Iron is essential nutrient to plants, however in large amount it causes toxicity and deterioration of soil quality. Iron binds phosphorus and molybdenum, essential nutrients, reducing their availability to the plants. In addition the imbalance of a few nutrients has a domino effect on toxicity levels and availability of other nutrients. When water is sprayed on plant leaves, iron may precipitate to form slime or light brown spots which interfere with availability of sunlight and general biological processes and adversely affect the product’s appearance and marketability. More soil conditioners, fertilisers and chemicals to treat plant diseases are needed to counterbalance the damages caused by excessive iron in irrigation water. As such, there are recommended limits to the concentration of iron in irrigation waters.
- No more clogging
- Reduce downtime
- Significantly improved system performance reducing initial system capital investment
- No leaching of chemicals
- Substantial whole of life cost savings
Broadcast sprinkler systems use water inefficiently, and in some jurisdictions the practice has been banned or is in the process of being phased out. This will require migration to drip feed systems, which are very susceptible to clogging problems when water sources contain Iron and manganese contamination as well as particulate matter, including debris or algae. Clogging of drip feed systems results in very high maintenance overheads and loss of production. The problem can be reduced by improving the quality of irrigation water.
Apart from aesthetic problems, irrigating with large amount of iron in the water is not a long term sustainable solution. The short term (20 years) trigger value for iron toxicity and soil deterioration is a maximum of 10 mg/l in the water used for irrigation.
Typical sources of iron fouling are
- Anoxic aquifers containing soluble divalent iron and/or manganese
- Hydroxide flocs of oxidized iron and/or manganese from raw water
- Natural organic matter (NOM) containing iron complexes
- Hydroxide flocs from coagulation process
- Corrosion products from piping materials used for the feed water
- Silicates containing iron