草地学报

草地学报 ›› 2018, Vol. 26 ›› Issue (1): 114-124.DOI: 10.11733/j.issn.1007-0435.2018.01.014

• 研究论文 • 上一篇    下一篇

种植密度对紫花苜蓿不同生育时期叶片C、N、P生态化学计量的影响

刘文兰1,2,4, 师尚礼1,2, 田福平3, 罗永忠4   

  1. 1. 甘肃农业大学草业学院, 甘肃 兰州 730070;
    2. 草业生态系统教育部重点实验室 中-美草地畜牧业可持续发展研究 中心 甘肃省草业工程实验室, 甘肃 兰州 730070;
    3. 中国农业科学院兰州畜牧与兽药研究所 农业部兰州黄土高原生态 环境重点野外科学观测试验站, 甘肃 兰州 730050;
    4. 甘肃农业大学林学院, 甘肃 兰州 730070
  • 收稿日期:2017-04-14 修回日期:2018-02-09 出版日期:2018-02-15 发布日期:2018-05-25
  • 通讯作者: 师尚礼
  • 作者简介:刘文兰(1976-),女,宁夏中卫人,博士研究生,主要从事植物生态和园林学研究,E-mail:liuwl@gsau.edu.cn
  • 基金资助:

    国家现代牧草产业技术体系（CARS-35）；国家自然科学基金面上项目（31372368）；中国农业科学院科技创新工程专项资金项目（CAAS-ASTIP-2014-LIHPS-08）；国家自然科学基金项目（31560238）；甘肃省教育厅高等学校基本科研经费（2015a-071）；甘肃农业大学林学院中青年科研基金项目资助

Effects of Planting Density on Leaf C, N, P Ecological Stoichiometry in Different Growth Stages of Alfalfa

LIU Wen-lan1,2,4, SHI Shang-li1,2, TIAN Fu-ping3, LUO Yong-zhong4   

  1. 1. Pratacultural College, Gansu Agricultural University, Lanzhou, Gansu Province 730070, China;
    2. Key Laboratory of Ecosystem, Ministry of Education, Sino-US center for Grazingland Ecosystem Sustainability, Pratacultural Engineering Laboratory of Gansu Province, Lanzhou, Gansu Province 730070, China;
    3. Lanzhou Institute of Husbandry and Pharmaceutical Sciences of Chinese Academy of Agricultural Sciences, The Lanzhou Scientific Observation and Experiment Field Station of Ministry of Agriculture for Ecological system in the Loess Plateau Area, Lanzhou, Gansu Province 730050 China;
    4. College of Forestry, Gausu Agriculture University, Lanzhou, Gansu Province 730070, China
  • Received:2017-04-14 Revised:2018-02-09 Online:2018-02-15 Published:2018-05-25

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摘要：

以紫花苜蓿甘农3号（Medicago satial L.‘Gannong No.3’）为材料，设计了210，263，315，368，420 万株·hm-2的5个种植密度，在种植第二年第一茬的分枝期、现蕾期和初花期留茬5cm刈割，刈割部分从下到上以植株枝条第3茎节及以下作为下层，第4茎节至第6茎节作为中层，以第7茎节及以上作为上层，研究不同密度对紫花苜蓿不同生育时期群落空间各层叶片C、N、P生态化学计量的影响。结果表明，随种植密度的增大，同一生育时期各层叶片C、N、P含量均下降，而叶片C∶N和C∶P则升高，分枝期和现蕾期的叶片C含量及初花期的叶片P含量对密度处理较为敏感；随着紫花苜蓿生育期的推进，相同密度下紫花苜蓿各层叶片C、N、P含量均减小，而C∶N和C∶P则增大；同一生育时期相同种植密度下，叶片C、N、P含量及N∶P的大小顺序为上层 > 中层 > 下层，C∶N和C∶P为下层 > 中层 > 上层。分枝期和现蕾期平均叶片N∶P均处于11~12之间，这2个时期紫花苜蓿受N限制；初花期N∶P为11.63~14.48，紫花苜蓿受N、P共同限制。紫花苜蓿适宜的种植密度为368 万株·hm-2。

关键词: 紫花苜蓿, 种植密度, 生育时期, 叶片, 分层, 生态化学计量

Abstract:

A field experiment of Medicago sativa L.'Gannong No.3’was arranged with five kinds of planting densities(2 100 000 、 2 630 000、3 150 000、3 680 000 、4 200 000 stem·hm-2). Alfalfa plant was cut to 5 cm stubble height at branching stage, bud stage and early flowering stage of the second year, and cutting parts were divided into three layers, from bottom to the third node as lower layer, from 4th to 6th node as middle layer, the seventh node and above as upper layer. Carbon (C), nitrogen (N), and phosphorus (P) of alfalfa leaf in different layers were tested to study the response to density treatment at different growth stages. The results showed that the contents of leaf C, N and P decreased, and C∶N ratio and C∶P ratio both increased with the increase of planting density. Leaf C content at branching stage and bud stage and the leaf P content at early flowering stage were sensitive to density treatment. With the growth of alfalfa plant, the contents of C, N and P reduced under the same planting density, and the ratio of C∶N and C∶P increased. The order of the contents of leaf C,N and P and the ratio of N∶P were upper leaf > middle leaf > lower leaf, and the ratio of C∶N and C∶P were both lower leaf > middle leaf > upper leaf. The ratio of N∶P was 11~12 at branching stage and bud stage, suggesting that N limitation occurred at the two stages; the leaf N∶P ratio at early flowering stage was 11.63~14.48, implying that N and P limitation occurred. The appropriate planting density for alfalfa was 3 680 000 stem·hm-2

Key words: Alfalfa, Planting density, Different growth stages, Leaf, Layering, Ecological stoichiometry

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