Description
Nitric acid, with chemical formula HNO3, is a strong acid present in nature in the form of salts called nitrates. This acid is a powerful oxidizer that can attack most metals. In the field of agriculture, nitric acid is widely used in the fertigation sector to regulate the pH of water and improve crops.
One of the main uses of nitric acid is the acidification of the fertilizer stock solution. By reducing the pH to a value below 1, the final solution, mixed with water, will have a pH between 5 and 6, ideal for proper fertigation and solubility of elements in the soil.
However, irrigation water may contain bicarbonates and insoluble salts that can cause clogging in filters and drippers. To avoid this problem, it is advisable to remove bicarbonates until reaching a concentration of only 0.5 meq/L in the stock solution.
To determine the amount of nitric acid to use to neutralize bicarbonates, it is necessary to know the amount of bicarbonates present in the irrigation water. The most practical way to obtain this information is to perform a water analysis, which will provide pH, nutrient, and bicarbonate values in meq/L and ppm (parts per million).
For every cubic meter of irrigation water, it will be necessary to add 83 ml of nitric acid (54% acid) to neutralize 1 meq/L of bicarbonate.
