Organic carbon content-baesd prediction and influencing factors of black soil layer thicknesses
Black soil layer thicknesses,anessential attribute of black soil,serves as a significant indicator for measuring the fertility and erosion degree of black soil.Their spatial prediction holds critical significance for supporting China's black land conservation and ensu-ring food security.Considering the diagnostic characteristics of black soil layers in soil system classification,this study regarded soil lay-ers with organic carbon content higher than 6×10-3 of soil parent materials as black soil layers.Moreover,it derived the calculation for-mula for the thicknesses of black soil layers relying on the exponential distribution pattern of organic carbon in the vertical soil profile.Based on the 62 896 topsoil and 15 687 deepsoil organic carbon data obtained from the multi-purpose regional geochemical survey,this study conducted detailed spatial prediction of the thicknesses of black soil layers in the Songliao Plain and analyzed their relationship with soil types and climate factors.Key findings are as follows:(1)The thicknesses of black soil layers in the Songliao Plain range from 0 to 165 cm,with a median of 23.33 cm;(2)The spatial distribution of black soil layers exhibits significant heterogeneity,char-acterized by thin southwestern and thick northeastern portions;(3)The black soil layers of swampy soil and peat soil manifest the lar-gest average thicknesses between 60 and 80 cm,followed by those of typical black soil(average thickness:56 cm)and those of albic soil and meadow soil(average thickness:40～50 cm);(4)The spatial distributions of the thicknesses of black soil layers are closely associated with climatic conditions,primarily showing a significant negative correlation with temperature and a positive correlation with rainfall;(5)The mean annual temperature of 0℃is a significant temperature threshold for the development of thick black soil layers.Above this temperature,the average thickness of black soil layers exceeds 80 cm and no longer changes with temperature.With global warming,the southward shift of this 0℃is otherm may significantly influence the thicknesses of black soil layers.
black landthickness of a black soil layersoil organic carbonmulti-purpose regional geochemical surveyNortheast China
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