Ecological stoichiometry and spatial variation characteristics of soil nutrients in a cultivation area of Zhangjiakou City, Hebei Province

By applying geostatistics, ecological chemometrics and GIS techniques, the characteristics of the content, trend distribution, spatial variability and distribution of biogenic elements of N, P, K₂O, CaO, MgO, S, Mo, Mn, Fe₂O₃, B, Corg, pH and other parameters in the surface soil of a planting area in Wanquan District, Zhangjiakou City, Hebei Province were studied.The results showed that Corg belonged to the strongly differentiated variation type with a coefficient of variation of 71.54%, while the rest of the elements belonged to the weak or uniform differentiation type.N, P, K₂O and pH were in the very abundant and abundant classes, while S, Mo, Mn, Fe₂O₃, B and Corg were in the deficient and extremely deficient classes.By comparing the errors in different trend orders superimposed on the block gold coefficient analysis, it was tentatively determined that the study area could be classified into three prediction types, namely, no trend prediction, first-order trend prediction and second-order trend prediction, with K₂O, CaO, MgO, S, Mn and Corg mainly influenced by the structural type, and N, P, Mo, Fe₂O₃, B and pH mainly influenced by a mixture of structural and stochastic properties, among which S and Mo variance functions surface with weak directionality.Ecological chemometrics showed that the average content of biogenic elements K₂O > Corg > N > P > S.Soil CNR and NPR were mainly controlled by soil Corg and N, and the vertical direction showed a predominantly epistatic and smooth distribution, supplemented by mutational and sawtooth distribution.Finally, ordinary kriging interpolation clearly shows that N, P, K₂O, CaO, MgO, and Mn all show obvious anomalous areas in the watershed range from northeast to southwest, mainly controlled by river migration and transport, with N and P in the key area being of the trapezoidal type, K₂O, CaO, and pH of the inner concave type, S and Mo of the outer convex type, and MgO, Fe₂O₃, Mn, B, and Corg belong to the jump type.