‘Adverse environmental impacts’ refer to any harmful effects on the environment – for example, degradation of soil, water or air, changes that reduce flora or fauna habitat or make the local environment socially unacceptable.
Adverse environmental effects associated with nutrient management can occur through one or more of the following mechanisms:
- Leaching - occurs when water carrying dissolved nutrients moves beyond the plant root zone.
Potential consequences include harmful contamination of groundwater or waterways, and poor performance of target crops if necessary nutrients are lost in leaching.
- Runoff - storm water and surface water run-off carrying nutrients away from the target area.
Potential consequences include algal blooms in waterways, water contamination making the water source unsuitable for farm or domestic supply, and reduced nutrients available to the crop or pasture on the target area.
- Airborne - air quality effects associated with dust arising from fertiliser handling and application.
Potential consequences include poor air quality (dust, odour), complaints from neighbours and contamination of water bodies and water supplies.
- Mine - declining soil fertility due to net export of nutrients in product without replacement.
Potential consequences include declining soil fertility, falling production, reduced feed value of pasture or crops and lower profit.
- Load - the accumulation of nutrients and undesired substances, particularly on non-target areas.
Potential consequences include imbalances of nutrients in soil and produce, and toxic levels of nutrient.
- Atmospheric - greenhouse gas emissions that occur when nitrous oxide (N2O) and nitric oxide (NO) are released from urine patches and as nitrogen fertiliser products are converted to nitrate.
Potential consequences are increased emission of greenhouse gases.
This Code provides a procedure for managing or avoiding the potential adverse environmental impacts associated with nutrient use on a range of farming systems.