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

Percent Base Sat

Cations

• These are the major positively charged ions in irrigation water

Next prop to look at is pH

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

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.