Применение методов площадной интерполяции при определении зон потенциального плодородия почв сельскохозяйственных земель

Abstract

The article presents one of the possible options for improving the methodology for identifying zones of potential soil fertility. The necessity of using areal interpolation as the only method of geostatistical analysis that takes into account the area of input objects is proved. To check the data for a Gaussian normal distribution, it is necessary to use several verification methods, since when evaluating only statistical parameters, significant (in the case of phosphorus, abnormal) deviations were found, however, when evaluating histograms and quartile-quartile plots, it is necessary to bring the data to a normal distribution was relevant only for humus and phosphorus. The main advantages and disadvantages of the areal interpolation method are shown. With a significant deviation from the normal distribution, in the absence of built-in functions for automated reduction of data to the Gaussian distribution, one of the few ways can be the logarithm of the data. After zoning, it is necessary to perform a reverse translation to the original values for a representative visualization of the results. As a result of the selection of theoretical semivariograms-deconvolutions, the degrees of spatial dependence and optimal distances for the studied properties are determined. It is clear that the lag of acidity and potassium content is 1000 m and 1050 m, respectively. For phosphorus, it is 1300 m. For the humus content, the lag is much lower—440 m. The maximum autocorrelation distance is typical for potassium and humus—2330 and 1528 m; the minimum for phosphorus is 637. The reliability of the cartograms of agrochemical properties is confirmed by the calculated root-mean-square errors. The deviations of pH values are in the range of up to 0.15 units. The highest mean square error of interpolation is observed in weakly acidic soils. The error in the interpolated values of humus from the initial data is inherent in anthropogenically transformed soils. The root-mean-square error of phosphorus values can be estimated as insignificant. The largest errors in K2O—in isolated cases, they reach 120 mg/ha in the central and eastern parts of the region. The resulting map of potential soil fertility was used to determine the relationship with the granulometric composition of soils. A low level is observed on sandy and sandy loam soils, a high level—on loams. Also, the productivity is affected by the relief of the territory—in the dissected areas, productivity is lower than on the plains.