This study attempts to evaluate interpolation technique for mapping spatial distribution of some ... more This study attempts to evaluate interpolation technique for mapping spatial distribution of some soil characteristics at the Lower Seyhan River Basin in Cukurova (Turkey). These soil characteristics may help to improve agricultural land management practices. In the study area, 7 parallel transects each having 150 m of length were selected at 5 m intervals, and 104 soil samples were collected. In these samples, calcium carbonate, organic matter, cation exchange capacity and clay content (from particle size distribution) were determined. Inverse distance weighting (IDW) interpolation and employing of GIS technology were applied on the results. Calcium carbonate, organic matter, cation exchange capacity and clay content values derived from IDW interpolation were consistent with the results of the soil analysis. The verity of the interpolation technique was tested by employing cross validation. Interpolation of organic matter values showed a high mean error in 30-60 cm depth (2.82%) while this high deviation was not the case with the other parameters studied.
Soil organic carbon, the major component of soil organic matter, an important indicator for the s... more Soil organic carbon, the major component of soil organic matter, an important indicator for the soil fertility, is not only extremely important in soil processes but also highly related to the climate change, soil/land degradation and soil ecosystem services. Spatially explicit soil organic carbon information system was a great need for Turkeys’ soils. This study aimed at developing a territorial national geographical database for soil organic carbon of top soils (0-30 cm) in Turkey. In the first stage of project, 7742 top soil samples provided from different research projects for the period of 2008-2009 that represent the national territory and different land uses were analyzed to determine carbon content of soils. In the second stage, digital soil mapping methodology that applies geostatistical processes of geoferenced soil data has been used to produce maps of soil organic carbon. We expect that Geospatial Soil Organic Carbon Information System can serve as an important spatially...
Spatial and temporal variation of hydraulic properties of soil acts as an eliminating factor agai... more Spatial and temporal variation of hydraulic properties of soil acts as an eliminating factor against measuring them in large scale with limited number of samples. The routine soil input predictors for deriving a PTF are sand, silt and clay percentages, bulk density and organic matter content. These routine predictors lack an adequate description of soil structural properties. Soil aggregates and their stability, however, have a strong influence on physical properties of soil. This study was carried out to identify the impact of soil aggregates stability as an extra input predictor on the performance of PTFs derived to estimate water retention curve. A data set containing 135 samples, collected from different part of Turkey, is used. Eight pseudo continuous neural network based PTFs were derived using different combination of input predictors. Result shows the lowest error belongs to a PTF in which AS has been employed on top of other extra input predictors. Sensitivity analysis also...
This study attempts to evaluate interpolation technique for mapping spatial distribution of some ... more This study attempts to evaluate interpolation technique for mapping spatial distribution of some soil characteristics at the Lower Seyhan River Basin in Cukurova (Turkey). These soil characteristics may help to improve agricultural land management practices. In the study area, 7 parallel transects each having 150 m of length were selected at 5 m intervals, and 104 soil samples were collected. In these samples, calcium carbonate, organic matter, cation exchange capacity and clay content (from particle size distribution) were determined. Inverse distance weighting (IDW) interpolation and employing of GIS technology were applied on the results. Calcium carbonate, organic matter, cation exchange capacity and clay content values derived from IDW interpolation were consistent with the results of the soil analysis. The verity of the interpolation technique was tested by employing cross validation. Interpolation of organic matter values showed a high mean error in 30-60 cm depth (2.82%) while this high deviation was not the case with the other parameters studied.
Soil organic carbon, the major component of soil organic matter, an important indicator for the s... more Soil organic carbon, the major component of soil organic matter, an important indicator for the soil fertility, is not only extremely important in soil processes but also highly related to the climate change, soil/land degradation and soil ecosystem services. Spatially explicit soil organic carbon information system was a great need for Turkeys’ soils. This study aimed at developing a territorial national geographical database for soil organic carbon of top soils (0-30 cm) in Turkey. In the first stage of project, 7742 top soil samples provided from different research projects for the period of 2008-2009 that represent the national territory and different land uses were analyzed to determine carbon content of soils. In the second stage, digital soil mapping methodology that applies geostatistical processes of geoferenced soil data has been used to produce maps of soil organic carbon. We expect that Geospatial Soil Organic Carbon Information System can serve as an important spatially...
Spatial and temporal variation of hydraulic properties of soil acts as an eliminating factor agai... more Spatial and temporal variation of hydraulic properties of soil acts as an eliminating factor against measuring them in large scale with limited number of samples. The routine soil input predictors for deriving a PTF are sand, silt and clay percentages, bulk density and organic matter content. These routine predictors lack an adequate description of soil structural properties. Soil aggregates and their stability, however, have a strong influence on physical properties of soil. This study was carried out to identify the impact of soil aggregates stability as an extra input predictor on the performance of PTFs derived to estimate water retention curve. A data set containing 135 samples, collected from different part of Turkey, is used. Eight pseudo continuous neural network based PTFs were derived using different combination of input predictors. Result shows the lowest error belongs to a PTF in which AS has been employed on top of other extra input predictors. Sensitivity analysis also...
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