基于Daycent模型的张掖地区天然草地土壤有机碳储量研究

Study on soil organic carbon storage in naturalgrasslands of the Zhangye region based on thedaycent model

摘要:

【目的】 以张掖天然草地土壤有机碳储量为研究对象，将Daycent 模型参数本地化，使其适用于张掖地区天然草地土壤有机碳储量的模拟，从而研究张掖地区天然草地土壤有机碳储量空间分布和影响因素。【方法】 利用CENTURY 模型的每日时间步长版本Daycent 模型，根据张掖地区气象站点的日值气象数据、土壤数据和2022 年6-7 月实测数据，模拟1979-2020 年张掖地区天然草地土壤有机碳储量空间分布，并分析其影响因素。【结果】 张掖地区天然草地土壤有机碳储量呈现“东西高，中间低”的空间分布格局，总土壤有机碳储量与慢性土壤有机碳储量的变化趋势基本一致；其中2022 年6 月天然草地土壤有机碳储量在肃南裕固族自治县最高，为36. 181 kg/m²，土壤有机碳储量在山丹县最低，为4. 661 kg/m²。从影响因素来看，海拔与天然草地土壤有机碳储量分布一致；土壤理化性质与天然草地土壤有机碳储量之间的相关性较低；降水量与天然草地土壤有机碳储量之间呈现正相关，温度与天然草地土壤有机碳储量之间呈现负相关。【结论】 DAYCENT 模型可以有效地模拟张掖天然草地土壤有机碳储量，模型的适应性很强，张掖地区天然草地土壤有机碳储量受诸多因素影响，慢性土壤有机碳库含量对张掖天然草地土壤碳储量的影响最大。研究对张掖地区天然草地碳汇管理具有一定的指导意义。

Abstract:

【Objective】 This study aimed to localizethe parameters of the Daycent model to simulate soil organiccarbon stock in natural grassland in Zhangye area. The goal was to investigate the spatial distribution and influencingfactors of SOC stock in this region.【Method】 The Daycent model，a daily time-step version of the CENTURYmodel，was used to simulate the spatial distribution of soil organic carbon storage in natural grasslands in Zhangyearea from 1979 to 2020. The simulation was based on daily value meteorological data from local weather stations，soildata and fieldmeasurements takenin June and July 2022. The localized model was usedto analyze the influencing factors【Result】 The spatial distribution of soil organic carbon stock followed a pattern of "high in the east and west，lowin the middle"，with the trends intotal soil organic carbon stock and chronic soil organic carbon stock being similar. InJune 2022，the highest soil organic carbon was observed in Su ′nan Yugur autonomous county，at 36. 181 kg/m²，whilethe lowestwas in Shandan County，at 4. 661 kg/m². Elevation was found to align with the distribution of soil organiccarbon stocks in natural grasslands，whilecorrelations between soil physicochemical properties and soil organiccarbon stocks were generally low. Positive correlations were found between precipitation and soil organic carbon，whereas temperature had a negative correlation with soil organic carbon.【Conclusion】 The Daycent model effectivelysimulated soil organic carbon stock in Zhangye′s natural grasslands and demonstrated high adaptability. Soil organiccarbon in Zhangye is influenced by various factors，with the chronic soil organic carbon pool having the greatest im ‐pact. Understanding the distribution of soil organic carbon can inform future management practices for natural grasslandcarbon sinks in Zhangye.