As irrigation supplies from the Rio Grande diminish and as growers turn to wells to keep their orchards going, the quality of well water becomes a major concern. Often, however, we are more concerned with the quality of the water than we are with the effect of such water on the soil and, by extension, the effect of the soil on the tree.
Citrus is relatively intolerant of saline conditions.
Rootstock does make a difference, i.e., Cleo is more salt tolerant than sour, which is more tolerant than trifoliate and many of its hybrids. Similar results have been reported in California. Research in Texas has shown that citrus can survive and grow with irrigation water having salinity levels that are classified as very high, i.e., greater than 2250 ppm, provided that the sodium content is not over 60 percent of the total salts, that the sodium absorption ratio is below 18, that boron is less than 1.0 ppm and that proper irrigation amounts and frequency are carried out on soils that are deep and have good internal drainage. The more important issue is that of soil salinity. Trouble starts when soil salinity in the root zone exceeds about 2600 ppm.