Acta Agrestia Sinica

Acta Agrestia Sinica ›› 2023, Vol. 31 ›› Issue (4): 1115-1124.DOI: 10.11733/j.issn.1007-0435.2023.04.021

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Changes of Soil, Microorganisms, Enzymes and Stoichiometry During the Uncultivature of Alfalfa Farmland

YU Zong-kai1, JING Yu-du2,3, LIU Li1, LIU Xiao-wei1, ZHANG Qiang1, CHENG Jie4, GUO Liang2,5   

  1. 1. College of Grassland Agriculture, Northwest A&F University, Yangling, Shaanxi Province 712100, China;
    2. Research Center for Soil and Water Conservation and Ecological Environment, Chinese Academy of Sciences and Ministry of Education, Yangling, Shaanxi Province 712100, China;
    3. University of Chinese Academy of Sciences, Beijing 100049, China;
    4. Northwest Surveying Planning and Designing Institute of National Forestry and Grassland Administration, Xian, Shaanxi Province 710048, China;
    5. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi Province 712100, China
  • Received:2022-10-31 Revised:2022-11-30 Published:2023-04-28

苜蓿地撂荒过程中土壤-微生物-胞外酶及化学计量的变化

于宗恺1, 景煜都2,3, 刘励1, 刘小伟1, 张强1, 程杰4, 郭梁2,5   

  1. 1. 西北农林科技大学草业与草原学院, 陕西 杨凌 712100;
    2. 中国科学院教育部水土保持与生态环境研究中心, 陕西 杨凌 712100;
    3. 中国科学院大学, 北京 100049;
    4. 国家林业和草原局西北调查规划设计院, 陕西 西安 710048;
    5. 西北农林科技大学 黄土高原土壤侵蚀与旱地农业国家重点实验室, 陕西 杨凌 712100
  • 通讯作者: 郭梁,E-mail:guoliang2014@nwsuaf.edu.cn
  • 作者简介:于宗恺(1998-),男,汉族,甘肃白银人,硕士研究生,主要从事草地土壤及微生物研究,E-mail：1046315338@qq.com
  • 基金资助:
    国家自然科学基金(41701606)；陕西省自然科学基础研究计划(2021 JM-093)；中央高校基本科研业务费(2452020009)资助

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Abstract: Alfalfa (Medicago sativa L.) is widely planted in the Loess Plateau as a good plant for land restoration. However,with the rural population migration and the change of land use,the issue of mass uncultivation of alfalfa artificial farmlands has attracted a wide attention. To explore the changes of soil quality of the alfalfa uncultivated farmlands,this study analyzed the soil nutrients,microorganisms,enzyme activities in relation to the soil carbon (C),nitrogen (N) and phosphorus (P) cycles and their stoichiometric changes in alfalfa farmlands during cultivation and uncultivation for different years (5 and 10 years). The results indicated that:overall,the C and N contents of soil and microbe increased with abandoned years,while enzyme activities and stoichiometry of C and N changed a little. The P content of soil and microbe significantly decreased with abandoned years,but enzyme activity and stoichiometry of P increased in varying degrees. By the further analysis,it was found out that:compared with other soil layers,the contents of C,N,P and their enzyme activities in topsoil (0~20 cm) are higher;the changing trends of the soil C,N,P and enzyme activities in this layer was similar to the overall trends of the profile. The C,N,P contents and their enzyme activities increased firstly and then decreased in 20~40 cm sub-surface layer and 80~100 cm deep layer. All parameters in these two layers were 40%~80% lower than those in the topsoil. In addition,the results of correlation analysis showed that the soil in alfalfa uncultivated farmlands was gradually degrading from P deficiency,which could be improved by applying of phosphorus fertilizer.

Key words: Loess Plateau, Alfalfa farmland, Uncultivated years, Soil quality, Ecological stoichiometry

摘要： 紫花苜蓿(Medicago sativa L.)作为优良修复草种在黄土高原广泛种植，然而随着农村人口迁移及土地利用变化，苜蓿人工草地大量弃置的问题已引起广泛关注。为研究苜蓿弃置草地土壤质量变化规律，本研究分析了不同弃置年限(0年、5年和10年)苜蓿草地土壤养分、微生物量、参与土壤碳氮磷(C，N，P)循环的胞外酶活性及其化学计量变化。结果表明：总体上，土壤和微生物C，N含量随弃置年限呈增加趋势，而C，N相关胞外酶活性和化学计量变化幅度较小；土壤和微生物P含量随弃置年限增加而显著降低，但P相关胞外酶活性及化学计量均有不同程度的增加。进一步分析发现：相较于其他土层，表层(0~20 cm)土壤C，N，P含量及其酶活性较高，其变化趋势与总体结果相似；亚表层土壤(20~40 cm)和(80~100 cm)深层土壤C，N，P含量及其酶活性呈先增后减趋势，且各指标较于表层土壤均降低40%~80%。相关分析表明弃置草地土壤由于P匮乏而逐步退化，可通过补施磷肥改善。

关键词: 黄土高原, 苜蓿草地, 弃置年限, 土壤质量, 生态化学计量

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