CBS ARAZİ KULLANIMI ANALİZİ VE TOPRAK İLE TOPRAK EROZYON RİSKİ ALANLARI TAHMİNİ HARİTALAR: BİR ESTONYA VAKA ÇALIŞMASI

Land use in areas prone to soil erosion processes is one of the most important parameters for evaluating the risk of water and wind erosion. Therefore the estimation of the proportion and location of arable land and permanent (including natural) grasslands in erosion sensitive areas by land use databases, the Estonian soil map and orthophotographs were the goals of the current research. We used the Estonian large scale digital soil map (1:10,000) for estimating areas at risk of wind erosion. We selected fields with a sandy texture over 3 ha and fields of peat soils over 0.5 ha in size in areas with higher wind speeds, mainly in coastal and lakeshore counties. The Estonian soil map identifies three subgroups of soils vulnerable to water erosion. GIS queries and analyses of the Estonian soil map in conjunction with data from ARIB (Agricultural Registers and Information Board) indicated that soils vulnerable to water erosion exist on 40,000 ha of ARIB registered land, of which 16,000 ha is arable land. Although this finding means 40% of agricultural land is at risk from water erosion, the proportion of arable land varies considerably from one county to another (27-54%). The use of water erodible soils for arable land is greater in counties, in which intensity of erosion is low and the proportion of erodible soils is fairly small. Estimates, based on the GIS queries, indicated that wind erodible soils comprised approximately 100,000 ha of Estonia's agricultural land, of which about 32% are high wind erosion risk arable fields. The Universal Soil Loss Equation model enabled us to estimate the average soil erosion intensity of fields covered by natural vegetation as a low rate of 0.04 t ha-1 y-1, even in the high risk areas (i.e counties where the eroded soils are wide spread). However, changes in land use from natural vegetation to intensively managed arable land accelerate the intensity of soil erosion to 0.43 t ha-1 y-1.