Chapter 15

Water Quality for Irrigating Vineyards

Specific Ions

Specific ions can be toxic to plants and/or detrimental to the soil’s physical structure. Certain ions (sodium, chloride, and boron) can cause direct root injury, accumulate in shoot tissues and cause shoot toxicity problems, or cause direct foliar toxicity on plant leaves. These problems are almost always present when total salinity is high. Tolerances vary among grapevine varieties and rootstocks.


Although chloride is essential to vines in very low amounts, it can cause toxicity to sensitive grapevines at high concentrations. Excess chloride may lead to leaf injury in grapevines and a resultant reduction in vine performance.


Grapevines are also quite sensitive to boron. Boron injury is typically drying, yellowing and spotting along the tips and edges of older leaves.


Iron (Fe) may be present in a soluble (ferrous) form, which may create emitter clogging problems at concentrations as low as 0.1 ppm.


Manganese occurs in groundwater less commonly than iron and generally in smaller amounts. Like iron, manganese in solution may precipitate out as a result of chemical or biological activity, forming sediment that clogs emitters and other system components.


Nitrogen in irrigation water is largely a fertility issue, and nitrate (NO3¯) can be a significant nitrogen. The nitrate ion often occurs at higher concentrations than ammonium in irrigation water.

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