Determination of the shelterbelts influence on the average productivity of agrophytocenoses based on geostatistical analysis of spatial data and the NDVI

Abstract

Shelterbelts effect positively on the elements of the microclimate, the water regime of soils, the agronomic properties of the soil, soil fertility in the agricultural landscape. The assessment of the influence of the density of shelterbelts on the overall productivity of arable land is poorly studied. In this study, the methodology for assessing of such impact with using GIS technologies is suggested. We propose to use the Normalized Vegetation Index (NDVI), as a standardized index showing the relative biomass of vegetation, averaged for each working area within the studied region for working plots of arable land with an area of more than 25 hectares in the Belgorod oblast. Paired correlation analysis between the density of shelterbelts and arable land productivity showed the weak relationship (R2= 0.124), however, the classification of the density of shelterbelts with the interval of 0.5 km/km2 allowed us to reveal the linear regression dependence y = 0.0059x + 0.5195 (R2 = 0.989) of arable land productivity from the density of shelterbelts. Taking into account that many abiotic factors can affect the yield, we additionally proposed to carry out typing to identify areas of the same type in terms of the relief of the earth’s surface, climatic conditions and productivity. To do this, the spatial clustering (K-means algorithm) was proposed to use. It was revealed that the productivity of agrophytocenoses increases by 10% with the increasing of the density of shelterbelts by 2 times with an average slope steepness of up to 2°. In physical terms, the yield of winter wheat will increase by 0.28 t/ha. Soil-protective crop rotations are an additional factor in increasing the value of the NDVI index on slopes more than 2°.