Deep drainage varies considerably depending on soil properties and irrigation management, and is not necessarily ‘very small’ - 50-100 mm/yr is typical, though 0 to 900 mm/yr has been observed.

Vertosols, are a heavy clay soil that cover a large part of the world, and are used extensively for irrigated agriculture.

The overall objective is to develop soil and agronomic management techniques to improve the aeration of irrigated clays and hence their productivity for cotton.

This project was aimed at providing a rational approach to restoring soil structure after it becomes degraded under intensive irrigated cotton production. The specific aims were: 1.