【摘要】 2022年7月份，在浑善达克沙地生态系统定位观测研究站观测区域，以浑善达克沙地恢复20 a的4种固沙林[樟子松(Pinus sylvestris)固沙林、杨树(Populus)固沙林、杨柴(Hedysarum laeve)固沙林、黄柳(Salix gordejevii)固沙林]为研究对象，选取自然恢复20 a的固定沙地为对照样地；在距离植被30 cm以内、土层深度为0～20 cm,采用多点混合法，按照每个样品由S型5点等量样品均匀混合采集土壤样品，测定土壤养分质量分数(有机质质量分数、速效氮质量分数、速效磷质量分数、速效钾质量分数)和土壤酶活性(脲酶活性、蔗糖酶活性、中性磷酸酶活性、过氧化氢酶活性);采用主成分分析法、单因素方差分析法、邓肯氏新复极差法、冗余分析法，结合构建的土壤肥力综合指数(SFCI),分析不同植被恢复措施对沙地土壤肥力的影响、不同植被土壤养分与酶活性的关联特性。结果表明：与对照样地相比，杨柴固沙林样地的土壤速效氮质量分数、速效磷质量分数、速效钾质量分数分别提高14.7%、93.3%、32.6%(P<0.05);黄柳固沙林样地的土壤速效氮质量分数提高8.9%(P<0.05);杨树固沙林样地的土壤有机质质量分数、速效氮质量分数、速效磷质量分数、速效钾质量分数分别提高78.5%、58.2%、78.9%、33.2%(P<0.05),土壤脲酶活性、蔗糖酶活性、过氧化氢酶活性分别提高52.2%、153.7%、12.7%(P<0.05);杨树、杨柴、黄柳固沙林样地的土壤肥力综合指数比对照样地分别提高76.4%、40.5%、26.0%(P<0.05);樟子松固沙林样地的土壤养分、土壤酶活性及土壤肥力综合指数均无显著变化。冗余分析表明，土壤速效氮质量分数、有机质质量分数，均与土壤蔗糖酶活性、脲酶活性、中性磷酸酶活性呈极显著正相关(P<0.01);蒙特卡洛检验表明，土壤养分对土壤酶活性的影响力，由大到小依次为速效氮质量分数(影响力为47.5%)、速效钾质量分数(影响力为4.8%)、有机质质量分数(影响力为4.6%)、速效磷质量分数(影响力为2.7%)。杨树固沙林对沙地土壤肥力提升效果最佳；速效氮是影响沙地土壤酶活性的关键因子。更多还原

【Abstract】 In July 2022, at the observation area of the Hunshandake Sandy Land Ecosystem Research Station, four types of sand-fixing forests restored for 20 years in the Hunshandake Sandy Land(Pinus sylvestris sand-fixing forest, Populus sand-fixing forest, Hedysarum laeve sand-fixing forest, and Salix gordejevii sand-fixing forest) were selected as research objects, with a naturally restored fixed sandy land for 20 years as the control plot. Within 30 cm of vegetation and at a soil depth of 0-20 cm, soil samples were collected using the multi-point mixing method, where each sample was uniformly mixed from five equal samples along an S-shaped trajectory. Soil nutrient contents(organic matter, available nitrogen, available phosphorus, available potassium) and soil enzyme activities(urease, sucrase, neutral phosphatase, catalase) were measured. Principal component analysis, one-way analysis of variance, Duncan’s new multiple range test, and redundancy analysis were used, combined with the constructed soil fertility comprehensive index(SFCI), to analyze the effects of different vegetation restoration measures on soil fertility in sandy land and the correlation between soil nutrients and enzyme activities under different vegetation types. The results showed that: Compared with the control plot, the available nitrogen, available phosphorus, and available potassium contents in the H. laeve sand-fixing forest plot increased by 14.7%, 93.3%, and 32.6%(P<0.05), respectively. The available nitrogen content in the S. gordejevii sand-fixing forest plot increased by 8.9%(P<0.05). The organic matter, available nitrogen, available phosphorus, and available potassium contents in the Populus sand-fixing forest plot increased by 78.5%, 58.2%, 78.9%, and 33.2%(P<0.05), respectively, while the urease, sucrase, and catalase activities increased by 52.2%, 153.7%, and 12.7%(P<0.05), respectively. The SFCI values of Populus, H. laeve, and S. gordejevii sand-fixing forest plots increased by 76.4%, 40.5%, and 26.0%(P<0.05) compared to the control plot, respectively. No significant changes were observed in soil nutrients, enzyme activities, or SFCI in the P. sylvestris sand-fixing forest plot. Redundancy analysis showed that soil available nitrogen and organic matter contents were significantly positively correlated with soil sucrase, urease, and neutral phosphatase activities(P<0.01). Monte Carlo testing indicated that the influence of soil nutrients on soil enzyme activities decreased in the order: available nitrogen(47.5% influence), available potassium(4.8%), organic matter(4.6%), and available phosphorus(2.7%). Conclusion: Populus sand-fixing forest had the best effect on improving soil fertility in sandy land, and available nitrogen was a key factor influencing soil enzyme activities in sandy land.更多还原