欢迎访问《草业学报》官方网站,今天是 分享到:

草业学报 ›› 2021, Vol. 30 ›› Issue (8): 73-85.DOI: 10.11686/cyxb2021037

• 研究论文 • 上一篇    下一篇

根系分隔方式下紫花苜蓿/燕麦间作氮素利用及种间互馈特征研究

汪雪(), 刘晓静(), 赵雅姣, 王静   

  1. 甘肃农业大学草业学院,草业生态系统教育部重点实验室,甘肃省草业工程实验室,中-美草地畜牧业可持续发展研究中心,甘肃 兰州 730070
  • 收稿日期:2021-01-26 修回日期:2021-03-08 出版日期:2021-07-09 发布日期:2021-07-09
  • 通讯作者: 刘晓静
  • 作者简介:Corresponding author. E-mail: liuxj@gsau.edu.cn
    汪雪(1997-),女,甘肃定西人,在读硕士。E-mail: 1512339114@qq.com
  • 基金资助:
    甘肃省重点研发计划项目(20YF8NA130);甘肃省重大科技专项(课题3)(19ZD2NA002-3);甘肃省草原技术推广总站项目(XMXZGSNDXY201802)

Nitrogen utilization and interspecific feedback characteristics of intercropped alfalfa/oat with different root barriers

Xue WANG(), Xiao-jing LIU(), Ya-jiao ZHAO, Jing WANG   

  1. College of Pratacultural Science,Gansu Agricultural University,Key Laboratory of Pratacultural Ecosystem,Ministry of Education,Pratacultural Engineering Laboratory of Gansu Province,Sino-US Center for Grazingland Ecosystem Sustainability,Lanzhou 730070,China
  • Received:2021-01-26 Revised:2021-03-08 Online:2021-07-09 Published:2021-07-09
  • Contact: Xiao-jing LIU

摘要:

为探明紫花苜蓿/燕麦间作下种间氮营养竞争和互馈,试验采用桶栽土培法对紫花苜蓿和燕麦进行模拟间作,通过不同生育期、不同氮素水平及不同根系分隔方式对紫花苜蓿和燕麦的氮代谢特性、根系特性及紫花苜蓿结瘤特性进行研究。结果表明:燕麦氮代谢特性、根系特性及紫花苜蓿结瘤特性在各生育期和氮素水平下表现为不分隔>尼龙网分隔>塑料分隔≥单作,且差异显著。紫花苜蓿的氮代谢酶活性、氮含量、氮积累量在现蕾期和初花期时均表现为单作显著大于不分隔和尼龙网分隔(P<0.05),根系平均直径和根系体积在各生育期和氮素水平下表现为单作>塑料分隔>尼龙网分隔>不分隔,且单作显著大于不分隔。在两个氮素水平下,各生育期的紫花苜蓿和燕麦的氮代谢酶活性、干物质重、氮含量、氮积累量、根表面积、根平均直径、根体积、根系活力均表现为N210(施氮水平)>N21(不施氮水平),而紫花苜蓿总根瘤重、总根瘤数、有效根瘤数、有效/根瘤数均表现为N210<N21,且在初花期时不同根系分隔方式间的差距最大。因此,在紫花苜蓿/燕麦间作体系中,种间根系互作越紧密,越有利于燕麦根系的生长和根系活力的提高,增强燕麦氮同化能力,促进紫花苜蓿结瘤固氮并将由此产生的氮素部分继续转移给燕麦,增强间作系统中种间氮营养的互补利用,以达到紫花苜蓿/燕麦间作体系内的种间氮营养高效回馈,从而有效提高了间作体系中氮素的利用效率;且适宜氮素的添加和生育期的推进,使得种间根系互作不断加强,加强了种间氮素的互补利用,促进其间作体系内氮素的高效利用。

关键词: 紫花苜蓿, 燕麦, 间作, 根系分隔模式, 氮素互馈特征

Abstract:

In this study, we explored the effects of root barriers on interspecific nitrogen competition and mutual feeding in an alfalfa/oat intercropping system using a bucket soil culture method. The nitrogen metabolism characteristics and root characteristics of alfalfa and oat plants, as well as the nodulation characteristics of alfalfa plants, were investigated at different growth stages, under two different nitrogen levels, and with different root barriers. The root barrier treatments could be ranked, from highest to lowest values of nitrogen metabolism characteristics and root characteristics of oat, nodulation of alfalfa at different growth stages, and nitrogen levels, as follows: No barrier>nylon mesh barrier>plastic barrier≥monoculture, and the differences among these treatments were significant. The activities of nitrogen metabolism enzymes, the nitrogen concentration, and nitrogen accumulation in alfalfa in the budding stage and initial blooming stage were significantly higher in the monoculture treatment than in the no barrier and nylon mesh barrier treatments (P<0.05). The root barrier treatments could be ranked, from largest to smallest root average diameter and root volume across all growth stages and nitrogen levels, as follows: Monoculture>plastic barrier>nylon mesh barrier>no barrier. The root average diameter and root volume were significantly higher in the monoculture treatment than in the no barrier treatment. The activities of nitrogen metabolism enzymes, dry weight, nitrogen concentration, nitrogen accumulation, root surface area, root average diameter, root volume, and root activity of alfalfa and oat at different growth stages were higher in the N210 (nitrogen application) treatment than in the N21 treatment (no added nitrogen). The total nodule weight, total nodule number, effective nodule number, and effective/nodule number of alfalfa were lower in the N210 treatment than in the N21 treatment. Therefore, in the alfalfa/oat intercropping system, closer interspecific root interactions are conducive to oat root growth and root activity, nitrogen assimilation by oat, nodulation and nitrogen fixation by alfalfa, and transfer of nitrogen from alfalfa to oat. Such conditions can enhance the complementary utilization of nitrogen by both species, and improve the feedback of interspecific nitrogen nutrition in the alfalfa/oat intercropping system. These results show that closer interspecific root interactions can effectively improve nitrogen-use efficiency in this intercropping system. These findings also show that the addition of nitrogen at an appropriate dose to promote growth at the early period can strengthen the interspecific root interaction and the complementary utilization of nitrogen, thereby improving nitrogen-use efficiency in this intercropping system.

Key words: alfalfa, oat, intercropping, root barriers, nitrogen mutual feeding characteristics