Water Harvesting: Soil/Water Impacts of Salt Treatment

Abstract

The responses of mined -land and natural soil materials to additions of various salt solutions in irrigation water from water harvesting were evaluated by an experimental soil column study. A pilot water harvesting agrisystem on the Black Mesa in northeastern Arizona was the source of data and soil materials used in the study. A salt leaching simulation model provided predictions for comparison to the experimental results. In general, Na, Ca, and Mg were all easily leached from both soil materials, with higher concentrations yielded from the minespoil. When sodium was applied in solution, the minespoil accumulated 20% of the amount applied in the upper 10 cm of the soil column, while the natural soil retained 50% in the upper 25 cm. In addition, the natural soil retained 60% of the Ca applied in solution. The simulation model produced good results for Na but only fair prediction of Ca and Mg. A discussion of the experimental conclusions' applicability to field conditions, the difficulties of the salt leaching model, and recommendations for further research is given.