Agriculture can change the hydrologic balance of a landscape either through a change from native vegetation or the addition of water by irrigation or both. Since salts move with water, a change in hydrology will mean a change in the salt balance which may cause land and water degradation. The basic principles of water and salt movement can be applied to cotton growing areas to identify potential salinity hazards both on the fann and in the catchment Salinity problems are due to the presence of a high concentration of salts in soils or waters. A sodicity problem occurs where there is a high proportion of sodium compared to other ions resulting in degraded soil.