utilization rate