Insights & Conclusions
The 'leaching fraction' of irrigation water moves through the soil, dispersing potentially harmful ions away from the root zone. A concern is the continuing increase in salinity of the groundwater, a not uncommon problem in areas plagued by poor groundwater quality. High salinity in irrigation water would impact the leaching process.
We believe that without 6 to 10 inches of effective rainfall or fresh water winter irrigation for efficient leaching every one to two years the use of 4.5 to 6 dS/m EC irrigation water may not be sustainable.
Boron in irrigation water may be adsorbed by particles in the soil matrix, and thus inaccessible to uptake by plant roots. However, we believe that adsorption sites can become saturated over time, with the result of a potentially harmful buildup of boron in the soil-water.