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Nitrate Measurement in Turf Grass

Nitrate concentration in grasses can be used as an indicator of soil nitrogen (N) availability for their growth. Research at the University of Connecticut suggests verdure sap nitrate-N concentrations at 200-300 ppm as the optimum level.


Introduction

Grasses store nitrogen (N) as nitrate in the bases of stems and shoots. Research conducted by Guillard and Morris (2013) at the University of Connecticut suggests that nitrate accumulate in the shoot bases of perennial turf grasses during the fall (when new leaf blade formation declines), which could be a significant source of N for the turf plant at the onset of new growth in the following spring after winter dormancy. At the optimum critical level of nitrate-N concentration and beyond, the turf response will plateau or flatten out – increasing the fall verdure nitrate-N concentrations with more fertilizer beyond the optimum critical level will not increase the grass quality in the fall or the following spring; the maximum quality response has been reached.

Pocket-sized LAQUA twin Nitrate Ion meter was used to measure nitrate-N concentrations in verdure sap. It eliminates the need to transport samples to a laboratory for expensive analysis performed using either colorimetry or chromatography by trained analyst.


Method

Calibrate the LAQUAtwin Nitrate Ion meter according to manufacturer’s instructions.

Sample Collection And Preparation

  1. Mow the turf to desired height and remove mowed clippings.
  2. Collect verdure samples—aboveground parts of the turf plant remaining after clippings removed. A golf-ball sized, compressed verdure sample is usually sufficient to produce adequate sap for the test.
  3. Squeeze the sap from the verdure sample using a hydraulic or garlic-type press.

Sample Measurement

  1. Place some drops of the extracted sap directly into the sensor.
  2. Record the reading once stabilized—☺ appears.
  3. After each sample, rinse the sensor with water and blot it dry with tissue.
Collect verdure samples—aboveground parts of the turf plant remaining after clippings removed. A golf-ball sized, compressed verdure sample is usually sufficient to produce adequate sap for the test.

Place some drops of the extracted sap directly into the sensor.

Record the reading once stabilized—☺ appears.


Results and Benefits

Research at the University of Connecticut suggests that no fertilizer is required in the fall if the verdure sap nitrate-N concentrations are 200-300 ppm or above during October through November in their climate (critical values were based on turf mowed to a height of 2¼ inches and test was conducted using Horiba’s LAQUA twin Nitrate ion meter). If less than 200, it suggests that some nitrogen be applied to obtain optimum turf responses. When readings are between 100 to 200 ppm, 0.25 to 0.33 lbs N/1000ft2 can be considered. If readings are less than 100 ppm, then 0.33 to 0.50 lbs N/1000ft2 can be considered, provided that N is applied before the onset of winter.

Reference

Guillard, Karl and Morris, Thomas. The Verdure Sap Nitrate Test To Guide Fall N Fertilization of Turf Sod. Sod Nutrient Management Technical Guide TG-0265-R1, June 2013

Matching products

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Horiba LAQUAtwin Nitrate Ion (NO3-) Tester for crops, in carrying case with 5 Pipettes, Crop sample press, 3 cups
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Measuring range: NO3-: 6 to 9900 ppm (mg/L) - (0.1 to 160 mmol/L) | NO3-N: 1.4 to 2200 ppm (mg/L)| 0 to 50.0 ºC | Measurement parameters: Nitrate Ion | Temperature
The LAQUAtwin Nitrate Ion Handheld Tester (NO3-11C) included in the analysis kit is pre-set by the factory to the relevant calibration points 300PPM and 5000PPM for plant sap analysis. Manufacturer Part No. 3200689163  | B-741

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Horiba 4M LAQUAtwin Kit with Sodium, Potassium, Nitrate and Calcium Ion Tester
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With the HORIBA 4M LAQUAtwin Kit you get a high-quality mobile laboratory for your analyses. The high-quality case contains the well-known ion selectives "Made in Japan" LAQUAtwin Pocket Tester for sodium, potassium, nitrate and calcium determination and offers you a price advantage, as you receive the case including accessories free of charge compared to a single purchase.  The lid of the case itself contains a storage box for the colour-sorted calibration solutions included in the scope of delivery, as well as a wash / spray bottle for easy cleaning of the sensors. The case itself can hold up to seven HORIBA LAQUAtwin Pocket Testers, so simply add the additional testers you want to the shopping basket and we will take care of everything else. As usual, the manufacturer provides a two-year warranty and the devices offer the advantage that the sensors can be stored dry and you do not need any storage solutions. Do you have any questions? Please feel free to call us! Manufacturer Part No. 1300083234

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Horiba LAQUAtwin Nitrate Ion (NO3-) Tester with 2 calibration points and temperature measurement (NO3-11)
Product number: 895659
Measuring range: NO3-: 6 to 9900 ppm (mg/L) - (0.1 to 160 mmol/L) | NO3-N: 1.4 to 2200 ppm (mg/L)| 0 to 50.0 ºC | Measurement parameters: Nitrate Ion | Temperature
Manufacturer Part No. 3200689162 LAQUAtwin NO3-11: The world's first pocket-sized nitrate ion analyser Your mobile laboratory - for use on site: Ideal for water quality tests in agriculture, plant breeding and many other applications HORIBA's unique compact meter integrates electrode, display and sample container to enable simple, effective on-site testing by direct measurement with a single drop. Minimum sample volume: 0.3 ml (0.05 ml with sampling sheet B) Up to 2 calibration points Automatic standard detection Adjustable high and low calibration values Multiplication compensation: 0.01 to 9.90 Temperature and mV display Temperature calibration: 5 to 40.0 ºC Auto-hold / auto-stable measurement Automatic switch-off: 30 min. Low battery indicator IP67 rating dust and waterproof Replaceable sensor 400 hours battery life: continuous operation without backlight Material: ABS epoxy Display: customised (monochrome) digital LCD with backlight Operating conditions: 5 to 40 ºC, 85% or less relative humidity Warranty: 2 years - meter, 6 months - sensor Packed in a practical carrying case Supplied with accessories (see specifications for more details)

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Horiba LAQUAtwin Nitrate Ion (NO3-) Tester for soil in carrying case with 5 Pipettes, 3 bottles (100 mL), 2 sampling spoons, tweezers, sampling sheet B, 2 Sampling sheet holders
Product number: 895689
Measuring range: NO3-: 6 to 9900 ppm (mg/L) - (0.1 to 160 mmol/L) | NO3-N: 1.4 to 2200 ppm (mg/L)| 0 to 50.0 ºC | Measurement parameters: Nitrate Ion | Temperature
The LAQUAtwin Nitrate Ion Handheld Tester (NO3-11C) included in the analysis kit is pre-set by the factory to the relevant calibration points 30PPM and 300PPM for soil analysis. Manufacturer Part No. 3200689164  | B-742

€515.00*