Greenhouse and High Tunnel Workshop -- Mountain Grove, MO 8/4/2016

If you take care of Fertigation and your soil, the soil will Fertilizer Proportioning take care of your plants.

5% by O.M. Bob Schultheis Natural Resource Engineering Specialist / CPD 25% Water 45% Mineral Special thanks to David Trinklein, Division of Plant Sciences, Matter University of Missouri, for parts of this presentation 25% Air Greenhouse and High Tunnel Workshop Mountain Grove, MO 50% pore space 50% solid August 4, 2016 1

Plant Nutrition vs. Plant Fertilization Why do we still have problems?

Nutrition: Fertilization: • Focus has been on solving problems Availability and type Adding nutrients to – Delay crops of chemical growing medium – Reduce quality elements in plant in proper amounts – Lower profits

“Need to focus on preventing problems”

What is Fertigation? Fertigation • Advantages • Fertilizer + Irrigation = Fertigation – Relatively uniform fertilizer applications • Nutrient “spoon feeding” – Flexibility in timing of applications • Can be done by: – Less fertilizers used – hand – Reduced costs – sprinkler system • Disadvantages – – drip irrigation system Potential contamination hazard from equipment malfunctions – Backflow prevention devices required – Careful handling of liquid fertilizers

1 Greenhouse and High Tunnel Workshop -- Mountain Grove, MO 8/4/2016

Objectives of Fertigation Nutrition Affected By • Maximize profit by applying the right • Chemical considerations amount of water and fertilizer – pH ‐ water, fertilizer solution • Minimize adverse environmental effects – Alkalinity ‐ water, fertilizer solution by reducing leaching of fertilizers and – EC ‐ water, fertilizer solution other chemicals • Fertilizer analysis – Macronutrients, micronutrients • Non‐nutritional elements – possible toxicities – Na, Cl, F, Al

pH pH 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 • pH affects the solubility of fertilizers and the Influence of pH Nitrogen efficacy of pesticides and growth regulators on nutrient Potassium – The higher the water pH the less soluble these Phosphorus availability* Calcium materials are Magnesium

Iron

Manganese

Boron *based on a soilless substrate containing sphagnum peat moss, Zinc composted pine bark, vermiculite, and sand Copper 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0

Reference: www.ces.ncsu.edu/depts/hort/hil//hil‐558.html

Problems Associated With pH Adjustment Improper pH Low pH High pH • Raise pH • Toxic: • Deficient: –Use fertilizer with lower acid residue – Iron – Iron . ammonium vs. nitrate – Manganese – Manganese . calcium compounds – Zinc – Zinc – Copper – Copper – Apply limestone

• Deficient – Boron . calcitic ‐‐ CaCO3 – Calcium . dolomitic ‐‐ CaMg(CO3)2 – Magnesium . hydrated ‐‐ Ca(OH) • Sensitive 2 – Ammonium‐N

2 Greenhouse and High Tunnel Workshop -- Mountain Grove, MO 8/4/2016

pH Adjustment

• Lower pH –Use fertilizer with acid residue – Apply sulfur‐containing compounds + ‐2 S + O2 + H2O H2SO4 2 H + SO4 (requires action of microbes) –Sulfuric acid

Conclusions

• pH greatly affects plant nutrition • Soilless media prone to pH changes • Many factors influence pH change • Monitoring pH important – Adjust according to crop and need

Nutrition Affected By Alkalinity

• Chemical considerations • Alkalinity establishes the buffering – pH ‐ water, fertilizer solution capacity of water and affects how much – Alkalinity ‐ water, fertilizer solution acid is required to change the pH – EC ‐ water, fertilizer solution • Don’t confuse with alkaline pH • Fertilizer analysis – Macronutrients, micronutrients • Non‐nutritional elements – possible toxicities – Na, Cl, F, Al

Reference: www.ces.ncsu.edu/depts/hort/hil//hil‐558.html

3 Greenhouse and High Tunnel Workshop -- Mountain Grove, MO 8/4/2016

Influence of alkalinity Water Source Quality on acidifying water Good • Well = check pH & hardness • Municipal = may be expensive • Spring = may not be dependable • River or stream = depends on runoff

pH • Lake or pond water = sand filters

pHpH = 5.8 Poor • Pump to tank on hill = limited use Water oz. oz.

fl. fl.

68.6 15.8

20 Reference: www.ces.ncsu.edu/depts/hort/hil//hil‐558.html

Water Quality Analysis Plugging Potential of Drip Irrigation Systems • Inorganic solids = sand, silt • Organic solids = algae, bacteria, slime Moderate Severe Factor (ppm)* (ppm)* • <500 ppm) Dissolved solids ( Physical – Iron & Manganese Suspended solids 50-100 >100 – Sulfates & Chlorides Chemical pH** – 7.0-7.5 >7.5 Carbonates (calcium) Dissolved solids 500-2000 >2000 • pH (5.2‐6.8 preferred in greenhouses) Manganese 0.1-1.5 >1.5 Iron 0.1-1.5 >1.5 • Hardness (<150 ppm) Hardness*** 150-300 >300 Hydrogen sulfide • E. coli bacteria 0.5-2.0 >2.0 * ppm = mg/L ** pH is unitless *** Hardness: ppm = gpg x 17

Resources: 21 http://soilplantlab.missouri.edu/soil/water.aspx PVC Casing Steel Casing https://utextension.tennessee.edu/publications/Documents/SP740-B.pdf 22

Nutrition Affected By How do we actually get the fertilizer to our plants? • Chemical considerations – pH ‐ water, fertilizer solution – Alkalinity ‐ water, fertilizer solution – EC ‐ water, fertilizer solution • Fertilizer analysis – Macronutrients, micronutrients • Non‐nutritional elements – possible toxicities – Na, Cl, F, Al

4 Greenhouse and High Tunnel Workshop -- Mountain Grove, MO 8/4/2016

Application Options Substrate Incorporation • • Pre‐plant Separately – Ground limestone (Ca, for pH) – Substrate incorporation – Superphosphate (P) • Post‐plant – Trace elements – Top dress/incorporate – Slow release materials – Liquid feed • Package (Might use all three on one crop) – “Starter charge” ‐ liquid or granular

Fertilizer Types Slow Release Fertilizers • Granular – Super phosphate, gypsum + Extended release period • Slow (controlled) release + Fewer nutrients leached – Osmocote®, MagAmp® + Use instead of or with liquid feed • Water soluble + Form of automation – Excel®, Jack’s Classic® ‐ Release rate varies • Organic ‐ Affects salts measurement – Bloodmeal, alfalfa meal ‐ Hard to leach excess salts • Chelated – Sequestrene 330®

Slow Release‐‐Types Post‐plant (Liquid)

• Plastic encapsulated • Most commonly used – Osmocote® (analysis varies) • Constant feed (CLF) – 12‐week to 9‐month release – dilute concentration • Slowly soluble fertilizers – every watering – Mag‐Amp® • Periodic feed • Sulfur‐coated urea – more concentrated – Primarily for turf – intervals (e.g. weekly)

5 Greenhouse and High Tunnel Workshop -- Mountain Grove, MO 8/4/2016

Feeding Rates Nutritional Monitoring . Constant liquid feed • Visual inspection – 250 ppm N (top) – Too late – 150 ppm N (sub) – Symptoms = impaired growth . Periodic feeding • Check “vital signs” of plant – 500 ppm N weekly may Salt top dress with Osmocote® – pH and soluble salts . Bedding plants • Foliar (tissue) analysis – 150 ‐ 250 ppm N as needed – Once per crop (expensive)

Fertilizing Equipment It’s All About Balance of Elements

Ratio in Ratio in medium plants

How Injectors (Proportioners) Work Conversions

To get from ratios to percent: Injector Ratios (1/50) x 100 = 2% 1:50 = 2.0% To get from percent to ratios: 1:100 = 1.0% 100/2% = 1:50 1:200 = 0.5% 1:500 = 0.2% 1:1000 = 0.1% • Two types – Venturi (Hozon®, Syphonex®, EZ‐Flo®, Add‐It®, Young®) – Positive displacement (Dosatron®, DosMatic®, Anderson®, Smith®)

Reference: extension.uga.edu/publications/detail.cfm?number=B1237

6 Greenhouse and High Tunnel Workshop -- Mountain Grove, MO 8/4/2016

Venturi Proportioners Estimating Stock Tank Size

• Use pressure differences to draw Water flow • Gallon volume of square or rectangular tank stock solution into water line = Length x Width x Depth in feet x 7.5 • Pressure changes cause different – Example: uptake rate 6’ L x 4” W x 2.5’ D x 7.5 = 450 gallons • Must calibrate for local conditions – Water pressure • Gallon volume of round tank (approximate) – Hose length Suction = Diameter x Diameter x Depth in feet x 6 • Can require large stock tank Stock – Example: 2’ D x 2’ D x 3’ D x 6 = 72 gallons tank

Venturi Proportioner Examples Venturi Proportioner Examples • Hozon® • EZ‐Flo® – 1:16 ratio, 35 PSI minimum – 1:1000 to 1:100 variable ratio – Unit not more that 50’ from hose end (2/3 tsp/gal to 2 TBS/gal) – Backflow preventer included – 2 GPM min. flow rate – Do not use with drip irrigation system – Backflow preventer not included – http://hozon.com – http://ezfloinjection.com • Grow More® • Add‐It® – 1:16 ratio, 30‐90 PSI range – 1:200 ratio, 10‐80 PSI range – Unit not more that 75’ from hose end – Backflow preventer included – 0.5‐20 GPM min. flow rate – Do not use with drip irrigation system – Backflow preventer not included – http://www.groworganic.com/siphon‐mixer‐injector.html – http://fertilizerdispensers.com/services/add‐it.htm

Venturi Proportioner Examples Positive Displacement

• Young® • Flowing water drives piston that pumps stock – 1:30 to 1:200 variable ratio solution – 2 GPM min. flow rate – No electricity used – Backflow preventer not included • Rated with min. & max. flow rates depending – Very accurate on model – http://www.youngproductsinc.com/other_products.html • Not affected by pressure changes (within range)

7 Greenhouse and High Tunnel Workshop -- Mountain Grove, MO 8/4/2016

Dosatron® Positive Displacement Examples Intake water flow Blended solution • Dosatron® (variable) – 1:3000 to 1:4 ratios, 4.3‐85 PSI – 0.04‐14 GPM flow rate Pressure – Dosing proportional to water flow regulator – Operates without electricity, using water pressure as the power source Filter Mixing – http://www.dosatron.com chamber

Positive Displacement Examples Proportioner Installation • DosMatic® Backflow Valve – 1:4000 to 1:10 ratios, 3‐100 PSI By‐pass line for clear water – Dual lines preferable 0.4‐45 GPM flow rate P – Operates without electricity, using Backflow preventer water pressure as the power source Siphoning from stock tanks – http://hydrosystemsco.com/brands/volumetric‐brands/dosmatic/ • Anderson® – http://www.heanderson.com/products.php • Smith® – http://www.usgr.com/fertilization‐feeding‐injectors/smith‐ measuremix‐injector.php

Proportioner Calibration Checking Injector/Calculations

• Check frequently • Check accuracy with salts meter every • < 1:100 : volume uptake time new batch of stock is mixed EC vs volume output • Fertilizer companies supply tables P of EC values for each of their • Measure EC of output fertilizers at various concentrations solution • In‐line EC probe 20‐10‐20 peat‐lite special constantly monitors output • 200 ppm = EC of 1.30 • 250 ppm = EC of 1.63 • 300 ppm = EC of 1.95

Reference: http://www.4oakton.com/proddetail.asp?parent=2&prod=352&seq=2&Totrec=13

8 Greenhouse and High Tunnel Workshop -- Mountain Grove, MO 8/4/2016

Solubility of Selected Fertilizers Stock Mixing

Solubility of Fertilizer in Pure Water, lbs./gal. High quality, water soluble materials EC Ammonium nitrate 9.8 Mix in separate tank ‐ P Calcium nitrate 8.5 pump from another Potassium chloride 2.3 Best to use warm Potassium nitrate 1.1 water when mixing Hot • If two or more fertilizers are to be mixed in the stock ‐ increases H2O solubility NO3 Mix same solution, test their combined solubility by NH4 Tank first mixing them in 1‐5 gallons of water Use separate tanks for different fertilizers

Reference: http://extension.uga.edu/publications/detail.cfm?number=B1130

Stock Mixing Cautions Calculations -- ++ Ca & Mg vs SO & PO 4 4 -- To determine amount of fertilizer to add to • High concentrations make stock solution: (>100:1) can cause precipitates injector ratio (:1) desired ppm XX • Precipitates form % element 100 1.35 sludge in tank bottom • Use two injectors Ca SO = ounces fertilizer/gallon stock • Use dual head injector 4 Mg PO4

Calculations Calculations

How much fertilizer does one add to a 5 gallon How much fertilizer does one add to a 20 gallon bucket of stock to get 200 ppm N from a tank of stock to get 250 ppm N from a 21‐5‐19 20‐10‐20 fertilizer using a Hozon® injector (1:16)? fertilizer using a Smith® injector (1:100)?

16 200 100 250 X X 1.35 = X X 1.35 = 20 100 21 100 0.8 X 2.0 X 1.35 = 2.16 oz/gal 4.76 X 2.5 X 1.35 = 16.1 oz/gal 2.16 oz/gal X 5 gal = 10.8 oz in bucket 16.1 oz/gal X 20 gal = 322 oz 322 oz /16 oz per lb = 20.1 lbs fertilizer in tank

9 Greenhouse and High Tunnel Workshop -- Mountain Grove, MO 8/4/2016

Calculations Daily Operations

How much fertilizer do Bags? (25 lbs each) Which is easier,more 2 - 25 lb bags you add to a 50 gallon 55.5 / 25 = 2+ bags efficient and more Weigh out 5.5 lbs tank to get 200 ppm‐N Set up proportion: precise? from 3rd bag from a 15‐0‐15 55 lbs = 50 lbs 55.5 lbs in 50 gallons Fill tank to 50 gal. fertilizer using a 1:100 50 gal X gal injector? 2 - 25 lb bags 55X = 2500 50 lbs in 45.5 gallons? Fill tank to 45.5 gal. 2 bags + X = 45.45 gallons 45.5 gallons Less mess! No open bags! water

Fertigation Tips Fertigation Tips

• Get water supply tested (pH, alkalinity, TDS, etc.) • Regularly check suction tube filter in stock tank for • Use backflow preventer if required clogs and holes • Install the injector out of direct sunlight • Minimum injection duration of 45‐60 minutes is –Make sure stock tank is opaque and covered recommended • Install injector after the timer so tank does not stay • Maximum injection duration depends on soil type under constant pressure and nutrient and water requirements of the crop • Always drain unit if there is a chance of freezing –A “reasonable” maximum should not exceed 2 hours per zone • Be sure fertilizer is 100% water‐soluble – Make liquid concentrate first from water‐soluble powders – Strain concentrate to remove undissolved granules

Drip Irrigation Control Assembly Conclusion • Taking a plant from “seed to sale” involves proper fertilization • There are many ways to get the job done • The best way is the one that works consistently for you

10 Greenhouse and High Tunnel Workshop -- Mountain Grove, MO 8/4/2016

That’s a lot Questions??

to chew on! Robert A. (Bob) Schultheis Program Complaint Information Natural Resource Engineering Specialist To file a program complaint you may contact Webster County Extension Center any of the following: 800 S. Marshall St. Marshfield, MO 65706 University of Missouri Voice: 417-859-2044 . MU Extension AA/EEO Office Fax: 417-468-2086 109 F. Whitten Hall, Columbia, MO 65211 E-mail: [email protected] . MU Human Resources Office 130 Heinkel Bldg, Columbia, MO 65211 Web: extension.missouri.edu/webster USDA . Office of Civil Rights, Director Room 326-W, Whitten Building 14th and Independence Ave., SW Washington, DC 20250-9410

The University of Missouri does not discriminate on the basis of race, color, national origin, ancestry, religion, sex, sexual orientation, gender identity, gender expression, age, genetic information, disability, or protected veteran status.

62 61

11