Salinity and Grape Irrigation

1
Ca Na
Cl- SO4
NO3-
Water Test Interpretation
Mike Kizer OSU Extension Irrigation Specialist
HCO3- CO3
K Mg
2
Measures of Water Quality

• Electrical Conductivity (EC)
• Total Dissolved Solids (TDS)
• Individual mineral concentrations
• Calculated salinity products (Hardness, SAR,
  Na, etc.)

3
Electrical Conductivity(EC)

• Pure water will not conduct electric current
• The more minerals dissolved in water, the more
  current it conducts
• EC is a good estimator of total mineral content
  (TSS)

4
Units - EC

• mmho/cm (millimho per centimeter)
• mmho/cm (micromho per centimeter)
• dS/m (deciSiemen/meter)
• mS/cm (milliSiemen per centimeter)
• 1 mmho/cm 1 dS/m 1mS/cm
• 1 mmho/cm 1000 mmho/cm

5
Total Dissolved Solids(TDS)

• TDS is calculated by adding all measured mineral
  concentrations as determined by chemical analyses
• TSS is an estimate of TDS based on EC
• EC (mmho/cm) x 640 ? TSS mg/l
• This equivalence is approximate and depends on
  the ions causing the salinity (High levels of
  CO3 and HCO3 affect the ratio)

6
Units - TDS / TSS

• mg/l milligrams/liter ppm parts
  per million
• mg/l micrograms/liter ppb parts per
  billion
• 1 mg/l 1 ppm in water chemistry (1 liter
  of water weighs 1,000,000 mg)
• 1 mg/l 1000 mg /l
• 1 mg /l 1 ppb in water chemistry

7
SWFAL Water Quality Tests

• The OSU Soil Water Forage Analytical
  Laboratory (Room 048 Ag. Hall) offers three water
  tests
• Livestock Water Test
• Household Water Test
• Irrigation Water Test
• (All tests require a 1 pint water sample)

8
Livestock Water Test

• Price 6.00
• Analytes
• pH
• Total Soluble Salts (TSS)
• Electrical Conductivity (EC)
• Nitrate-Nitrogen (NO3-N)

9
Livestock Water QualityTotal Soluble Salts - TSS

• TSS (ppm) Interpretation
• lt 1000 Excellent
• 1000 3000 Satisfactory for all animals
• 3000 5000 Unsatisfactory for poultry
• 5000 7000 Can be used except for pregnant,
  lactating or immature livestock
• 10,000 Unsatisfactory for all animals

10
Livestock Water QualityNitrate- Nitrogen NO3-N

• NO3-N (ppm) Interpretation
• lt 100 Satisfactory for all animals
• 100 290 Use with care when given in
  combination with high nitrate feeds
  (especially forages in times of drought)
• 290 Unsatisfactory for all animals

11
Livestock Water Quality

• Sulfate (SO4) If most of the soluble salts
  are sulfates the acceptable TSS levels
  are reduced
• pH The preferred range is 6.0-8.5. Animals
  can tolerate water outside this range.

12
Household Water Test

• Price 10.00
• Analytes
• Sodium (Na) ? Chloride (Cl)
• Calcium (Ca) ? Sulfate (SO4)
• Magnesium (Mg) ? Nitrate-Nitrogen (NO3-N)
• Potassium (K) ? Electrical Conductivity (EC)
• pH ? Total soluble Salts (TSS)
• Hardness

13
Household Water TestNitrate-Nitrogen (NO3-N)

• NO3-N is the only analyte on the test with a
  Federal SDWA Standard
• The NO3-N standard is 10 mg/l
• Newborn infants (less than 9 months) and pregnant
  women are at-risk consumers
• NO3-N affects the bloods ability to carry
  oxygen, causing methemoglobenemia

14
Household Water TestSecondary Contaminants

• Other regulated analytes on the Household Water
  Test are Secondary Contaminants that have Federal
  SDWA Guidelines
• Exceeding SDWA Guidelines is not a primary health
  risk
• Secondary contaminants affect aesthetic quality
  of water (taste, odor, etc.) or damage the water
  system (hardness, corrosion, etc.)

15
Household Water TestSecondary Contaminants

• Secondary contaminants can indirectly affect
  health
• High sulfates can cause diarrhea which could
  result in dehydration
• Corrosion due to low pH can leach lead from
  plumbing fixtures which could cause lead toxicity

16
Corrosiveness of WaterpH Alkalinity Balance
17
Household Water TestHardness
Hardness is caused by calcium and magnesium
(iron also contributes to hardness)
Hardness Class CaCO3 Equivalent Hardness (mg/l)
Soft 0 60
Moderately Hard 60 120
Hard 120 180
Very Hard 180
18
(No Transcript)
19
Irrigation Water Test

• Price 12.00
• Analytes
• Sodium (Na) Chloride (Cl)
• Calcium (Ca) Sulfate (SO4)
• Magnesium (Mg) Nitrate-Nitrogen (NO3-N)
• Potassium (K) Carbonate (CO3)
• Boron (B) Bicarbonate (HCO3)
• pH Electrical Conductivity (EC)
• Hardness Total Soluble Salts (TSS)
• Residual Carbonates Sodium Adsorption Ratio
  (SAR)

20
Irrigation Water Quality Important Analytes

• EC (or TSS) determines soil osmotic potential
  
• SAR (or Na) rates infiltration problem
  potential
• Boron toxic at very low concentrations
• Residual Carbonates (RSC) raises effective
  SAR/Na

21
The Effect of Salinity of Soil Water Availability
Salt Concentrations 0.4 4000 mg/l 0.2
2000 mg/l 0.1 1000 mg/l
22
Irrigation Water QualitySodium (Na) Hazard

• Na generally creates soil infiltration problems
  before becoming toxic to plants
• In hot, dry weather conditions sprinkling can
  lead to leaf burning due to Na toxicity
• Na reduces soil permeability by dispersing clay
  particles which seal larger pore spaces
• Na hazard is greater high clay content soils
• Na hazard is greater in expanding clays than in
  non-expanding clays

23
Infiltration Problem Potential From High Na Water
EC 1305 mmho/cm SAR 19.0
EC 1769 mmho/cm SAR 8.5
24
Irrigation Water QualityBoron (B)

• Crops are very sensitive to boron
• Threshold soil concentration for yield reduction
  0.3 10 mg/l
• Toxic to all vegetation ?30 mg/l
• Typical Boron toxicity symptoms are spotting,
  yellowing and/or drying at tips and edges of
  older leaves

25
Irrigation Water QualityResidual Carbonates (RSC)

• Excessive residual bicarbonate and carbonate in
  irrigation water will combine with Ca and Mg ions
  in soil
• This effectively increases the SAR and leads to
  greater risk of infiltration problems
• RSC (CO3 HCO3) - (Ca Mg)

26
(No Transcript)
27
Salinity Units and Terms(Electrical Conductivity)
1 mmho/cm 1 dS/m 1 mmho/m 1000
mmho/cm 1 dS/m 1 mS/cm EC electrical
conductivity of water ECe electrical
conductivity of saturated extract
28
Water Quality Units and Terms(Concentrations)
1 mg/l 1 ppm 1 mg/l 1000 mg/l 1mg/l
1 ppb TSS Total Soluble Salts TDS Total
Dissolved Solids TSS ? TDS TSS, (mg/l) ? 640 x
EC, (mmho/cm)
29
Water Quality Units and Terms(Concentrations)
meq/l milliequivalents per liter epm
equivalents per million 1 meq/l 1 epm Ion ppm
per meq/l Ion ppm per meq/l Ca 20 CO3
30 Mg 12 HCO3
61 Na 23 SO4 48 K
39 Cl 35.5
30
Derived Water Quality Terms
SAR Sodium Adsorption Ratio SAR Na
(CaMg)/2 Na Sodium Percentage Na (Na x
100) (CaMgKNa) RSC Residual Sodium
Carbonates RSC (CO3 HCO3) - (Ca Mg) (the
3 calculations on this page are in meq/l)