Wednesday, November 15, 2006

Soil Carbon Changes due to Management Changes in a Semi-Arid Environment.

Gayatri Yellajosula, North Dakota State University, P.O Box 5638, Fargo, ND 58105 and Larry Cihacek, NDSU-Soil Science Dept., PO Box 5638, Fargo, ND 58105-5638.

Carbon (C) sequestration by soil is influenced by changes in soil and land management.  We examined the effects of changes in soil and land management on the quantity of C stored in the surface 60 cm of soil in a semi-arid region of southwestern North Dakota. Two adjacent blocks of land on similar soil types were sampled for C in the fall of 1999 and again in the summer of 2004.  One block of land was continuously cropped for more than 50 years while the other block of land was in continuous native rangeland.  The rangeland was tilled in the fall of 1999 with native rangeland control strips left untilled for comparison.  On both blocks of land, strip plots were established with restored grass either grazed or left ungrazed or cropped to hard red spring wheat, barley or oat under conventional crop-fallow or continuous no-till. Comparisons of changes between the two sampling dates indicated that significant losses in soil C were still occurring in the disturbed rangeland even when restored to grass.  Management implications related to environmental conditions will be discussed.