What You Can Do On The Farm

Our Land and Water recommends more than 40 types of mitigations, which go beyond industry good practice to additionally reduce agricultural contaminants entering New Zealand’s waterways. However our research tells us it will take more than mitigation to achieve our country’s water quality goals: land use change will also be required in many areas.

• Our National Register of Actions research team is creating a national, online map that will link a recommended suite of actions to improve water quality, with outcomes at the nearest water quality indicator site. Meanwhile, the resources below may help.
• Find a list of mitigation strategies in Assessment of Strategies to Mitigate the Impact or Loss of Contaminants from Agricultural Land to Fresh Waters (table 4, page 13–22), a report for the Ministry for the Environment. These mitigations allow you to reduce nitrogen and phosphorus losses from your farm by 20% to 50%, without costing more than 2%–10% of farm earnings before interest and tax.
• Many on-farm options to reduce agricultural GHG emissions in New Zealand (identified in this July 2017 report to the Biological Emissions Reference Group) also have co-benefits for water quality.
• Mitigations should be mixed and matched, applied based on cost and suitability to your property, says Our Land and Water chief scientist Rich McDowell. Advances in farm mapping (eg MitAgator) to develop farm environment plans (eg via your Regional Council-approved providers) can identify your critical source areas and allow mitigation practices to be targeted precisely, improving their cost-effectiveness.
• Applying farm dairy effluent (FDE) to shallow free-draining soil can significantly increase phosphorus leached to waterways, where it stimulates algal growth. Our research suggests that FDE should not be applied to freely draining shallow stony soil (or similar soils) under irrigation. Effluent technology is newly becoming available that separates FDE into treated water and solids within effluent ponds.
• Our research has shown that 77% of stream contaminants come from small streams that aren’t required to be fenced or planted. We encourage you to extend livestock exclusion strategies such as riparian planting beyond the minimum required, to smaller streams on your farm.
• Using variable rate irrigation to adjust the volume of irrigation water according to soil type and soil conditions can cut the amount of nitrogen and phosphate being lost by 70%-80% compared to standard irrigation practice, found our Sources and Flows research. For farmers interested in seeing if precision irrigation could help reduce their nutrient losses, the first step would be to map the soil on their property to see if it is variable or consistent, said former IrrigationNZ CEO Andrew Curtis. For properties with variable soil types, using variable rate irrigation is worth investigating further.
• The next step is to use soil moisture sensors to minimise drainage. Sensors can also control irrigation systems automatically. If there’s no drainage, there’s no leaching. All the moisture and nutrients being applied through irrigation stay within the root zone to be utilised by the plants.
• In some areas, some farm systems may not meet water quality goals, even with the right mitigations in the right place. Before investing heavily in mitigations, it’s worth reconsidering what your land is most suitable to produce. Our Land Use Suitability research is developing tools that will help.
• Iterative land-use changes, beginning with your critical source areas, can better match production to your land. “Practising adaptive management – where you try a plan, see how it works, then modify it – that incremental improvement is the way to go forward,” says Scott Larned, of Our Land and Water’s Land Use Suitability programme.
• Forestry, native regeneration, fruit or arable crops may be more profitable than livestock agriculture, particularly when future policy requires greenhouse gases and agricultural contaminants to be fully accounted for. Currently untried or experimental land uses could create even more value. Our Land and Water research into next generation farming systems is exploring such options, and ways to overcome risks and barriers.
• Find Our Land and Water-backed land-use tools in the Toolbox.