By Walter S. Phillips from Homer L. Shantz' records and negatives. / Contract: Office of Naval Research / Nonr-2173 (01) / Project NR 387-018

Research on soil organic carbon (SOC) within the northern Great Plains has not been clearly documented. Objectives of this study were (i) to inventory literature reporting SOC responses to agroecosystem management, (ii) extract data for the Northern Great Plains Rapid Carbon Assessment, and (iii) summarize data to identify relationships between SOC and land use management. Soil organic carbon at 0 ? 15 cm depth was 1.57 ? 6.87 kg C m-2, 1.56 ? 5.34 kg C m-2, and 1.48 ? 5.48 kg C m-2 under grasslands, conservation tillage (CST), and conventional tillage (CT), respectively. Soils with a Productivity Index (PI) of 80 ? 100 had greater mean SOC (4.14 kg C m-2) across all managements. Correlation between SOC and PI for CT was significant (r=0.240) (P=0.05) and highly significant (r=0.418) (P=0.01) for CST. Management practices for cropland soils combined with productivity potential appear to relate to the C accrual potential of northern Great Plains soils.