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Acta Prataculturae Sinica ›› 2022, Vol. 31 ›› Issue (3): 92-100.DOI: 10.11686/cyxb2020565

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Effect of mowing in different phenological growth stages on shoot regrowth, root morphology and forage yield of Leymus chinensis

Cheng-zhen ZHAO1,2(), Qiang LI1, Rong-zhen ZHONG1()   

  1. 1.Jilin Provincial Key Laboratory of Grassland Farming,Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences,Changchun 130102,China
    2.University of Chinese Academy of Sciences,Beijing 100049,China
  • Received:2020-12-09 Revised:2021-01-06 Online:2022-03-20 Published:2022-01-15
  • Contact: Rong-zhen ZHONG

Abstract:

Mowing is a common practice in the utilization of Leymus chinensis grassland. In this field experiment a single mowing in late season on August 15 (control treatment, CON) was compared with treatments initially mown at various earlier growth stages, and again on August 15, to explore the effect of mowing at different phenological growth stages on the regrowth and yield of L. chinensis. Mowing treatments were: at elongation stage on May 15 (ES), at heading stage on June 1 (HS) and at flowering stage on June 15 (FS). It was found that the HS and FS treatments increased (P<0.05) the dry matter (DM) yield compared to CON, while the ES treatment decreased yield (P<0.05). All mowing treatments had increased crude protein yield compared to CON. The regrowth processes of L. chinensis differed between the treatments mown at different phenological growth stages. The ES treatment had the lowest fine root length, root surface area, and root volume. The FS treatment had highest net photosynthetic rate of L. chinensis in the later stages of regrowth, but the water soluble carbohydrate (WSC) content in roots was lower (P<0.05) than other treatments. The root morphology and root WSC contents of the HS and CON treatments did not differ significantly. Although the regrowth processes of L. chinensis in various phenological growth stages of mowing were different, the regrowth yields were similar, especially those of ES and HS treatments. This was because that longer regrowth cycle was offset by lower regrowth efficiency. Therefore, the total DM accumulation was mainly determined by the pre-mowing DM yield. In conclusion, initial mowing at heading stage should be adopted to increase the production of L. chinensis and ensure its persistence in grassland in northeast China.

Key words: Leymus chinensis, initial mowing, phenological growth stages, root morphology