Media and Water Testing

Services provided by: UK Soils Laboratory Division of Regulatory Services Cooperative Extension Service College of Agriculture, Food and Environment Assistance with interpretation provided by departmental Extension faculty

Goal Support County Extension Agents in effectively and efficiently providing media and water analysis services to help clientele diagnosis problems and manage agricultural enterprises

Agenda Introduction of topic and background information Water testing form, bottle and sample handling and procedures Water test results and interpretation Soilless Media testing form and sample handling and procedures Media test results and interpretation Discussion of procedures in the County Office Pour-through method for a quick assessment Portable EC and pH meter Questions

Materials in your hand for this training Water Testing submission form with instructions Soilless Media Testing submission form with instructions HO 111, Understanding Irrigation Water Test Results and Their Implications HO 112, Understanding Soilless Media Test Results and Their Implications on Nursery and Greenhouse Crop Management

Why? When? … to test water or soilless media

Steps in the Process Sample is taken and form completed County sends completed form and sample to Regulatory Services, Soils Laboratory Soils Laboratory analyzes the sample s results back to county and to Horticulture and/or tobacco specialists Specialist adds comments/recommendations and s back to county and Soils Lab

Irrigation Water Testing Chemical Properties Only

Sampling and Handling From the source, not through irrigation system Run briefly before sampling Fill sample bottle and the pour down to ½- inch from top Tighten cap Store in refrigerator (briefly if necessary) Do not freeze Submit as soon as possible

Sampling and Handling From the source, not through irrigation system Run briefly before sampling Fill sample bottle and the pour down to ½- inch from top Tighten cap Store in refrigerator (briefly if necessary) Do not freeze Submit as soon as possible

Sample Submission Form

Report of Results

Irrigation Water Test Interpretation

Interpretative Publication HO-111 Understanding Irrigation Water Test Results and Their Implications on Nursery and Greenhouse Crop Management Dewayne L. Ingram, Professor Department of Horticulture

pH 5.5 to generally acceptable Less than potential problem and the elemental constituents of the water should be examined closely Greater than a possible problem, especially if there is high alkalinity; may interfere with the effectiveness of some pesticides and growth regulators when used as spray water

Electrical Conductivity (EC) Gage of the free ions in a solution Also referred to as dissolved/soluble salts Units of Measure: – milli-siemens/cm (mS/cm) = mmhos/cm – Reciprocal of Ohms (resistance) 1 dS/m = 1 mmhos/cm = 1 mS/cm

Source: Cavins, et al. Electrical Conductivity (EC)

Measure of soluble salts Less than no problem expected 0.75 to increasing concern of excessive accumulation of soluble salts over time Greater than expect severe problems

Measure of the buffering capacity of water Mostly CO 3 −2 and HCO 3 − Associated with Ca 2+ and Mg 2+ High alkalinity - same effect as limestone addition May cause rise in substrate pH over time Notice the term alkaline (pH > 7) is entirely different from the term alkalinity (capacity to resist a change in pH) Alkalinity

Less than 150 ppm – no problem expected; 100 ppm is high for plug production 150 to 300 ppm – increasing concern if the water pH is greater than 7.5. Expect the pH of the growing substrate to increase throughout production of the crop; use acidifying fertilizers regularly, use more acid growing substrate. Greater than 300 ppm – significant problems if the water pH is greater than 7.5. The substrate pH will rise rapidly throughout the production of the crop and cause many nutrient problems. Acid injection into the water may be the only remedy if this water source must be used for irrigation.

Nitrate Nitrogen Less than 5 ppm – no problem expected Greater than 5 ppm – no cultural problems for plant production, however, a nitrate level greater than 5 is a good indication that your water source is polluted. There can be greater variability in this laboratory measurement compared to other measurements.

Phosphorus 0 to 3 ppm – no problem expected Greater than 5 ppm - could interfere with the uptake of other nutrients; addition of P in the fertilization program may not be necessary; could be signal of potential water source contamination by applied fertilizer, detergents, etc.

Potassium 0 to 10 ppm – no problem expected Greater than 10 ppm - no cultural problems for plant production expected. Potassium levels this high in Kentucky water samples are rare and could be potential sign that the potential water source is contaminated with fertilizer.

Calcium Less than 60 ppm – expect calcium deficiencies in plant production unless calcium is added in the fertilizer program. Greater than 60 ppm – no cultural problems for plant production expected. Hydroponic nutrient solutions for plant production use rates of 80 to 130 ppm Ca. Irrigation water with high calcium may need no additional Ca additions through fertilization. Higher amounts of Ca will compete with P and Mg and reduce their availability to plants.

Magnesium Less than 25 ppm – expect Mg deficiencies in plant production unless magnesium is added in the fertilization program. 25 to 50 ppm – should be adequate for production of most plants; hydroponic nutrient solutions use rates of 30 to 50 ppm Mg Greater than 50 ppm – no cultural problems for plant production. Mg levels this high in Kentucky water samples are rare and could be a sign that the potential water source is contaminated with fertilizer.

Zinc 0 to 0.3 ppm – no problem expected Greater than 0.3 ppm - could cause toxicity in sensitive plants, especially at low substrate pH; high Zn in Kentucky water sources is rare and could be a sign that the potential water source is contaminated from old galvanized pipe.

Copper 0 to 0.2 ppm – no problem expected Greater than 0.2 ppm - could cause toxicity in sensitive plants, especially at low substrate pH; high Cu levels in Kentucky water sources are rare

Iron 0 to 1 ppm – no problem expected Greater than 1 ppm – could cause foliar spotting in sensitive plants and clog some micro-irrigation emitters Greater than 5 ppm – can cause toxicity symptoms in some plants, particularly at a substrate pH below 5.5

Manganese 0 to 1 ppm – no problem expected 1 to 2 ppm – usually not toxic to plants but usually not found this high in Kentucky water sources

Boron Less than 1.0 ppm – no problem expected. However, poinsettia is particularly sensitive to boron toxicity from B levels as low as 0.5 ppm. 1.0 to 2.0 ppm – toxicity may be a problem on some plants Greater than 2.0 ppm – expect toxicity symptoms at low substrate pH

Sodium Less than 50 ppm – no problem expected Greater than 50 ppm – expect salt concentration in the growing substrate to increase over time

Recommendations More information = better targeted interpretation and recommendations

High Alkalinity Water Low Alkalinity Water Target pH pH Drift Source: Bailey, 1996

pH = 9 Alkalinity = 50 pH = 7 Alkalinity = 300 Effect of Water Alkalinity on Substrate pH

pH = 9 Alkalinity = 50 Little or no effect on substrate pH pH = 7 Alkalinity = 300 Substantial increase in substrate pH Effect of Water Alkalinity on Substrate pH

Water Quality Treatment Options Total Alkalinity (ppm) reverse osmosis acid injection acid reaction fertilizer no treatment > <

WellMunicipal Creek pH Conductivity Calcium Magnesium Sodium

Water Test Report for Teaching Greenhouse Tap Water Laboratory Results pH 8.2Phosphorus 0.5ppmZinc 0.1ppm Conductivity 0.34mmho/cmPotassium 2.5ppmCopper 0.0ppm Alkalinity 102ppmCalcium 49.4ppmIron 0.0ppm Nitrate-N 1ppmMagnesium 6.6ppmManganese 0.0ppm Boron 0.0ppm Sodium 13.4ppm

Questions?

Soilless Media Testing

Sample Submission Form

Sampling and Handling Variables – Crop species – Planting time – Container size – Environment Limited by block management Timing relative to activities & events Several locations in representative block 6-8 subsamples – Thoroughly mix Submit a 2-pint sample; two sample bags

Submit a Large Sample +

Report of Results

Soilless Media Test Interpretation

Nutrient Concentration Ranges LowAcceptableOptimalHigh Very High pH < >7.0 Soluble Salts – dS/m; mS/cm < >4.5 Nitrate Nitrogen (NO 3 N) – ppm < >300 Phosphorus (P) – ppm < >18 Potassium (K) – ppm < >350 Calcium (Ca) – ppm < > 220 Magnesium (Mg) – ppm < >150

Nutrient Concentration Ranges LowAcceptableOptimalHigh Very High Sodium (Na) – ppm <70 > 70 Iron (Fe) – ppm < > 30 Manganese (Mn) - ppm < > 30 Zinc (Zn) - ppm < > 30 Boron (B) – ppm < – – 2.0> 2.0 Copper (Cu) – ppm < – – 1.5> 1.5

Substrate / Medium ‘Starter Charge’ of fertilizer Lime (Ca and Mg Carbonates) Irrigation Water Fertilizer Factors Influencing Media EC

Ammonium vs Nitrates Ammonium and urea behave the same way in soil reactions and plant utilization Ammonium application reduces pH Nitrate application increases pH NH 4 < 40% of total N Ammonium toxicity

Adjusting Substrate pH NH 4 + H + Acidic reaction NO 3 - OH - Basic reaction NH 4 NO 3 + 2H + + H 2 O Nitrification (acidic reaction) Root

Ammonium Toxicity Can occur when ammonium provides more than 50% of total N Occurs at higher levels of fertility… luxury consumption More prevalent in herbaceous plants than woody plants Yellowing, necrosis, rolling of leaf margins… differs with crop Related to the capacity of the plant to store NH 4

Osmocote 70*F Osmosis (swelling and cracking) PRO or PLUS formulations “Old Staple” Nutricote 77*F Polyolefin membrane (single thickness) Florikote or Plus formulas Japanese product

Recommendations More information = better targeted interpretation and recommendations

Report of Results

Soilless Media Test

Plant Substrate Limestone Irrigation water alkalinity Fertilizer reaction Factors Influencing Substrate pH

Raise pH Adjusting Substrate pH Change water source Use nitrate (NO 3 - ) fertilizer Apply flowable lime drench Top dress with dolomitic lime Apply potassium bicarbonate drench Change water source Use ammonium (NH 4 + ) fertilizer Acidify water Iron sulfate drench Lower pH

Formulation Acidity Potential of Common Fertilizers Ca Ca-1 Mg Ca Ca A 1556 A 1040 A 680 A 429 A 389 A 260 A 40 B 141 B 420 B 400 Fertilizer reaction

Water Test Report for Teaching Greenhouse Tap Water Laboratory Results pH 8.2Phosphorus 0.5ppmZinc 0.1ppm Conductivity 0.34mmho/cmPotassium 2.5ppmCopper 0.0ppm Alkalinity 102ppmCalcium 49.4ppmIron 0.0ppm Nitrate-N 1ppmMagnesium 6.6ppmManganese 0.0ppm Boron 0.0ppm Sodium 13.4ppm

Formulation Acidity Potential of Common Fertilizers Ca Ca-1 Mg Ca Ca A 1556 A 1040 A 680 A 429 A 389 A 260 A 40 B 141 B 420 B 400 Fertilizer reaction

High Alkalinity Water High Nitrate (NO3) Fertilizers Low Alkalinity Water High Ammonium (NH4) Fertilizers Target pH High alkalinity water Basic reaction fertilizer Dolomitic lime top dress Flowable lime drench Potassium bicarbonate drench Adjusting Substrate pH Source: Bailey, 1996

Acid reaction fertilizer Low alkalinity water Acid injection Adjusting Substrate pH Source: Bailey, 1996 High Alkalinity Water High Nitrate (NO3) Fertilizers Low Alkalinity Water High Ammonium (NH4) Fertilizers Target pH

Pour-through Monitoring Non-destructive sampling – Developed by Dr. Robert Wright at VPI Fast and fairly accurate pH and EC status – EC in the 0.5 to 1.5 range during active growth Monitoring and recording over time!

3-minute video UKREC YouTube

Testing EC Different Procedure = Different Results The same medium would show: 1:2SMEPour Through mS/cm

pH and EC Meters Hanna Instruments HI mS/cm HI Portable pH/EC/TDS/Temperature

Nutrient Analysis Foliar analysis – Foliar analysis provides measure of actual nutrient concentration of plant tissue – Problem: Often only very general guidelines are available for “optimal” nutrients concentrations – Concentrations can vary by: age of plant, leaf position, time of year

Nutrient Analysis Commercial Laboratory, such as: Waters Agricultural Laboratories, Inc. Owensboro, KY

Questions?