Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 1, 1995
Publication Date: N/A
Technical Abstract: Field observations have shown that macropores disrupted by tillage may continue to act as preferential flow paths for water and chemicals in some cases but not in others. Laboratory and modelling studies were conducted to investigate conditions under which a buried macropore might act as a preferential flow path. Uniformly-packed soil columns and layered soil columns with a dense soil layer underlying a looser surface were studied. In a uniform soil neither the laboratory study nor the model predictions indicated flow into a buried macropore. For a layered system, flow into the macropore was predicted from model simulations but no macropore flow was observed from the laboratory columns, indicating possible reabsorption of water and Bromide along the wall of the macropore. Model simulations predicted no macropore flow in a uniform soil even with long rainfall or ponded surface conditions. All simulations for the layered system predicted dmacropore flow with the greatest movement of water and Bromide into the macropore occurring with ponding on the soil surface.