不同连栽代次桉树人工林土壤团聚体中有机碳组分的积累和转化

崔宇鸿; 叶绍明; 卢志锋; 燕羽; 蒋晨阳

doi:10.12171/j.1000-1522.20240144

不同连栽代次桉树人工林土壤团聚体中有机碳组分的积累和转化

Accumulation and transformation of organic carbon components in soil aggregates of Eucalyptus spp. plantations across different continuous cropping generations

摘要

摘要:
目的探究不同连栽代次桉树人工林土壤中有机碳组分的积累与转化特征，以期揭示环境因素对土壤有机碳组分积累和转化过程的影响，进而为提高桉树生产力和土壤管理提供科学依据。
方法以广西博白县博白林场第1、2、3代桉树人工林为研究对象，采用干筛法将收集的0 ~ 40 cm土壤分为 > 2 mm、1 ~ 2 mm、0.25 ~ 1 mm和 < 0.25 mm粒径的团聚体以评估土壤团聚体稳定性，并测量不同团聚体中有机碳组分（包括活性有机碳、缓性有机碳和惰性有机碳）的含量和储量，利用冗余分析和偏最小二乘法结构方程模型揭示影响土壤有机碳积累和转化的关键因素。
结果（1）连栽显著降低了土壤团聚体的稳定性和各有机碳组分的含量和储量。（2）土壤各有机碳组分含量随团聚体粒径的增加而下降，而储量的分布规律则相反。（3）冗余分析和偏最小二乘法结构方程模型证明，土壤团聚体稳定性是影响土壤有机碳积累的主要因素，连栽抑制了惰性有机碳向活性有机碳的转化，导致土壤有机碳总体有效性下降。
结论连栽主要通过改变土壤团聚体的分布和稳定性，进而调控桉树人工林土壤有机碳组分的积累和转化。研究结果有助于理解桉树人工林土壤有机碳的积累和转化过程中土壤团聚体调控机制。

Abstract:
Objective This paper aims to investigate the accumulation and transformation characteristics of soil organic carbon (SOC) components in Eucalyptus spp. plantations of different continuous planting generations, so as to reveal the impact of environmental factors on the accumulation and transformation processes of SOC components, thereby providing a scientific basis for improving Eucalyptus spp. productivity and soil management.
Method Taking the first, second, and third generations of Eucalyptus spp. plantations in Bobai Forest Farm, Bobai County, Guangxi Province of southern China as the research objects, soil samples from 0–40 cm depth were collected. The soils were fractionated into aggregates of > 2 mm, 1–2 mm, 0.25–1 mm, and < 0.25 mm using dry sieving to evaluate soil aggregate stability. The contents and storage of organic carbon components, including active organic carbon, slow organic carbon, and inert organic carbon in different aggregates were measured. Redundancy analysis (RDA) and partial least squares structural equation modeling (PLS-SEM) were used to identify the key factors affecting the accumulation and transformation of SOC.
Result (1) Continuous planting significantly reduced the stability of soil aggregates and decreased the content and storage of various organic carbon components. (2) The contents of each SOC component decreased with increasing aggregate particle size, while the storage distribution showed the opposite trend. (3) RDA and PLS-SEM demonstrated that soil aggregate stability was the main factor influencing SOC accumulation. Continuous planting inhibited the transformation of inert organic carbon into active organic carbon, leading to a decline in the overall effectiveness of SOC.
Conclusion Continuous planting primarily regulates the accumulation and transformation of SOC components in Eucalyptus spp. plantations by altering the distribution and stability of soil aggregates. These findings enhance the understanding of the regulatory mechanisms of soil aggregates in the accumulation and transformation processes of SOC in Eucalyptus spp. plantations.

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