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草业学报 ›› 2021, Vol. 30 ›› Issue (3): 41-53.DOI: 10.11686/cyxb2020415

• 研究论文 • 上一篇    下一篇

川西北高原3种禾本科牧草根系特征比较研究

刘斯莉1(), 王长庭1(), 张昌兵2, 胡雷1, 唐立涛1, 潘攀1   

  1. 1.西南民族大学青藏高原研究院,四川 成都 610041
    2.四川省草原科学研究院,四川 成都 611731
  • 收稿日期:2020-09-14 修回日期:2020-11-19 出版日期:2021-03-20 发布日期:2021-03-09
  • 通讯作者: 王长庭
  • 作者简介:Corresponding author. E-mail: wangct@swun.edu.cn
    刘斯莉(1996-),女,四川仪陇人,在读硕士。E-mail: 942932605@qq.com
  • 基金资助:
    国家重点研发计划(2019YFC0507701);第二次青藏高原综合科学考察研究项目(2019QZKK0302);国家自然科学基金(31870407);中央高校基本科研业务费专项资金重点项目(2020NZD03);西南民族大学研究生“创新型科研项目”重点项目(CX2019SZ93)

A comparative study of root characteristics of three gramineous herbage species in the Northwest Sichuan Plateau

Si-li LIU1(), Chang-ting WANG1(), Chang-bing ZHANG2, Lei HU1, Li-tao TANG1, Pan PAN1   

  1. 1.Institute of Qinghai-Tibetan Plateau,Southwest Minzu University,Chengdu 610041,China
    2.Sichuan Academy of Grassland Sciences,Chengdu 611731,China
  • Received:2020-09-14 Revised:2020-11-19 Online:2021-03-20 Published:2021-03-09
  • Contact: Chang-ting WANG

摘要:

探究3种栽培牧草根系特征的差异,对维系川西北退化高寒草地地下生态系统结构和功能意义重大。本研究采用微根管原位监测与室内分析相结合的方法对紫羊茅、垂穂披碱草及老芒麦单播人工草地的根系特征及其土壤环境进行比较分析。结果表明:1)3种栽培牧草根系生长存在明显的季节节律,5-7月为生长高峰期,7-8月为现存高峰期,8-9月为死亡高峰期。2)3种栽培牧草根系现存量均随土层显著降低,其中老芒麦的根系现存量显著高于紫羊茅和垂穂披碱草(P<0.05);紫羊茅根系生产量和死亡量最高,根系净生长速率最低。3)紫羊茅的根系周转率显著高于老芒麦和垂穂披碱草,且随土层加深而显著增加(P<0.05)。4)结构方程模型(SEM)显示,牧草种类和土层深度不仅直接影响根系特征,而且通过改变土壤化学计量比和土壤理化性质,间接影响根尖数和根系动态特征,进而影响根系周转。综上所述,3种栽培牧草在根系生长与资源获取方面存在明显差异性。紫羊茅采取缩短根系寿命,加快根系周转的生长策略以保证营养吸收效率,而垂穂披碱草和老芒麦采取增加根系产量,以及延长根系寿命的策略减缓根系周转,并通过降低根系的碳消耗而增加了其碳汇功能以适应高寒环境。

关键词: 人工草地, 草地恢复, 根系特征, 土壤理化性质, 微根管法

Abstract:

In order to restore degraded alpine grassland in the Northwest Sichuan to sustainability, it is essential to have an understanding of the structure and function of the underground ecosystem and knowledge of the root characteristics of three cultivated herbage species. This study investigated the root characteristics and soil environment of cultivated herbage of Festuca rubraElymus nutans and Elymus sibiricus, using minirhizotron in situ monitoring technology and laboratory experiments. The results showed that: 1) There were obvious seasonal rhythms in the root growth of the three cultivated herbage species. The growth peak was from May to July, the peak of root standing crop was from July to August, and the death peak was from August to September. 2) The root standing crop of the three cultivated herbage species decreased significantly with soil depth (P<0.05). E. sibiricus had significantly higher root standing crop than F. rubra and E. nutans P<0.05); the root production and mortality of F. rubra were the highest, and it’s root net growth rate was the lowest. 3) The root turnover of F. rubra was significantly higher than that of E. sibiricus and E. nutans, and turnover of F. rubra increased significantly with soil depth (P<0.05). 4) Structural equation modeling revealed that herbage species and soil depth not only directly affected root characteristics, but also had indirect effects on root tips and root dynamic characteristics by changing soil stoichiometric ratios and soil physicochemical properties, thus affecting root turnover. In conclusion, there were significant differences in root growth and resource acquisition among the three cultivated herbage species. The strategy of shortening root longevity and accelerating root turnover was used by F. rubra to ensure nutrient absorption efficiency, while E. sibiricus and E. nutans used the strategy of increasing root production and prolonging root longevity to slow down root turnover, and thereby reduced carbon consumption of the root system while simultaneously increasing carbon sink function so as to adapt to the alpine environment.

Key words: artificial grassland, grassland restoration, root characteristics, soil physicochemical properties, minirhizotron