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United States Department of Agriculture

Agricultural Research Service

Research Project: Spatial Modeling of Agricultural Watersheds: Water and Nutrient Management and Targeted Conservation Effects at Field to Watershed Scales

Location: Agricultural Systems Research Unit

Title: Spatial patterns and cross-correlations of temporal changes in soil carbonates and surface elevation in a winter wheat-fallow cropping system

Authors
item Sherrod, Lucretia
item Erskine, Robert
item Green, Timothy

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 11, 2014
Publication Date: August 22, 2014
Citation: Sherrod, L.A., Erskine, R.H., Green, T.R. 2014. Spatial patterns and cross-correlations of temporal changes in soil carbonates and surface elevation in a winter wheat-fallow cropping system. Soil Science Society of America Journal. doi:10.2136/sssaj2014.05.0222.

Interpretive Summary: Soil erosion and deposition impact the sustainability of agricultural lands within the semi-arid Central Great Plains, USA. Temporal differences between high resolution digital elevation maps provide physical estimates of spatial erosion or deposition, and the depth to calcic horizon is a chemical indicator. We hypothesize that soil surface layer concentration of carbonates is inversely correlated with the change in surface elevation ('z). We studied a 109 ha field in northeastern Colorado under winter wheat-fallow rotations in alternating strips perpendicular to the prevailing wind. Soil samples (top 30 cm) were collected from 185 landscape positions in 2001 and in 2012. The change in carbonate concentration ('C) was significantly correlated with large-scale erosional and depositional areas (blocks) and with soil units, whereas 'z was correlated with management strips and blocks. Summit positions had the highest carbonate concentration, and toe-slope positions had the lowest. We found inverse relationships between 'z and 'C in summit and toe-slope positions at both erosional (>5cm) and depositional (<5 cm) areas, but 'z was not correlated significantly with 'C overall. A high-resolution map of 'z showed complex spatial patterns across scales, which inferred interactions between water and wind erosion and deposition, terrain and management.

Technical Abstract: Soil erosion and deposition impact the sustainability of agricultural lands within the semi-arid Central Great Plains, USA. Temporal differences between high resolution digital elevation maps provide physical estimates of spatial erosion or deposition, and the depth to calcic horizon is a chemical indicator. We hypothesize that soil surface layer carbonate concentration (CaCO3) is inversely correlated with the change in surface elevation ('z). We studied a 109 ha field in northeastern Colorado under winter wheat (Triticum aestivum)-fallow rotations in alternating strips perpendicular to the prevailing wind. Soil samples (top 30 cm) were collected from 185 landscape positions in 2001 and in 2012 and analyzed for CaCO3 using a modified pressure-calcimeter method. The change in CaCO3 ('C) was significantly correlated with large-scale erosional and depositional areas (west and east blocks, respectively) and with soil units, whereas 'z was correlated with management strips and blocks. The west block had an average 'C of 3.2 g kg-1 with 2.0 cm erosion, whereas the east block lost 4.4 g kg-1 with 4.2 cm deposition. Summit positions had the highest CaCO3, and toe-slope positions had the lowest. We found inverse relationships between 'z and 'C in summit and toe-slope positions at both erosional (>5cm) and depositional (<5 cm) areas, but 'z was not correlated significantly with 'C overall. High values of CaCO3 (>100 g kg-1) decreased over time. A high-resolution map of 'z showed complex spatial patterns across scales, which inferred both water and wind erosion and deposition, which were affected by terrain and management.

Last Modified: 9/21/2014
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