Monday, November 13, 2006 - 11:15 AM

Effect of Grinding on Soil Carbon Analysis.

Larry Cihacek and Keith Jacobson. NDSU, Soil Science Dept, PO Box 5638, Fargo, ND 58105-5638

Little reference is made in the literature about the effects of soil grinding on C analysis by high temperature combustion.  Five soils with a range in texture, and organic matter content were ground to pass a 2-mm, 1-mm, 0.5-mm, 0.25-mm and 0.15-mm sieves.  Three soils were noncalcareous and two soils were calcareous.  Six replicates of each grinding fineness of each soil were analyzed by high temperature combustion and inorganic C was determined by release upon acidification.  Decreasing the ground particle size from 2-mm to 0.15-mm decreased the sample standard deviation from two-fold to six-fold.  No significant difference between grinding fineness was observed for three of the soils but significant differences were observed for two of the soils with the coarser particle sizes.  The differences appeared to be for soils where the greatest diversity was observed in textural separates.