陈锐峰, 曾全超, 胡漫, 周连昊, 马茂华. 不同柑橘种植年限土壤胞外酶生态化学计量特征及其驱动因子解析[J]. 中国生态农业学报 (中英文), 2024, 32(8): 1−11. DOI: 10.12357/cjea.20240151
引用本文: 陈锐峰, 曾全超, 胡漫, 周连昊, 马茂华. 不同柑橘种植年限土壤胞外酶生态化学计量特征及其驱动因子解析[J]. 中国生态农业学报 (中英文), 2024, 32(8): 1−11. DOI: 10.12357/cjea.20240151
CHEN R F, ZENG Q C, HU M, ZHOU L H, MA M H. Ecological stoichiometry characteristics of soil extracellular enzymes under different citrus ages and analysis of their driving factors[J]. Chinese Journal of Eco-Agriculture, 2024, 32(8): 1−11. DOI: 10.12357/cjea.20240151
Citation: CHEN R F, ZENG Q C, HU M, ZHOU L H, MA M H. Ecological stoichiometry characteristics of soil extracellular enzymes under different citrus ages and analysis of their driving factors[J]. Chinese Journal of Eco-Agriculture, 2024, 32(8): 1−11. DOI: 10.12357/cjea.20240151

不同柑橘种植年限土壤胞外酶生态化学计量特征及其驱动因子解析

Ecological stoichiometry characteristics of soil extracellular enzymes under different citrus ages and analysis of their driving factors

  • 摘要: 土壤胞外酶生态化学计量特征可用于评估微生物对资源和养分的获取情况, 是评价土壤肥力和微生物活性的重要指标。然而, 高强度集约化柑橘种植对土壤胞外酶计量特征的影响机制尚不清楚。为探讨集约化农业种植对土壤酶化学计量特征及其对种植年限的响应, 本研究以三峡库区河岸带不同种植年限柑橘为研究对象, 采集根际土壤, 测定与碳氮磷循环相关的胞外酶活性和功能微生物基因丰度, 通过胞外酶生态化学计量特征去评估土壤微生物对氮磷养分及资源的需求状况。结果表明, 柑橘种植年限的增加会提高土壤有效氮和有效磷的含量, 其中磷素累积更为明显。种植30 a的柑橘土壤有效磷含量是5 a柑橘土壤的3.5倍, 其远远高于柑橘生长需求阈值。柑橘种植年限增加会显著降低土壤碳、磷循环相关酶活性, 增加氮获取酶活性。从功能基因角度来看, 编码碱性磷酸酶的phoD基因丰度显著下降, 从4.84×107 copies·g−1下降至9.24×106 copies·g−1。土壤功能微生物基因丰度改变是导致碱性磷酸酶活性降低的直接因素。土壤酶化学计量特征也随着柑橘种植年限的增加而改变。土壤酶矢量角度由58.21°降低至18.70°, 表明土壤微生物对养分的需求由磷限制转换为氮限制。低柑橘种植年限土壤微生物以磷限制为主, 而高柑橘年限土壤微生物以氮限制为主。高强度农业种植过程中, 需减少磷肥施用, 增加有机肥等碳源投入, 提高微生物活性。研究结果可为高强度集约化柑橘种植土壤质量提升和果园的可持续管理提供理论依据。

     

    Abstract: The ecological stoichiometric characteristics of soil extracellular enzymes can be used to evaluate the acquisition of resources and nutrients by microorganisms, can sensitively reflect the metabolic characteristics of soil microorganisms, and are important indicators for evaluating soil fertility and microbial activity. Intensive agriculture is characterized by the long-term application of large amounts of chemical fertilizers, which often leads to changes in the composition and activity of microbial communities in the soil. However, the mechanism by which high-intensity intensive citrus cultivation affects soil extracellular enzyme stoichiometric characteristics is unclear. In order to investigate the effects of intensive agricultural cultivation on the stoichiometric characteristics of soil enzymes and their response to planting duration, this study focused on citrus orchards of varying planting durations in the riparian zones of the Three Gorges Reservoir area. Rhizosphere soils were collected to measure extracellular enzyme activities related to carbon, nitrogen, and phosphorus cycling. The ecological stoichiometry of extracellular enzymes was utilized to assess the demand for nitrogen, phosphorus, and resources by soil microorganisms. Results indicated that with increasing citrus planting duration, the content of available nitrogen and phosphorus in the soil increased, particularly with a significant accumulation of soil phosphorus. The soil phosphorus content in citrus orchards planted for 30 years was 3.5 times higher than that of 5-year-old orchards, far exceeding the threshold required for citrus growth. In addition, in citrus soils with long citrus planting years, other different forms of phosphorus also accumulate in large amounts. In citrus soils with different planting years, the enzyme activities related to the acquisition of carbon, nitrogen and phosphorus showed significant differences. Increasing citrus planting duration significantly reduced the activity of soil enzymes related to carbon and phosphorus cycling while increasing nitrogen acquisition enzyme activity. From a functional gene perspective, the abundance of the phoD gene encoding alkaline phosphatase significantly decreased from 4.84×107 copies·g−1 to 9.24×106 copies·g−1. Changes in the abundance of soil functional microbial genes directly contributed to the reduction in alkaline phosphatase activity. The stoichiometric characteristics of soil enzymes also changed with increasing citrus planting duration, enzyme vector model revealed that with the soil enzyme vector angle decreasing from 58.21° to 18.70°, indicating a transition in soil microbial nutrient demand from phosphorus limitation to nitrogen limitation. Soil microbial communities in low-duration citrus orchards were primarily P-limited, whereas those in high-duration orchards were primarily N-limited. In the process of high-intensity agricultural planting, it is necessary to reduce the application of phosphate fertilizers and increase the input of carbon sources to promote phosphorus through carbon and alleviate microbial nutrient limitations Moreover alkaline conditioners should be appropriately added to soils with high citrus planting years to alleviate soil acidification. These findings provide a theoretical basis for improving soil quality and the sustainable management of orchards under intensive citrus cultivation.

     

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