Specific ion toxicity can be of concern. Use of chlorine for disinfection and muriate of potash for potassium fertilization can accelerate the build up of chloride. Use of composted wastes or manure in soil mixes can contribute sodium and chloride in addition to nutrients. Reclaimed water can have elevated levels of sodium and chloride. Boron can also be elevated in incoming water and should ideally be kept below 0.6 ppm.
Plants exhibit a wide range of tolerance to salinity and specific ions.
Growers take advantage of this by grouping plant material in the nursery according to relative salt tolerance. Sensitive plants including liners, azaleas, camellias, ferns and many deciduous plants are located in a portion of the nursery which does not utilize recycled water. Annual color or herbaceous crops along with many common ornamentals have a moderate level of salt tolerance once established and can be grown with water of moderate salinity. Some crops are very salt tolerant and can be irrigated with non-blended runoff. Where sodium and chloride toxicity is of concern, development of leaf burn can be minimized by utilizing drip-irrigation or by irrigating at night to reduce foliar deposition of salts.