福建省耕地土壤交换性钙空间分布特征及影响因子分析

Spatial Distribution Characteristics and Main Driving Factors of Exchangeable Calcium in Farmlands of Fujian Province

【目的】交换性钙含量是衡量土壤钙丰缺状况的重要指标,剖析耕地土壤交换性钙的空间分布特征及影响因子,可为耕地土壤钙肥管理提供重要参考依据。【方法】本研究以福建省耕地土壤为研究对象,收集了2016~2019年期间1900个土壤监测点数据,量化不同自然条件(海拔、年平均降水量)、土壤性质(土壤交换性镁、速效钾、pH、有机质、土壤类型和质地)以及作物类型对土壤交换性钙的影响,并通过随机森林模型分析这些影响因子对土壤交换性钙的相对重要性。【结果】福建省耕地土壤交换性钙平均含量为519 mg kg^(−1),49.3%的地区低于400 mg kg^(−1),31.6%的地区在400~800 mg kg^(−1)之间。随着土壤交换性镁、pH和有机质的增加,显著提高了土壤交换性钙含量;海拔高度的增加显著降低了土壤交换性钙含量。水稻土和砖红壤交换性钙含量分别为650 mg kg^(−1)和632 mg kg^(−1),显著高于黄壤。稻-菜轮作和蔬菜种植体系土壤交换性钙含量显著高于其他作物种植体系。随机森林分析结果显示,土壤交换性镁是影响交换性钙含量的最重要的因素,其次是海拔、土壤pH和作物类型,而年均降雨量、土壤质地、土壤速效钾、土壤有机质和土壤类型影响较小。【结论】福建省土壤交换性钙含量总体较低,建议通过增施钙肥提高土壤交换性钙含量。在钙肥施肥中,应充分考虑当地气候条件、土壤性质、作物类型等因素,提高钙利用效率,促进作物产量和品质提升。

[Objective]Soil exchangeable calcium(Ca)is an important indicator to evaluate the extent of soil Ca deficiency.The objective of this study was to investigate the spatial distribution characteristics and influencing factors of exchangeable Ca of arable soils in Fujian Province,and to provide a reference basis for the soil Ca fertilizer management.[Method]The soil of farmland in Fujian Province was took as the research object.The data of 1900 soil monitoring sites in Fujian Province during 2016 to 2019 were collected to quantify the effects of different natural conditions(altitude and mean annual precipitation),soil properties(soil exchangeable magnesium,soil available potassium,pH,soil organic matter,soil type,and soil texture),and crop systems on soil exchangeable Ca.Besides,the relative importance of these influencing factors to soil exchangeable Ca was clarified by random forest model(RF).[Result]The soil exchangeable Ca concentration was 519 mg kg^(−1)in average,lower than 400 mg kg^(−1)in 49.3%of the area,and between 400~800 mg kg^(−1)in 31.6%of the area.The increase of soil exchangeable magnesium concentration,pH and soil organic matter significantly increased soil exchangeable Ca concentration,while the increase of altitude significantly decreased soil exchangeable Ca concentration.The exchangeable Ca concentrations of paddy soil and latosol soil were 650 mg kg^(−1)and 632 mg kg^(−1),which were significantly higher than that of yellow soil.The soil exchangeable Ca concentrations of rice vegetable rotation system and vegetable system were significantly higher than those of other cropping systems.In addition,RF analysis indicated that the exchangeable magnesium was the most important factor impacting the exchangeable Ca concentration,followed by altitude,soil pH and crop type,while the mean annual precipitation,soil texture,soil available potassium,soil type and soil organic matter content showed little influence.[Conclusion]Overall,the soil exchangeable Ca concentrations in Fujian Province were generally low,which is suggested to be improved with application of more Ca fertilizers.In Ca fertilizer application,local climatic conditions,soil properties and crop types should be fully considered to improve Ca utilization efficiency and promote crop yield and quality.