中国典型农田土壤有机碳密度的空间分异及影响因素

Spatial Differentiation of Soil Organic Carbon Density and Influencing Factors in Typical Croplands of China

农田土壤有机碳密度(SOCD)是衡量土壤肥力和土壤质量的重要指标.为理解我国农田SOCD空间分异特征及其影响因素,基于中国生态系统研究网络19个典型农田生态站2005~2015年SOCD的监测数据,利用地理探测器方法,分析了农田SOCD空间分异的影响因素.结果表明,我国不同站点农田SOCD平均值变化范围为0.83~4.97 kg·m^(-2),并呈现出湿润季风区高于干旱半干旱地区的空间分异特征.在不同土地利用方式下,水稻田SOCD明显高于其他类型的农田,并且其表现出显著增加的趋势(P<0.05),增加速率为0.13 kg·(m^(2)·a)^(-1).土壤理化性状和降水量是影响农田SOCD空间分布的重要因素,特别是土壤碱解氮含量对农田SOCD空间分布影响最大,且它分别与纬度、土壤类型、降水量及土壤p H等因素交互后影响力显著增强,本研究结果对我国农田温室气体减排增汇提供重要的科学依据.

Cropland soil organic carbon density( SOCD) is an important indicator for measuring soil fertility and soil quality. To understand the spatial differentiation characteristics of cropland SOCD and its influencing factors across China,a dataset on the cropland SOCD of 19 typical stations during 2005-2015 was collected from the China Ecosystem Research Network. The geodetector method was used to analyze the influencing factors affecting the spatial patterns of cropland SOCD. The results indicated that the mean cropland SOCD ranged from 0. 83 kg·m^(-2) to 4. 97 kg·m^(-2) in different stations across China,and was higher in humid monsoon regions than in arid and semi-arid regions. Under different land use patterns,the SOCD of paddy fields was higher than that of other croplands and showed a tendency of significant increase from 2005 to 2015,reaching 0. 13 kg·( m^(2)·a)^(-1). The soil physical and chemical properties and precipitation were important influencing factors that affected the spatial patterns of cropland SOCD. In particular,the soil alkaline nitrogen content had the greatest impact on the cropland SOCD patterns. Furthermore,the interaction forces between the soil alkaline nitrogen content and latitude,soil type,precipitation,and soil p H were clearly strengthened. The findings can provide an important scientific basis for reducing cropland greenhouse gas emissions and increasing soil carbon sequestration across China.