Micro-nutrient dosing

Micro-nutrient dosing

• Overview
• Links and references

Other name/s

Inorganic micro-nutrient fertiliser dosing

Description

Inorganic micro-nutrient dosing boosts diatom growth with the result that inorganic nitrogen and phosphorus (N and P) concentrations in the waterbody are reduced as diatoms take up these macronutrients when they grow. As the diatoms preferentially take up nutrients, undesirable cyanobacteria (blue-green algae) are reduced[1][2].

Micro-nutrient dosing uses a range of micro-nutrients specifically selected to promote plant and diatom growth. Using nano-technology, these micro-nutrients are adsorbed to nano-scale gels of silica. This makes the nutrients chemically unavailable unless the silica gel is used by the diatoms. As diatoms are the only microalgae or cyanobacteria to have a requirement for silica, only the diatoms receive a boost from the micro-nutrients.

When the diatoms get the micro-nutrients they are able to grow more (on a biomass basis) than if they were micro-nutrient deficient. Therefore they take up more inorganic nitrogen and phosphorus from the water to support their growth. As the diatoms are the basis of many food webs, they provide a bioavailable/readily mobile way to move the nutrients nitrogen and phosphorus into the food chain. Further research is required to determine the fate of the nutrients.

This treatment technology was originally designed to control blue-green algae blooms, but with a reduced concentration of N and P in the water, growth of other algae and macrophytes are reduced. In some cases, where treated wastewater with diatoms has been used to irrigate pasture land, operators have observed improved soil structure and nutrient content.

Services and benefits:

• Blue green algae (Cyanobacteria) control
• Water treatment
• Beneficial re-use of treated water

References

1. ^ Tannock, S (2016), Presentation to the Treatment Systems in Coastal Catchment Forum. [online], Department of Environment and Heritage Protection. Available at: https://wetlandinfo.des.qld.gov.au/wetlands/management/treatment-systems/for-agriculture/treatment-sys-nav-page/treatment-forum/index.html.
2. ^ Tannock, S (2018), Presentation to the Treatment Systems for water quality improvement - Regional Forum. [online] Available at: https://wetlandinfo.des.qld.gov.au/resources/static/pdf/management/regional-forum/6-tannock.pdf.

Last updated: 10 June 2022