FRUIT GROWERS LABORATORY, INC.
Darrell H. Nelson
Horticulturalist
Did You Know?
• California Farm Gate value in 2009
–
≈ 36 – 37 billion dollars
–
90% comes from products produced on
irrigated lands
–
California does not have a water problem,
it has a salt problem
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Talking Points For
Interpreting Irrigation Analysis Data
• Why such a complete analysis?
• Critical elements
• Basic parts of an irrigation water analysis
• Interpreting your irrigation analysis data
• Water-born pathogens
• Soil-Plant-Water interrelations
• Units and conversions (see handout)
First
Why Such A Complete Analysis?
• To make sure the data is valid
• To make sure every critical element is examined
• To check cations and anions are in balance
• To check that electrical conductivity and total
dissolved solids correlate
– TDS x 0.7(conversion) = approximate E.C.
Closer look at soil N avail
Irrigation Suitability Analysis
Plugging Hazards
Critical Elements
• Chloride – Specific ion toxicity
• Boron – Specific ion toxicity
• Sodium – Should be less than 60 % of cations
• Bicarbonate – High bicarbonate water seals the soil
• Carbonate – Waters containing carbonate must have a pH > 8.3
and are usually very pure
• E.C. – Should be less than 1200 umhos/cm for salt sensitive
crops
• SAR (Sodium Absorption Ratio) – Severe problems will persist
above 9
The Basic Constituents of
an Irrigation Analysis
Report…A Break Down
Cations
• These are the major positively charged
ions in irrigation water
Percent Base Sat
Anions
• These are the predominately found
negative ions in irrigation water
• Meq of cations = Meq of anions
Next prop to look at is pH
Micronutrients
• These are plant micronutrients that may or may
not be available
Next prop to look at is pH
Crop Suitability and Amendments
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Water Pathogens
• E. Coli 157 – Bacteria derived from fecal
contamination
• Salmonella – Primarily found in surface water
• Listeria – Primarily found in refrigerated
conditions
Soil-Water-Plant Interrelations
• A sickly plant growing in a well drained and well fertilized
soil is likely to be struggling with a pathogen or a
physical disorder
• High soil Potassium promotes Magnesium deficiencies in
plants
• High Magnesium soils usually have low infiltration rates
• High soil Phosphorus levels promotes low plant uptake
of Iron, Zinc, Manganese, and Copper
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Soil-Water-Plant Interrelations
• Soil pH will eventually be nearly the same as the
irrigation water pH
• Soil E.C.e should be 1.5 to 2 times the water
EC. If higher, check soil drainage and/or
leaching conditions
• At an E.C.e above 8, the soils osmotic pressure
will be too high and plants will be stressed
• At a higher E.C.e the soil solution may extract
water from the plant or the fruit
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Soil-Water-Plant Interrelations
• As soil texture becomes heavier, water and nutrient
holding capacity increases
• As soil texture becomes heavier, the availability of water
and nutrients decreases
• As soil pH changes nutrient availability also changes
(see pH chart)
• Hard water makes soft soil
• Soft water makes hard soil
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Adjusting the soil pH changes more than just the pH
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Another ? on Micros
The Real Benefit of Water Data
• Better crop selection
• Better salinity management
• Improved economic yields
Questions?
For more info:
Darrell H. Nelson
www.fglinc.com
Fruit Growers Laboratory, Inc.