Author(s)

R. Al-Soufi

Abstract

In clay soil the massive network of cracks in the upper part of soil profile is in a dynamic process of evolution and collapsing due to the alternative processes of drying and wetting in summer time, and in some places, freezing and thawing in winter time. Water moves by gravity only in cracks of the soil and other minuets interstitial system and can transport water and chemicals at velocities much faster than predicted with the conventional solute transport models. A method has been developed to calculate that part of rainwater, which bypasses directly through the macropores to the drains and does not react with soil solu- tion or with the soil solid particles. Drain flow records, surface runoff, evapo- transpiration and rainfall measurements over a considerable period of time, have been used in o

Keywords