Water Analysis Data Interpretation for Fruit Growers

1. FRUIT GROWERS LABORATORY, INC. Darrell H. Nelson Horticulturalist

2. 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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4. 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

5. 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

6. Irrigation Suitability Analysis

7. Plugging Hazards

8. 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

9. The Basic Constituents of an Irrigation Analysis Report…A Break Down

10. These are the major positively charged ions in irrigation water Cations Percent Base Sat

11. These are the predominately found negative ions in irrigation water Meq of cations = Meq of anions Anions Next prop to look at is pH

12. Micronutrients • These are plant micronutrients that may or may not be available Next prop to look at is pH

13. Crop Suitability and Amendments -

14. Water Pathogens • E. Coli 157 – Bacteria derived from fecal contamination • Salmonella – Primarily found in surface water • Listeria – Primarily found in refrigerated conditions

15. 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 1 of 3

16. 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 2 of 3

17. 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 3 of 3

18. Adjusting the soil pH changes more than just the pH ____________________________ Another ? on Micros

19. The Real Benefit of Water Data • Better crop selection • Better salinity management • Improved economic yields

20. Questions? For more info: Darrell H. Nelson www.fglinc.com Fruit Growers Laboratory, Inc.