| 中亚热带不同林龄马尾松林土壤酶学计量特征 |
| 摘要点击 2011 全文点击 576 投稿时间：2021-07-06 修订日期：2021-07-28 |
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| 中文关键词 马尾松 林龄 土壤酶活性 土壤酶化学计量 养分限制 |
| 英文关键词 Pinus massoniana stand age soil enzyme activity soil ecoenzymatic stoichiometry nutrient limitation |
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| 中文摘要 |
| 土壤酶活性是表征土壤微生物养分需求与养分限制状况的重要指标.本文以中亚热带不同林龄（9、17、26、34和43 a）马尾松人工林为研究对象，通过测定β-葡萄糖苷酶（BG）、N-乙酰-β-氨基葡萄糖苷酶（NAG）、亮氨酸氨基肽酶（LAP）、酸性磷酸酶（AP）、多酚氧化酶（POX）和过氧化物酶（POD）活性，并计算土壤酶化学计量比，探讨不同发育阶段马尾松人工林土壤微生物的养分限制状况.结果表明，土壤BG、NAG、AP、POX和POD活性均随着林龄增加呈上升趋势，土壤LAP活性随着林龄的增加呈波动式上升，其中17 a生马尾松林LAP活性最低.土壤酶C：N：P化学计量比约为1：1：0.56与全球生态系统酶C：N：P化学计量比1：1：1相偏离；其中酶C：N随着林龄增加而增加，酶N：P随着林龄增加而减少，二者均在17 a后趋于稳定；酶N：P在林龄间无显著差异；酶化学计量的向量长度在林龄间无显著差异，向量角度随着林龄增加而增加，在17 a后趋于稳定但角度均小于45°.冗余分析（RDA）结果显示，土壤碳质量指数与pH是影响土壤酶活性及其化学计量比的主要因子.结果表明中亚热带不同生长阶段马尾松人工林土壤微生物均受到氮限制且随着林龄增加氮限制有所缓和，而对P的需求逐渐增强.因此，建议未来马尾松人工林的经营应在马尾松生长初期增施氮肥，随着马尾松的生长发育在施氮肥的同时适施磷肥以维持马尾松人工林的生产力和可持续发展. |
| 英文摘要 |
| Soil enzyme activity is an important index to characterize the nutrient requirements and nutrient limitations of soil microorganisms. In this study, Pinus massoniana plantations of different stand ages (9, 17, 26, 34, and 43 a) in mid-subtropical China were taken as the research object; the activities of β-glucosidase (BG), N-acetyl-β-glucosaminidase (NAG), leucine amino-peptidase (LAP), acid phosphatase (AP), polyphenol oxidase (POX), and peroxidase (POD) were determined; and soil enzyme stoichiometric ratios were also calculated to investigate the soil microbial nutrient limitations of P. massoniana plantation development. The results showed that the activities of BG, NAG, AP, POX, and POD were enhanced with the increase in stand age, and the activity of LAP was the lowest at 17 a, which showed a significant difference and fluctuated among the neighboring stand ages. The soil enzyme C:N:P stoichiometric ratio was 1:1:0.56, which deviated from the global ecosystem enzyme C:N:P stoichiometric ratio (1:1:1). The enzyme C:N increased, whereas the enzyme N:P decreased, with increasing stand age, and both ratios tended to be stable after 17 a. There was no significant difference in enzyme N:P among different stand ages. The vector length of enzyme stoichiometry was not significantly different among the five stand ages. The vector angles increased with the increase in stand ages and tended to be stable after 17 a of stand age, but the angles were less than 45°. Redundancy analysis (RDA) revealed that soil carbon quality index and pH were the main factors influencing soil enzyme activity and the associated stoichiometric ratio. Our findings indicated that P. massoniana plantation soil microorganisms at different growth stages were all subjected to N limitation, and the N limitation was alleviated with the increase in stand age; however, the P requirement was gradually enhanced. Therefore, the management of P. massoniana plantations should take care to increase nitrogen fertilizer at the early growth stage of P. massoniana, and more phosphorus fertilizers need to be applied with nitrogen at the late growth stage in order to maintain the productivity and sustainable development of P. massoniana plantations. |
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