Ferruginous water and drip irrigation of asparagus

Iron is dissolved in water in the form of ferrous oxide and is transformed into ferric oxide during pumping, an oxide that is suspended in the water in particles of 0.5 microns and more, the build-up of which will clog drippers.

When ferrous oxide levels get too high

Iron bacteria grow in an anaerobic environment. In contact with oxygen, the oxidation of iron and the death of bacteria cause the appearance of an orange gelatinous mass that may clog drippers. This contamination of iron-rich groundwater is difficult to precisely predict. However, above an iron (ferrous oxide) level of more than 1.5 ppm (1.5 g/l), an iron removal plant should be installed.

Sand filters

Various sand filter methods can be used. The most effective is the injection of air into an oxidation tower and then filtration of the ferric oxide particles either via a sieve or disc filters or, better still, sand filters with automatic backwash. Sand filters are preferable for long-term drip installations. It should be noted that their use significantly raises the pH of the water, something that needs to be taken into account for ferti-irrigation. Successive waterfalls and settling in a basin before pumping and filtration are also a possible solution. Injection of caustic soda (aqueous solution of sodium hydroxide) is also possible. In short, In the presence of iron, the operation of drip irrigation requires increased vigilance and high-performance equipment to ensure the efficiency and sustainability of the installation.