The analysis of influencing factors of soil exchangeable acidity content in northeast Chongqing's tobacco area using Random Forest model and SHAP algorithm
[Background]Exchangeable acidity content is crucial for guiding fertilizer application and regulating soil pH in agricultural practices.This work aims to clarify the effects of environmental factors(climate,topography,parent materials)and planting years on soil exchangeable acidity(EA)content.[Methods]In this paper,the soil exchangeable acidity data of 483 sampling points in the northeast tobacco area of Chongqing were statistically analyzed.The random forest(RF)model was constructed and combined with Shapley Additive exPlanations(SHAP)algorithm to explore the main controlling factors affecting soil exchangeable acidity content.[Results](1)In the study area,the exchangeable acidity content ranged from 1.56-27.50 cmol/kg and showed a significant negative correlation with precipitation,sunshine duration,slope direction,and planting duration.The content of exchangeable acidity was significantly higher in soils developed from Permian limestone than that in soils developed from Triassic limestone.(2)The RF model accounted for 64%of the spatial variation in exchangeable acidity content.The influence of environmental factors on exchangeable acidity content was:climatic factors>parent materials>planting years>topography.(3)The SHAP algorithm indicated that soil exchangeable acidity content had obvious threshold effect under different climatic conditions.When mean annual precipitation,sunshine hours and mean temperature exceed 1250 mm,1290 h and 12℃,respectively,soil exchangeable acidity content decreased and vice versa.[Conclusion]Climate is the predominant environmental factor influencing soil exchangeable acidity variation,with precipitation and sunshine duration being the most influential variables soil exchangeable acidity.The research results can provide reference for the management and regulation of soil acidification in tobacco fields.
万方数据
维普
