Soil Ammonium Diffusion Constraints Contribute to Large Differences in Nitrogen Supply to Rice in the Southern United States Academic Article uri icon


  • This study was to determine if diffusion of soil ammonium may explain why many sandy soils have greater nitrogen (N)-supplying capacity to rice than clay soils. A laboratory procedure using transient-state methods measured the linear movement of soil ammonium (NH 4) in tubes packed with five field soils under aerobic conditions. Ammonium diffusion was measured by sectioning tubes after 48 h of equilibration and then measuring NH 4 by steam distillation. Effective diffusion coefficients, De, and NH 4 diffusion distance, d, per day ranged from De = 4.6 10 -5 cm 2 d -1 and 1.5 cm d -1 for Katy sandy loam to D e = 2.9 10 -7 cm 2 d +1 and 0.11 cm d -1 for League clay. Ammonium diffusion distance d was strongly related to soil clay content and hence was predicted by d = Y {[100/(% clay)] - 1}, where Y is set to 0.1. Predicted d and measured d were highly related (R 2 = 0.99). Taylor & Francis Group, LLC.

published proceedings


author list (cited authors)

  • Trostle, C. L., Tarpley, L., Turner, F., & Dou, F.

citation count

  • 2

complete list of authors

  • Trostle, Calvin L||Tarpley, Lee||Turner, Fred||Dou, Fugen

publication date

  • August 2011