Spatial Variability of Selected Soil Attributes under Agricultural Land Use System in a Mountainous Watershed, Ethiopia
Affiliation(s)
1 Gondar Agricultural Research Center, Gondar, Ethiopia. 2 Institute of Hydraulics and Rural Water Management, University of Natural Resources and Life Sciences, Vienna, Austria. 3 International Center for Agricultural Research in the Dry Areas, Amman, Jordan.
1 Gondar Agricultural Research Center, Gondar, Ethiopia. 2 Institute of Hydraulics and Rural Water Management, University of Natural Resources and Life Sciences, Vienna, Austria. 3 International Center for Agricultural Research in the Dry Areas, Amman, Jordan.
ABSTRACT
In the Ethiopian Highlands, research projects were often measuring soil attributes of spatially structured point data but soil variability at a watershed scale is not clearly defined. This study was conducted to assess the correlation among selected soil attributes and to illustrate the spatial pattern and dependence of neighboring observations. The 53.7 km2 study watershed was divided into a 500 m by 500 m square grid using arcgis and at the center of each grid soil samples from 0 to 25 cm depth were collected within 184 locations. The descriptive statistics revealed available phosphorous (AP) had the largest coefficient of variation (CV = 104) while pH was the least variable. There was a positive link between elevation and SOC whereas bulk density (ρd) and pH indicated an inverse relationship with elevation and SOC. The value for nugget/sill of ρd, pH and elevation are less than 0.25, and depicts that it has strong spatial autocorrelation. The value for nugget/ sill of SOC, and TN found between 0.25 and 0.75, and indicate that they have moderate spatial autocorrelation. With regard to AP, the value for nugget/sill is more than 0.75, which displays a weak spatial autocorrelation. Semivariograms of ρd, pH and elevation were best fitted to Gaussian model whereas SOC, TN and AP were best fitted to exponential function. Generally, the study verified that soil measurements taken at the given scale through regular sampling interval were adequate to capture the spatial dependence of numerous initial soil assessments in the study watershed.
In the Ethiopian Highlands, research projects were often measuring soil attributes of spatially structured point data but soil variability at a watershed scale is not clearly defined. This study was conducted to assess the correlation among selected soil attributes and to illustrate the spatial pattern and dependence of neighboring observations. The 53.7 km2 study watershed was divided into a 500 m by 500 m square grid using arcgis and at the center of each grid soil samples from 0 to 25 cm depth were collected within 184 locations. The descriptive statistics revealed available phosphorous (AP) had the largest coefficient of variation (CV = 104) while pH was the least variable. There was a positive link between elevation and SOC whereas bulk density (ρd) and pH indicated an inverse relationship with elevation and SOC. The value for nugget/sill of ρd, pH and elevation are less than 0.25, and depicts that it has strong spatial autocorrelation. The value for nugget/ sill of SOC, and TN found between 0.25 and 0.75, and indicate that they have moderate spatial autocorrelation. With regard to AP, the value for nugget/sill is more than 0.75, which displays a weak spatial autocorrelation. Semivariograms of ρd, pH and elevation were best fitted to Gaussian model whereas SOC, TN and AP were best fitted to exponential function. Generally, the study verified that soil measurements taken at the given scale through regular sampling interval were adequate to capture the spatial dependence of numerous initial soil assessments in the study watershed.
Cite this paper
Addis, H. , Klik, A. and Strohmeier, S. (2015) Spatial Variability of Selected Soil Attributes under Agricultural Land Use System in a Mountainous Watershed, Ethiopia. International Journal of Geosciences, 6, 605-613. doi: 10.4236/ijg.2015.66047.
Addis, H. , Klik, A. and Strohmeier, S. (2015) Spatial Variability of Selected Soil Attributes under Agricultural Land Use System in a Mountainous Watershed, Ethiopia. International Journal of Geosciences, 6, 605-613. doi: 10.4236/ijg.2015.66047.
References
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http://dx.doi.org/10.1016/S0016-7061(03)00078-8 [3] Khosla, R. (2010) Precision Agriculture: Challenges and Opportunities in a Flat World. 19th World Congress of Soil Science, Soil Solutions for a Changing World, Brisbane, 1-6 August 2010, 26-28. [4] Nielsen, D.R., Biggar, J.W. and Erh, K.T. (1973) Spatial Variability of Field-Measured Soil-Water Properties. University of California, Division of Agricultural Sciences, Oakland. [5] Smith, H.F. (1938) An Empirical Law Describing Heterogeneity in the Yields of Agricultural Crops. The Journal of Agricultural Science, 28, 1-23. http://dx.doi.org/10.1017/S0021859600050516 [6] Webster, R. and Cuanalo, H.E. (1975) Soil Transect Correlograms of North Oxfordshire and Their Interpretation. Journal of Soil Science, 26, 176-194.
http://dx.doi.org/10.1111/j.1365-2389.1975.tb01942.x [7] Jabro, J.D., Stevens, W.B., Evans, R.G. and Iversen, W.M. (2010) Spatial Variability and Correlation of Selected Soil Properties in the AP Horizon of a CRP Grassland. Applied Engineering in Agriculture, 26, 419-428. http://dx.doi.org/10.13031/2013.29957 [8] Abu, S.T. and Malgwi, W.B. (2011) Spatial Variability of Soil Physico-Chemical Properties in Kadawa Irrigation Project in Sudan Savanna Agroecology of Nigeria. International Journal of Agricultural Research, 6, 714-735. http://dx.doi.org/10.3923/ijar.2011.714.735 [9] Aimrun, W., Amin, M.S.M., Ahmad, D., Hanafi, M.M. and Chan, C.S. (2007) Spatial Variability of Bulk Soil Electrical Conductivity in a Malaysian Paddy Field: Key to Soil Management. Paddy and Water Environment, 5, 113-121. http://dx.doi.org/10.1007/s10333-007-0072-z [10] Schloeder, C.A., Zimmerman, N.E. and Jacobs, M.J. (2001) Comparison of Methods for Interpolating Soil Properties Using Limited Data. Soil Sciences Society of America Journal, 65, 470-479.
http://dx.doi.org/10.2136/sssaj2001.652470x [11] Tsegaye, T. and Hill, R.L. (1998) Intensive Tillage Effects on Spatial Variability of Soil Test, Plant Growth, and Nutrient Uptake Measurements. Soil Science, 163, 155-165.
http://dx.doi.org/10.1097/00010694-199802000-00009 [12] Yost, R.S., Uehara, G. and Fox, R.L. (1982) Geostatistical Analysis of Soil Chemical Properties of Large Land Areas. I. Semi-Variograms. Soil Science Society of America Journal, 46, 1028-1032.
http://dx.doi.org/10.2136/sssaj1982.03615995004600050028x [13] Vieira, S.R., Hatfield, J.L., Nielsen, D.R. and Biggar, J.W. (1983) Geostatistical Theory and Application to Variability of Some Agronomical Properties. University of California, Division of Agricultural Sciences, Oakland. [14] Goovaerts, P. (1999) Geostatistics in Soil Science: State-of-the-Art and Perspectives. Geoderma, 89, 1-45. http://dx.doi.org/10.1016/S0016-7061(98)00078-0 [15] Voltz, M. and Webster, R. (1990) A Comparison of Kriging, Cubic Splines and Classification for Predicting Soil Properties from Sample Information. Journal of Soil Science, 41, 473-490.
http://dx.doi.org/10.1111/j.1365-2389.1990.tb00080.x [16] Cambardella, C.A., Moorman, T.B., Parkin, T.B., Karlen, D.L., Novak, J.M., Turco, R.F. and Konopka, A.E. (1994) Field-Scale Variability of Soil Properties in Central Iowa Soils. Soil Science Society of America Journal, 58, 1501-1511. http://dx.doi.org/10.2136/sssaj1994.03615995005800050033x [17] Cassel, D.K., Wendroth, O. and Nielsen, D.R. (2000) Assessing Spatial Variability in an Agricultural Experiment Station Field: Opportunities Arising from Spatial Dependence. Agronomy Journal, 92, 706-714. http://dx.doi.org/10.2134/agronj2000.924706x [18] Stenger, R., Priesack, E. and Beese, F. (2002) Spatial Variation of Nitrate-N and Related Soil Properties at the Plot-Scale. Geoderma, 105, 259-275. http://dx.doi.org/10.1016/S0016-7061(01)00107-0 [19] Worsham, L., Markewitz, D. and Nibbelink, N. (2010) Incorporating Spatial Dependence into Estimates of Soil Carbon Contents under Different Land Covers. Soil Science Society of America Journal, 74, 635-646. http://dx.doi.org/10.2136/sssaj2008.0412 [20] Mohr, P.A. (1963) The Geology of Ethiopia. Vol. 1, University College of Addis Ababa Press, Addis Ababa. [21] Smith, K.A., Mullins, C.E., et al. (1991) Soil Analysis: Physical Methods. Marcel Dekker, Inc., New York. [22] Peech, M. (1965) Hydrogen Ion Activity. In: Black, C.A., et al., Eds., Methods of Soil Analysis, Part 2, American Society of Agronomy, Madison, 914-926. [23] De Vos, B., Lettens, S., Muys, B. and Deckers, J.A. (2007) Walkley-Black Analysis of Forest Soil Organic Carbon: Recovery, Limitations and Uncertainty. Soil Use and Management, 23, 221-229.
http://dx.doi.org/10.1111/j.1475-2743.2007.00084.x [24] Olsen, S.R. (1954) Estimation of Available Phosphorus in Soils by Extraction with Sodium Bicarbonate. [25] Jackson, M.L. and Barak, P. (2005) Soil Chemical Analysis: Advanced Course. Parallel Press, Madison. [26] R Development Core Team (2013) R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna. http://www.R-project.org [27] Webster, R. and Oliver, M.A. (2001) Geostatistics for Environmental Scientists (Statistics in Practice). John Wiley & Sons, Brisbane, Australia. [28] Nielsen, D.R. and Wendroth, O. (2003) Spatial and Temporal Statistics: Sampling Field Soils and Their Vegetation. Catena Verlag, Reiskirchen. Geoscience Publisher, Germany. [29] Goovaerts, P. (1997) Geostatistics for Natural Resources Evaluation. Oxford University Press, New York, 512 p. [30] Robertson, G.P. (2008) GS+: Geostatistics for the Environmental Sciences. Gamma Design Software, Plainwell. [31] Xu, G.C., Li, Z.B., Li, P., Lu, K.X. and Wang, Y. (2013) Spatial Variability of Soil Organic Carbon in a Typical Watershed in the Source Area of the Middle Dan River, China. Soil Research, 51, 41-49.
http://dx.doi.org/10.1071/SR12327 [32] Kidanemariam, A., Gebrekidan, H., Mamo, T., Kibret, K., et al. (2012) Impact of Altitude and Land Use Type on Some Physical and Chemical Properties of Acidic Soils in Tsegede Highlands, Northern Ethiopia. Open Journal of Soil Science, 2, 223-233. http://dx.doi.org/10.4236/ojss.2012.23027 [33] Kirschbaum, M.U. (1995) The Temperature Dependence of Soil Organic Matter Decomposition, and the Effect of Global Warming on Soil Organic C Storage. Soil Biology and Biochemistry, 27, 753-760. http://dx.doi.org/10.1016/0038-0717(94)00242-S [34] Rustad, L.E. and Fernandez, I.J. (1998) Experimental Soil Warming Effects on CO2 and CH4 Flux from a Low Elevation Spruce-Fir Forest Soil in Maine, USA. Global Change Biology, 4, 597-605.
http://dx.doi.org/10.1046/j.1365-2486.1998.00169.x [35] Li, H. and Reynolds, J.F. (1995) On Definition and Quantification of Heterogeneity. Oikos, 73, 280-284. http://dx.doi.org/10.2307/3545921
[1] Jenny, H. (1994) Factors of Soil Formation: A System of Quantitative Pedology. Courier Corporation, Chelmsford. [2] Sun, B., Zhou, S. and Zhao, Q. (2003) Evaluation of Spatial and Temporal Changes of Soil Quality Based on Geostatistical Analysis in the Hill Region of Subtropical China. Geoderma, 115, 85-99.
http://dx.doi.org/10.1016/S0016-7061(03)00078-8 [3] Khosla, R. (2010) Precision Agriculture: Challenges and Opportunities in a Flat World. 19th World Congress of Soil Science, Soil Solutions for a Changing World, Brisbane, 1-6 August 2010, 26-28. [4] Nielsen, D.R., Biggar, J.W. and Erh, K.T. (1973) Spatial Variability of Field-Measured Soil-Water Properties. University of California, Division of Agricultural Sciences, Oakland. [5] Smith, H.F. (1938) An Empirical Law Describing Heterogeneity in the Yields of Agricultural Crops. The Journal of Agricultural Science, 28, 1-23. http://dx.doi.org/10.1017/S0021859600050516 [6] Webster, R. and Cuanalo, H.E. (1975) Soil Transect Correlograms of North Oxfordshire and Their Interpretation. Journal of Soil Science, 26, 176-194.
http://dx.doi.org/10.1111/j.1365-2389.1975.tb01942.x [7] Jabro, J.D., Stevens, W.B., Evans, R.G. and Iversen, W.M. (2010) Spatial Variability and Correlation of Selected Soil Properties in the AP Horizon of a CRP Grassland. Applied Engineering in Agriculture, 26, 419-428. http://dx.doi.org/10.13031/2013.29957 [8] Abu, S.T. and Malgwi, W.B. (2011) Spatial Variability of Soil Physico-Chemical Properties in Kadawa Irrigation Project in Sudan Savanna Agroecology of Nigeria. International Journal of Agricultural Research, 6, 714-735. http://dx.doi.org/10.3923/ijar.2011.714.735 [9] Aimrun, W., Amin, M.S.M., Ahmad, D., Hanafi, M.M. and Chan, C.S. (2007) Spatial Variability of Bulk Soil Electrical Conductivity in a Malaysian Paddy Field: Key to Soil Management. Paddy and Water Environment, 5, 113-121. http://dx.doi.org/10.1007/s10333-007-0072-z [10] Schloeder, C.A., Zimmerman, N.E. and Jacobs, M.J. (2001) Comparison of Methods for Interpolating Soil Properties Using Limited Data. Soil Sciences Society of America Journal, 65, 470-479.
http://dx.doi.org/10.2136/sssaj2001.652470x [11] Tsegaye, T. and Hill, R.L. (1998) Intensive Tillage Effects on Spatial Variability of Soil Test, Plant Growth, and Nutrient Uptake Measurements. Soil Science, 163, 155-165.
http://dx.doi.org/10.1097/00010694-199802000-00009 [12] Yost, R.S., Uehara, G. and Fox, R.L. (1982) Geostatistical Analysis of Soil Chemical Properties of Large Land Areas. I. Semi-Variograms. Soil Science Society of America Journal, 46, 1028-1032.
http://dx.doi.org/10.2136/sssaj1982.03615995004600050028x [13] Vieira, S.R., Hatfield, J.L., Nielsen, D.R. and Biggar, J.W. (1983) Geostatistical Theory and Application to Variability of Some Agronomical Properties. University of California, Division of Agricultural Sciences, Oakland. [14] Goovaerts, P. (1999) Geostatistics in Soil Science: State-of-the-Art and Perspectives. Geoderma, 89, 1-45. http://dx.doi.org/10.1016/S0016-7061(98)00078-0 [15] Voltz, M. and Webster, R. (1990) A Comparison of Kriging, Cubic Splines and Classification for Predicting Soil Properties from Sample Information. Journal of Soil Science, 41, 473-490.
http://dx.doi.org/10.1111/j.1365-2389.1990.tb00080.x [16] Cambardella, C.A., Moorman, T.B., Parkin, T.B., Karlen, D.L., Novak, J.M., Turco, R.F. and Konopka, A.E. (1994) Field-Scale Variability of Soil Properties in Central Iowa Soils. Soil Science Society of America Journal, 58, 1501-1511. http://dx.doi.org/10.2136/sssaj1994.03615995005800050033x [17] Cassel, D.K., Wendroth, O. and Nielsen, D.R. (2000) Assessing Spatial Variability in an Agricultural Experiment Station Field: Opportunities Arising from Spatial Dependence. Agronomy Journal, 92, 706-714. http://dx.doi.org/10.2134/agronj2000.924706x [18] Stenger, R., Priesack, E. and Beese, F. (2002) Spatial Variation of Nitrate-N and Related Soil Properties at the Plot-Scale. Geoderma, 105, 259-275. http://dx.doi.org/10.1016/S0016-7061(01)00107-0 [19] Worsham, L., Markewitz, D. and Nibbelink, N. (2010) Incorporating Spatial Dependence into Estimates of Soil Carbon Contents under Different Land Covers. Soil Science Society of America Journal, 74, 635-646. http://dx.doi.org/10.2136/sssaj2008.0412 [20] Mohr, P.A. (1963) The Geology of Ethiopia. Vol. 1, University College of Addis Ababa Press, Addis Ababa. [21] Smith, K.A., Mullins, C.E., et al. (1991) Soil Analysis: Physical Methods. Marcel Dekker, Inc., New York. [22] Peech, M. (1965) Hydrogen Ion Activity. In: Black, C.A., et al., Eds., Methods of Soil Analysis, Part 2, American Society of Agronomy, Madison, 914-926. [23] De Vos, B., Lettens, S., Muys, B. and Deckers, J.A. (2007) Walkley-Black Analysis of Forest Soil Organic Carbon: Recovery, Limitations and Uncertainty. Soil Use and Management, 23, 221-229.
http://dx.doi.org/10.1111/j.1475-2743.2007.00084.x [24] Olsen, S.R. (1954) Estimation of Available Phosphorus in Soils by Extraction with Sodium Bicarbonate. [25] Jackson, M.L. and Barak, P. (2005) Soil Chemical Analysis: Advanced Course. Parallel Press, Madison. [26] R Development Core Team (2013) R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna. http://www.R-project.org [27] Webster, R. and Oliver, M.A. (2001) Geostatistics for Environmental Scientists (Statistics in Practice). John Wiley & Sons, Brisbane, Australia. [28] Nielsen, D.R. and Wendroth, O. (2003) Spatial and Temporal Statistics: Sampling Field Soils and Their Vegetation. Catena Verlag, Reiskirchen. Geoscience Publisher, Germany. [29] Goovaerts, P. (1997) Geostatistics for Natural Resources Evaluation. Oxford University Press, New York, 512 p. [30] Robertson, G.P. (2008) GS+: Geostatistics for the Environmental Sciences. Gamma Design Software, Plainwell. [31] Xu, G.C., Li, Z.B., Li, P., Lu, K.X. and Wang, Y. (2013) Spatial Variability of Soil Organic Carbon in a Typical Watershed in the Source Area of the Middle Dan River, China. Soil Research, 51, 41-49.
http://dx.doi.org/10.1071/SR12327 [32] Kidanemariam, A., Gebrekidan, H., Mamo, T., Kibret, K., et al. (2012) Impact of Altitude and Land Use Type on Some Physical and Chemical Properties of Acidic Soils in Tsegede Highlands, Northern Ethiopia. Open Journal of Soil Science, 2, 223-233. http://dx.doi.org/10.4236/ojss.2012.23027 [33] Kirschbaum, M.U. (1995) The Temperature Dependence of Soil Organic Matter Decomposition, and the Effect of Global Warming on Soil Organic C Storage. Soil Biology and Biochemistry, 27, 753-760. http://dx.doi.org/10.1016/0038-0717(94)00242-S [34] Rustad, L.E. and Fernandez, I.J. (1998) Experimental Soil Warming Effects on CO2 and CH4 Flux from a Low Elevation Spruce-Fir Forest Soil in Maine, USA. Global Change Biology, 4, 597-605.
http://dx.doi.org/10.1046/j.1365-2486.1998.00169.x [35] Li, H. and Reynolds, J.F. (1995) On Definition and Quantification of Heterogeneity. Oikos, 73, 280-284. http://dx.doi.org/10.2307/3545921