Figures (7)  Tables (7)

    • Figure 1. 

      Location and elevation maps of the study areas: (a) Konya Sub-Region, (b) Eastern Black Sea Sub-Region.

    • Figure 2. 

      Slope maps of the study areas: (a) Eastern Black Sea Sub-Region, (b) Konya Sub-Region.

    • Figure 3. 

      Land use land cover map of the Eastern Black Sea Sub-Region (CORINE, 2018).

    • Figure 4. 

      Land use land cover map of the Konya Sub-Region (CORINE 2018).

    • Figure 5. 

      Spatial distribution patterns of soil samplings over the study areas: (a) Black Sea Sub Region, (b) Konya Sub-Region.

    • Figure 6. 

      The modelling architecture designed to determine the biogeographical regions.

    • Figure 8. 

      Geographical distribution patterns of the SOC-based biogeographical intensity levels for (a) the Eastern Black Sea Sub-Region along with the (c) R2 value, and (b) the Konya Sub-Region along with the (d) R2 value.

    • Land use/land cover Area (ha) Ratio (%) Land use/land cover Area (ha) Ratio (%)
      Continuous urban fabric 36.0 0.1 Complex cultivation patterns 2,794.0 5.8
      Discontinious urban fabric 239.0 0.5 Land principally occupied by agriculture with 4,614.0 9.7
      Industrial or commercial units 27.0 0.1 Broad-leaved forest 4,279.0 9.0
      Roas ans rail networks and associated land 22.1 0.0 Coniferous forest 4,914.0 10.3
      Port areas 1.0 0.0 Mixed forest 5,438.0 11.4
      Airports 1.0 0.0 Natural grasslands 2,043.0 4.3
      Mineral extraction sites 40.0 0.1 Transitional woodlans/shrub 5,560.0 11.6
      Dump sites 0.2 0.0 Beaches, dunes, sands 22.0 0.0
      Construction sites 25.0 0.1 Bare rocks 1,789.0 3.7
      Sport and leisure facilities 0.1 0.0 Sparsely vegetated areas 7,023.0 14.7
      Non-irrigated arable land 2,335.5 4.9 Inland marshes 18.0 0.0
      Permanently irrigated arandla land 895.0 1.9 Annual crops associated with permanent crop 0.1 0.0
      Fruit trees and berry plantations 4,434.0 9.3 Water bodies 209.0 0.4
      Pastures 1,008.0 2.1 Total 47,767.0 100.0

      Table 1. 

      Proportional distribution of land use/ land cover map of the Eastern Black Sea Sub-Region.

    • Land use/Land cover Area (ha) Ratio (%) Land use/Land cover Area (ha) Ratio (%)
      Continuous urban fabric 33.0 0.1 Complex cultivation patterns 1,063.0 2.4
      Discontinuous urban fabric 826.0 1.9 Land principally occupied by agriculture with
      significant areas natural vegetation      		 2,241.0 5.2
      Industrial or commercial units 222.0 0.5 Broad-leaved forest 365.0 0.8
      Road and rail network and associated land 4.0 0.0 Coniferous forest 318.0 0.7
      Airports 22.0 0.1 Mixed forest 107.0 0.2
      Mineral extraction sites 65.0 0.1 Natural grasslands 6,009.0 13.8
      Dump sites 10.0 0.0 Sclerophylous vegetation 94.0 0.2
      Construction sites 28.0 0.1 Transitional woodlans/shrub 3,167.0 7.3
      Green urban areas 4.0 0.0 Beaches, dunes, sands 4.0 0.0
      Sport and leisure facilities 6.0 0.0 Bare rocks 261.0 0.6
      Non-irrigated arable land 3,530.0 8.1 Sparsely vegetated areas 7,019.0 16.1
      Permanently irrigated land 7,880.0 18.1 Inland marshes 543.0 1.2
      Rice fields 8.0 0.0 Salt marshes 2,536.0 5.8
      Vineyards 41.0 0.1 Salines 89.0 0.2
      Fruits trees and berry plantations 270.0 0.6 Water bodies 2,456.0 5.6
      Pastures 4,276.0 9.8 Total 43,497 100.0

      Table 2. 

      Proportional distribution of land use land-cover map of the Konya Sub-Region.

    • Parameter Unit Procedure Ref.
      Texture
      (clay, silt, and sand)      		 % Hydrometer method Bouyoucos, 1951
      pH 1:1 Soil-water suspension (w:v) Soil Survey Staff, 1992
      EC dS m−1 Soil-water suspension (w:v) Soil Survey Staff, 1992
      CaCO3 % Calcimetric method Soil Survey Staff, 1992
      Organic matter % Walkley-Black method Nelson & Sommers, 1982
      BD g cm−3 Undisturbed condition Blacke & Hartge, 1986

      Table 3. 

      Methods applied for the analysis of soil physical and chemical properties.

    • Class Index
      C1. Climate
      C1.1. Annual Aridity Index 0.20−0.50 (semi-arid) 1
      0.50−0.65 (dry-subhumid) 2
      0.65−1.0 (semi-humid) 3
      > 1.0 (humid and very humid) 4
      C1.2. Annual average number of rainy days 50−80 (low) 1
      80−10 (moderate) 2
      110−140 (high) 4
      140−170 (very high) 3
      C1.3. Dry period (May to September) average number of rainy days 13−26 (low) 1
      26−39 (moderate) 2
      39−52 (high) 3
      52−65 (very high) 4
      C1.4. Annual average maximum air temperature (°C) 13.5−15.0 (cool) 3
      15.0−16.5 (warm) 4
      16.5−18.0 (hot) 2
      18.0−19.5 (very hot) 1
      C1.5. Warm period (May to September) average maximum air temperature (°C) 22−24 (warm) 4
      24−26 (very warm) 3
      26−28 (hot) 2
      28−30 (very hot) 1
      C2. Geo-topography
      C2.1. Parent material - Alluvial deposits 1
      - Basic-ultrabasic magmatics, melange, ophiolitic and serpentine, shale, metamorphic rocks such as schist, phyllite clay stone, marl. 2
      - Siltstone, mudstone, conglomerate, travertine, limestone, dolomite, marble 3
      - Acid magmatic, cherty, gneiss, dunes, volcanic ashes, tuff, agglomerate, breccia, evaporates, pebble stone, sand stone 4
      C2.2. Slope (%) 0−5 4
      5−15 3
      15−35 2
      35−+ 1
      C2.3. Aspect East 1
      South 2
      West 3
      North 4
      C2.4. Elevation (m) 0−250 4
      250−750 3
      750−1,500 2
      1,500−+ 1
      C3. Vegetation
      C3.1. Land use / Land cover Artificial areas 1
      Agriculture 2
      Pasture 3
      Forest 4
      C3.2. Vegetation intensity (%) < 25 (very low) 1
      25−50 (low) 2
      50−75 (moderate) 3
      75+ (very high) 4
      C4. Soil
      C4.1. Soil depth (cm) 0−20 1
      20−50 2
      50−90 3
      90−+ 4
      C4.2. Organic matter (%) < 1 1
      1−2 2
      2−3 3
      > 3 4
      C4.3. Erosion (ton/ha/year) 0−5 4
      5−10 3
      10−20 2
      20−+ 1
      C4.4. pH 6.5−7.5 Slightly acid or alkaline 4
      5.5−6.5 Slightly to moderate acid 3
      7.5−8.5 Slightly to moderate alkaline 2
      < 5.5 − > 8.5 Strong acid or alkaline 1
      C4.5. Lime content - CaCO3 (%) 0−5 (low) 2
      5−10 (moderate) 4
      10−20 (high) 3
      > 20 (very high) 1
      C4. 6. Bulk density (g cm3) 1.00−1.20 (low) 4
      1.21−1.40 (moderate) 3
      1.41−1.55 (high) 2
      > 1.55 (very high) 1
      C4.7. Soil texture Fine (C < %45, CL, SiL, SCL) 4
      Very fine (fC > %45, SiCL, SC) 3
      Medium (L, Si, SiL, fSL) 2
      Coarse (S, SL, LS) 1

      Table 4. 

      Main criteria, sub criteria, and their index values.

    • Criteria Mean SD CV Variance Min. Max. Skewness Kurtosis
      BD (g cm−3) 1.41 0.12 1.49 0.01 0.82 2.31 −1.17 3.68
      OM (%) 3.44 2.17 14.64 4.71 0.02 14.66 1.13 1.56
      Clay (%) 22.57 12.54 69.44 157.45 1.81 69.44 0.39 −0.14
      Sand (%) 47.00 17.93 87.37 321.69 5.01 87.37 −0.62 0.52
      Silt (%) 25.53 10.27 71.76 105.59 1.10 71.76 −0.22 1.26
      pH 4.84 2.74 8.50 7.50 3.14 8.50 −0.78 −0.72
      CaCO3 (%) 3.82 7.45 64.98 55.6 0.01 64.98 2.75 8.50
      C (ton ha−1) 81.68 53.99 350.92 2914.97 0.46 351.38 1.27 2.10
      BD: Bulk density, SD: standard deviation, CV: coefficient of variation, Min: Minimum, Max: Maximum.

      Table 5. 

      Descriptive statistics for physico-chemical properties of soils in the Eastern Black Sea Sub-region.

    • Criteria Mean SD CV Variance Min. Max. Skewness Kurtosis
      OM (%) 1.70 1.12 9.71 1.27 0.09 9.80 2.33 8.69
      Clay (%) 30.37 13.51 77.32 182.71 3.62 80.94 0.62 0.41
      Sand (%) 40.34 16.65 90.76 277.55 1.38 92.14 0.32 0.13
      Silt (%) 29.28 10.59 68.44 112.21 1.59 70.03 0.34 0.88
      BD (g cm−3) 1.34 0.14 0.71 0.02 1.10 1.81 0.35 −0.56
      pH 7.51 0.31 2.27 0.10 6.76 8.43 −0.46 1.57
      CaCO3 (%) 26.27 17.71 84.50 313.86 0.01 84.50 0.50 −0.47
      C (ton ha−1) 36.33 26.63 266.56 709.16 2.12 268.66 2.88 12.52
      BD: Bulk density, SD: standard deviation, CV: coefficient of variation, Min: Minimum, Max: Maximum.

      Table 6. 

      Descriptive statistics for physico-chemical properties of soils in the Konya Sub-Region.

    • Interpolation models Semivariogram models RMSE value
      Eastern Black
      Sea Sub-Region      		 Konya
      Sub-Region
      Inverse Distance Weighting (IDW) IDW−1 0.233 0.480
      IDW-2 0.231 0.474
      IDW-3 0.230 0.512
      Radial Basis Functions (RBF) TPS 0.236 0.626
      CRS 0.235 0.476
      SWT 0.236 0.479


      Kriging      		 Ordinary Gaussian 0.103 0.487
      Exponential 0.104 0.485
      Spherical 0.104 0.487
      Simple Gaussian 0.105 0.485
      Exponential 0.106 0.485
      Spherical 0.104 0.484
      Universal Gaussian 0.105 0.487
      Exponential 0.106 0.487
      Spherical 0.106 0.486
      TPS: Thin Plate Spline, CRS: Completely Regularized Spline, SWT: Spline with Tension. Bold numbers are the lowest values of RMSE.

      Table 7. 

      Interpolation models and RMSE of soil criteria.