How do you measure humic acid concentration?
It is based on the oxidation of humic acids and the identification of their oxidation products. Molecular bromine is used as an oxidizer (its amount in solution is 0.05-0.25%) and detection is carried out by capillary gas chromatography. This method is accurate and reliable.
How does humic acid dissolve in water?
Humic acid is insoluble in water at any PH. You can dissolve the acid in Basic solution such as NaOH and bring down the pH to required level by slowly adding acid solution.
How much humic acid is in drinking water?
Mix 2 ounces of liquid humic acid per gallon of water. Use a pump sprayer with the nozzle held 2–6 inches above the grass to spray the humic acid mix evenly over the grass.
How do you isolate humic acid?
Reprecipitate the humic acid by adding 6 M HCl with constant stirring to pH = 1 and allow the suspension to stand again for 12 to 16 h. Centrifuge and discard the supernatant. Suspend the humic acid precipitate in 0.1 M HCl/0.3 M HF solution in a plastic container and shake overnight at room temperature.
How do you test for fulvic acid?
Currently, the HPTA method is the only test recognized as being capable of accurately measuring fulvic acid. It measures the “hydrophobic” fraction of fulvic acid. There may be other fractions to fulvic acid (hydrophilic), but at this point there is not an accepted test to measure this.
How do you mix water with humic acid?
For soil or hydroponic system at a 12% solution of Humic: 1. Mix 1.25 lbs of Powder into 1 US Gallon of Water. 2. Mix small amounts at a time and stir and blend until well dissolved.
Does humic acid affect pH?
The addition of humic acid will exchange H + cations to cause lower soil pH. The higher the content of clay and organic matter, the smaller the pH change, as in the case on soil 2.
How do you make humic acid?
You can either extract humic acid from a humus rich soil sample, from peat moss or from humic compost. If you regularly add humic compost to your garden then sourcing humic acid from both humus laden soil or the organic compost would be easy, though quite tedious.
How is the weight of humic acid determined?
The weight of ash-free humic acid was derived from 10 g air-dry soil, therefore should be multiplied by 10 to convert to percent air-dry soil and further converted to percentage oven-dry soil. The fulvic and humic acid content may be expressed as a percentage of total soil organic matter, which is quantified as soil organic carbon (SOC).
How are fulvic acids and humic acids related?
Aiken et al. (1985) have defined fulvic acids as ‘the fraction of humic substances that is soluble under all pH conditions’, and humic acids as ‘the fraction of humic substances that is not soluble in water under acid conditions, but becomes soluble at greater pH’.
How to determine the optical density of fulvic acid?
Decant the solution of fulvic acid into a 250-ml volumetric flask. Wash the sediment of humic acid with 30 ml 0.5 M HCl, centrifuge, add supernatant to the volumetric flask, and make up to the mark with water and mix. Read the optical density at 465 nm, diluting if necessary to bring on scale.
How to calculate fulvic acid from air dry soil?
Calculation. Ash-free fulvic acid y mg 100 ml-1 is read from the chart. This solution resulted from 10 g air-dry soil in 250 ml solution. Therefore 250 ml solution contains y x 250/100 mg fulvic acid from 10 g air-dry soil, which converts to 25y mg fulvic acid 100 g-1, or 0.025y% air-dry soil.