基于DNDC的茶园土壤碳素空间分异及其影响因素——以福建省安溪县为例

SPATIAL DIFFERENTIATION AND INFLUENCING FACTORS OF SOIL CARBON IN THE TEA PLANTATION BASED ON DNDC MODEL——A CASE STUDY OF ANXI COUNTY, FUJIAN PROVINCE

关键词:  DNDC  安溪茶园  空间统计分析  碳素模拟  温室气体

Key words:  DNDC  tea plantations in Anxi county  spatial statistical analysis  carbon simulation  greenhouse gas

摘要:

目的 通过探究福建省安溪县茶园土壤碳素储量，揭示各碳素指标的空间分异特征及其关键影响因子，有助于为减少茶园温室气体排放和建设生态茶园提供决策支撑。方法 文章运用反硝化分解（denitrification decomposition， DNDC）模型和空间统计分析方法对茶园土壤碳素进行模拟和研究。结果 （1）经过参数率定的DNDC模型对茶园土壤碳素动态循环的模拟具有较好的适用性；（2）安溪茶园土壤有机碳含量丰富，土壤肥力较好。凋落物输入碳是茶园土壤碳素输入的主要来源，平均输入量为505.52 kg/hm²，而通过呼吸作用转化为CO₂排放是茶园土壤碳素输出的重要途径，平均CO₂排放量为883.78 kg/hm²；（3）茶园SOC_10~20cm量、凋落物输入碳量、CH₄排放量、CO₂排放量均呈现空间聚集分布特征，主要分布在安溪县西部的低山与中低山地区；（4） 初始土壤属性中黏粒含量和土壤有机碳含量是影响安溪县茶园土壤碳素空间分异的关键因子，其中土壤黏粒含量对茶园土壤CO₂排放量和CH₄排放量的影响最强且负向作用效果明显。结论 安溪县西部等低山和中低山区域土壤肥力较好，但亦应谨慎对待该区域温室气体排放量较大的问题，可采用茶园合理的管理方式权衡茶园土壤碳素输入和温室气体排放的关系。

Abstract:

Soil carbon stocks in tea plantations in Anxi county, Fujian province, China, are explored to reveal the spatial differentiation of carbon indices and related key influencing factors, which provides macroscopic decision-making support for reducing greenhouse gas emissions from tea plantations and building ecological tea plantations. The denitrification decomposition (DNDC) model and spatial statistical analysis were used to simulate and explore soil carbon dynamics cycle in tea plantations. The results showed that: (1) The DNDC model validated by parameter showed preferably applicability of the simulation of the soil carbon dynamics cycle in tea plantations. (2) The tea plantations in Anxi county boasted rich content of SOC and fertile soil. Litter input carbon was the main source of soil carbon input, averaging 505.52 kg/hm², and the conversion from respiratory action to CO₂ emission was the main way to export soil carbon, averaging 883.78 kg/hm². (3) The content of SOC_10~20cm, litter input carbon, CH₄ emission and CO₂ emission of tea plantation showed spatial aggregation distribution characteristics, which mainly distributed in low mountain and mid-low mountain areas of western Anxi county. (4) Soil clay content and soil organic carbon content in the initial soil properties were the key factors influencing the spatial differentiation of soil carbon in tea plantations in Anxi county. The strongest and negative effect of soil initial clay content on soil CO₂ emissions and CH₄ emissions from tea plantations was evident. In summary, there is better soil productivity in the low and mid-low mountain areas in western Anxi county. However, the issue of higher greenhouse gas emissions in these areas should be carefully considered, and tea garden management practices can be adopted to regulate the relationship between soil carbon input and greenhouse gas emissions in tea plantations.