|Collins, Harold - Hal|
Submitted to: American Society of Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/26/2007
Publication Date: 10/30/2007
Citation: Collins, H.P., Pierce, F., Moore, A.D., Perry, E.M., Andrade-Sanchez, P., Alva, A.K. 2007. Conversion of Semi-Arid Shrub-Steppe Lands to Irrigated Crop Production: Spatial Variability of Soil Properties. American Society Agronomy Abstracts, 2007 International Meetings, New Orleans, LA, Nov 4-8, 2007, on CD, © Copyright 2007, ASA-CSSA-SSSA.I Interpretive Summary:
Technical Abstract: Converting native lands to irrigated crop production often requires land leveling to improve land suitability for farming operations. Our objective was to quantify how the conversion to irrigated cropland altered the spatial variability of surface soil properties in the Columbia Basin shrub-steppe lands of Eastern Washington. Prior to and after land leveling, an 8 ha site was mapped using RTK-GPS for elevation and with high resolution, airborne, multispectral imagery. Soil samples were obtained from the surface 30 cm from grid points arranged as an unaligned, regular grid at 12 m grid spacing. Additional sampling points were established at 1, 3 and 6 m distances in a random direction at approximately 10 % of the regular grid sites for the purpose of estimating short distance variance. Soil samples were analyzed for pH, Mehlich extractable nutrients, and soil C and N mineralization potential. After installation of the irrigation pivot, when the soil had been wetted to depth, soil electrical conductivity was mapped at two soil depths using the Veris Soil EC Mapping Systems. Wheat (Triticum aestivum L.) was grown on the site in 2007. Remote sensed imagery was obtained throughout the season and yield was mapped at harvest. Soil variability was changed by the land leveling operation but remnants of some pre disturbance features appeared in the EC maps and in the imagery of the bare soil and in the growing wheat crop. As expected, the land leveling operation greatly reduced soil C and N mineralization rates over those obtained from the native soil. Soil pH after disturbance increased an average 0.4 units and the spatial pattern of pH was greatly altered.