Submitted to: Soil Science Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: November 9, 2000
Publication Date: N/A
Technical Abstract: Land application of animal manure using site-specific techniques offers potential to optimize organic matter and nutrient utilization and reduce negative environmental impacts. The objective of this research was to characterize the spatial relationships of soil C, N, and P in two pastures in northwestern Arkansas having contrasting management intensities. The Cellar Ridge site was a lightly-grazed, 6-ha tall fescue (Festuca arundinacea Schreb.) pasture with limited previous manure application. The Benton site was an intensely-grazed, 9.5-ha bermudagrass (Cynodon dactylon) pasture with annual poultry litter application. Both sites were sampled on a 30 m grid with 0-15 cm soil cores collected and analyzed for C and N (combustion method) and P (Mehlich 3 extract). Mean values of C, N, and P were 2.34%, 0.18%, and 32.2 mg/kg and 1.67%, 0.17%, and 320 mg/kg for the Cellar Ridge and Benton sites respectively. Soil P observations were spatially correlated over approximately 3 lag distances at the Benton site but were spatially independent at Cellar Ridge. Both C and N showed no spatial dependence at the Benton site but were spatially dependent up to 3 lag distances at Cellar Ridge. Results indicate that both pasture systems had highly spatially-variable patterns of soil C, N, and P that would make site-specific application techniques difficult to apply.