Throughout the United States, many state and local governments place restrictions on the use of potable water for irrigating turfgrass landscapes. For many golf course superintendents, use of reclaimed, or other secondary water sources is the now the norm. Unfortunately, much of the recycled water used for irrigation contains high concentrations of dissolved salts that are potentially toxic to turfgrasses. More importantly, the use of effluent or reclaimed water sources often precedes the loss of soil structure resulting from the effects of high levels of sodium, bicarbonate and carbonate salts.
PhAcid Injectable Irrigation and Soil Water Acidifer
Sodium Affected Soils
Sodium exists in nearly all irrigation water. High concentrations of sodium in irrigation water can be detrimental to both turf and soils. If water with levels of sodium that exceed 70 ppm (>70 mg/L) and low calcium and magnesium is applied frequently to clay soils, the sodium will tend to displace calcium and magnesium on clay particles. As the amount of exchangeable sodium in a soil increases, clay particles become increasingly unstable, leading to a disruption of the soil structure.
Problems with Bicarbonates and Carbonates
Of all the mineral constituents in irrigation water, bicarbonates and to a less extent carbonates are often underestimated in terms of their potential to synergize soil degradation and disrupt water movement through soils.
Carbonates greatly complicate the management of excessive Na. Their reactions reduce the amount of free calcium and magnesium in soil, allowing sodium to displace calcium from the negatively-charged exchange sites on clay particles. As the amount of exchangeable sodium in a soil increases, clay particles become unstable, leading to a disruption of the soil structure (deflocculation) and blocking of pores of a soil.
Today, many soil scientists recognize that poor water penetration is directly caused by a chemical imbalance in the soil and irrigation water. Their recommendations now suggest that many cases involving soil deterioration should be addressed by first amending the irrigation water or treating soils with amended water in an effort to reduce the carbonate threat in irrigation water and in soils.
This order of correction does not imply that soil amendments be abandoned. However, since the problem of sodium affected soils goes beyond correcting abnormal carbonate levels, using soil amendments containing calcium is usually required.
We strongly recommend that water and soil samples be taken and analyzed on a routine basis in order to develop and maintain a comprehensive management plan to correct sodium-affected soils.
Any soil receiving irrigation water with high sodium (Na) and bicarbonate levels should be amended with a soluble source of calcium in addition to the pHAcid spray program. In addition, irrigation water high in bicarbonates (> 1.5 – 2.0 meq/L (bicarbonate level = 90 – 120 ppm) should be amended with the pHAcid irrigation treatment schedule.
pHAcid Sprayable application program: 32 to 64 ounces per acre in a 1 to 2 gallon spray solution per 1000 sq. ft. (1-2 liters per 100 sq. meter). Apply sufficient water to move product into the soil profile.
pHAcid Injectable irrigation water program:
Inject pHAcid at the rate of 1 gallon per 20,000 gallons of applied water every month if the RSC index of source water is more than 150 ppm (> 1.50 meq/L ).
Inject pHAcid at the rate of 1 gallon (4 liters) per 20,000 gallons (80,000 liters) of applied water every two weeks if the RSC index of source water is more than 250 ppm (> 2.5 meq/L ).
pHAcid treatments (in combination with soluble sources of calcium if needed) should be continued until sodium-affected soil levels are below hazardous levels.
A good seasonal and annual monitoring program is recommended.