Geostatistical and GIS analyses on soil organic carbon concentrations in grassland of southeastern Ireland from two different periods

Abstract A total of 191 soil samples, taken in 1964 from grassland of southeastern Ireland, and 220 samples, taken in 1996 from the same area, were examined for soil organic carbon (SOC). Temporal and spatial changes in SOC concentration after the ca. 30-year interval were evaluated using conventional statistics, geostatistics and geographic information system (GIS) analyses. A lognormal distribution feature was observed for both data sets, and the results of a t-test showed that the difference between them was not significant. Spatial outliers were detected with the index of local Moran's I in order to obtain a robust variogram. Kriging was used for spatial prediction for both data sets using the same grid system. The difference between the two maps was determined using map algebraic functions and showed considerable spatial change. The analysis has enabled the delineation of two discrete sectors in the study area, which have clearly behaved differently: mean increase of SOC concentration in the eastern coastal sector was 30.2% compared to a mean decrease of 16.0% in the inland sector. Changes in land use or cultivation did not adequately account for the spatial difference. The division between the sectors appeared to coincide approximately with and to reflect both hill land and geological patterns. A satisfactory explanation for the difference has not been identified. Thus, a combination of geostatistics and GIS map algebra provides a useful tool for the examination of spatio-temporal changes in the environmental sciences and may detect features that are not discernible when only conventional statistics are used.

[1]  C. Zhang,et al.  Multivariate outlier detection and remediation in geochemical databases. , 2001, The Science of the total environment.

[2]  J. Turner,et al.  Change in organic carbon in forest plantation soils in eastern Australia. , 2000 .

[3]  Z. L. Frogbrook,et al.  Comparing the spatial predictions of soil organic matter determined by two laboratory methods , 2001 .

[4]  Richard Webster,et al.  The development of pedometrics , 1994 .

[5]  N. Batjes,et al.  Mitigation of atmospheric CO2 concentrations by increased carbon sequestration in the soil , 1998, Biology and Fertility of Soils.

[6]  R. Reese.  Geostatistics for Environmental Scientists , 2001 .

[7]  R. Webster,et al.  Optimal interpolation and isarithmic mapping of soil properties. II. Block kriging. , 1980 .

[8]  Alfred Stein,et al.  Spatial variability of soil properties at different scales within three terraces of the Henares River (Spain) , 1998 .

[9]  D. Krige.  A statistical approach to some basic mine valuation problems on the Witwatersrand, by D.G. Krige, published in the Journal, December 1951 : introduction by the author , 1951 .

[10]  C. Monreal,et al.  Influence of tillage practice on carbon sequestration is scale-dependent , 2001 .

[11]  R. Lal,et al.  Crop residue and tillage effects on carbon sequestration in a Luvisol in central Ohio , 1999 .

[12]  M. Van Meirvenne,et al.  Regional characterization of the long‐term change in soil organic carbon under intensive agriculture , 1996 .

[13]  R. Lal,et al.  Soil carbon dynamics in cropland and rangeland. , 2002, Environmental pollution.

[14]  M. R. Carter,et al.  Conservation tillage in the Corn Belt of the United States. , 1994 .

[15]  A. Metson.  Methods of Chemical Analysis for Soil Survey Samples , 1957 .

[16]  M. Batty,et al.  Spatial Analysis: Modelling in a GIS Environment , 1998 .

[17]  D. Mcgrath,et al.  Spatial distribution of soil organic carbon concentrations in grassland of Ireland , 2003 .

[18]  M. Wander,et al.  Tillage effects on soil organic carbon distribution and storage in a silt loam soil in Illinois , 1999 .

[19]  Olle Selinus,et al.  Statistical analyses for heavy metal contents in till and root samples in an area of southeastern Sweden , 1998 .

[20]  K. Paustian,et al.  Spatial variability of soil organic carbon in grasslands: implications for detecting change at different scales. , 2002, Environmental pollution.

[21]  Jean-Luc Chotte,et al.  Spatial and temporal changes of soil C after establishment of a pasture on a long-term cultivated vertisol (Martinique). , 2000 .

[22]  J. Herrick,et al.  Soil carbon dynamics and potential carbon sequestration by rangelands. , 2002, Environmental pollution.

[23]  Rattan Lal,et al.  Managing U.S. cropland to sequester carbon in soil , 1999 .

[24]  Spatial structures of cobalt, lead, and zinc contents in tills in southeastern Sweden , 2000 .

[25]  Rattan Lal,et al.  Carbon sequestration in soils , 1999 .

[26]  D. Angers,et al.  Dynamics of Soil Organic Matter and Corn Residues Affected by Tillage Practices , 1995 .

[27]  R. Voroney,et al.  Tillage effects on the dynamics of total and corn-residue-derived soil organic matter in two southern Ontario soils , 1999 .