Nutrient Analysis (NPK)
The chemical composition of a nutrient solution includes differnet chemical elements. Nutrient analysis is necessary for better management of fertilization and to know the residues of fertilizers in relation to the crop. An analysis can highlight shortages and help the understanding of the causes of an abnormal growth. The three elements that are most needed by plants are nitrogen (N), phosphorous (P) and potassium (K).
Nitrogen (N) is indispensable for the plant’s life and is a key factor in fertilization. Nitrogen allows the development of the vegetative activity of the plant, in particular, causes lengthening of trunks and sprouts and increases the production of foliage and fruits. An excess of nitrogen weakens the plants’ structure creating an unbalanced relationship between the leaves and the stalks. In addition, the plant becomes less resistant to diseases.
Phosphorous (P) is an important element in the composition of DNA and RNA and the regulators of the energetic exchange (ATP & ADP) in plants, as well as the reserve substances in seeds and bulbs. It contributes to the formation of buds, roots, blooming, and lignification. A lack of phosphorous results in: stifling of plant, slow growth, a reduction of production, smaller fruits and a lower expansion of the roots.
Potassium (K) is not a constituent of important compounds but it plays a remarkable role in many physiological activities like the control of cellular turgor and the accumulation of carbohydrates. It increases the size of fruits, their flavor, as well as yielding a positive effect on the color and fragrance of flowers. Potassium also makes plants more resistant to disease.
Hanna offers a variety of methods to measure and monitor nutrients. The method used will be determined by specific analysis desired. For example Nitrogen can be measured as ammonia, nitrate, or with a digestion procedure total nitrogen can be measured. The same would apply to phosphate/phosphorous. Most tests will measure phosphorous as orthophosphate. To measure all phosphorous present, including organically bound, would require digestion.
Below are the most common products used hydroponic nutrients measurement.
Benchtop Photometers & Spectrophotometers
Available are benchtop photometers and spectrophotometers that have build in methods for nutrient analysis. The benchtop photometers feature a digital pH electrode input turning the meter into a professional pH meter.
Single parameter photometers are available to measure ammonia, nitrate, and potassium. Multiparameter portables are available that measure calcium and manganese hardness. The portable photometers have a CAL Check feature that allows for performance verification and, if needed, recalibration using the CAL Check standards. The portable meters are available as a meter only or as a kit. The kit version includes a rugged carrying case and CAL Check standards.
Checker Handheld Colorimeters
Checker HC, like chemical test kits, are reagent based with a color change based on concentration. The handheld colorimeters, like portable and benchtop instrumentation, use the Beer-Lambert principle to determine the color change.
Chemical Test Kits
Multiparameter Chemical Test Kits (CTK) are available to measure nutrients in solutions. These kits include other key parameters including nitrogen and potassium.
For educational use there is the Hanna Backpack Lab for Soil Quality. The Backpack Lab includes a phosphorus test kit along with a teacher’s guide that discusses the importance of the parameter.
Replacement reagents for the photometers, Checker HC, and chemical test kits. Reagents include multiple forms of phosphorus including reactive (orthophosphate as phosphorus) and Total Phosphorus. Also in this category are reagents for multiple forms of Nitrogen including ammonia, nitrate and total nitrogen.
Solutions for nutrient measurement include the CAL Check standards for verifying and, if needed, the calibration of our portable photometers. Each CAL Check standard is supplied with a Certificate of Analysis stating the accuracy and traceability of the standard.
Accessories include the replacement cuvettes and caps for the photometers and Checker HC. Also included is the COD reactor that is used to digest the samples for total phosphorus and total nitrogen measurements.