Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: April 2, 2002
Publication Date: November 10, 2002
Citation: Zobeck, T.M., Van Pelt, R.S., Acosta Martinez, V.,Bronson, K.F., and Upchurch, D.R. 2002. Sampling protocol and variation of field soil carbon. 2002 Annual Meeting Abstracts ASA/CSSA/SSSA CD paper s05-zobeck171145 Poster.PDF Technical Abstract: Previous studies have evaluated the amount of soil organic carbon (SOC) for grassland and cropped loamy soils but little data is available for sandy, semi arid, thermic soils. In this project we determine the level of SOC that can be maintained by cropland, conservation grassland and native grassland in five sandy soils of the semi arid and thermic Southern High Plains of Texas (SHP). The soils were sampled using a specially designed closed sampling chamber to allow calculation of bulk density while sampling at depths 0 5, 5 10, 10 15, 15 30, and 30 60 cm. Native rangeland (NR) and conservation reserve grassland (CG) were compared with nearby cropland (CL) in cotton, wheat, wheat and cotton in rotation, sunflowers, black eyed peas, and a high residue forage. SOC differences with depth were only found in the native rangeland sites with the surface layer having about 40 60 % more SOC than the other layers. Significant differences in SOC for the surface layer were in the order NR>CG>CL. In most other depth layers, the NR was greater than the CG and CL, which were the same. Overall, significant decreases in SOC were observed by surface texture in the order loam>fine sandy loam>loamy fine sand = fine sand.