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Click on the arrows on the variables in the header row to reorder the farm practices based on that variable.

Management areaOn farm
NPSedMOCostBenefitFactors to consider
Whole farm planning Whole farm business and systems analysis - - - - $ $$$ Involves assessment of farm resources, stocking policies and farm business risks. A good starting point that will help clarify the most useful practices to consider in this menu.

Whole farm analysis will identify water quality risks. Likely water quality benefits depend on farm contour, management challenges and practices used to manage risks on farm.
Whole farm planning Whole farm soil test and fertiliser policies optimised as result - - $ $$$ Test all soil nutrients including total nitrogen. Benefits will occur if variability in the range. This might help redefine management units for further fertiliser applications.
Whole farm planning Stock policy - - - - $ $$$ Involves assessment of optimising comparative stock rate, replacement rates, and milk production.

Depend on farm system
Nutrient management Do a whole farm nutrient budget - - - - $ $$ Farm consultant/advisor should use OVERSEER®1 (most recent version) to create a nutrient budget for the whole farm, with recommendations to be included in a nutrient management plan.

Likely water quality benefits will depend on the range of practices used to manage nutrients as a result of nutrient budget recommendations.
Nutrient management Apply N fertiliser in accordance with feed budget, climatic conditions and soil temperatures greater than 7° - - - $ $$$ Refer to the Fertiliser Association’s Code of Practice for Nutrient Management
Nutrient management Keep Olsen P at agronomic optimum using soil testing - - - $ $$$ Avoiding unnecessary application of P will reduce costs. To minimise run off, apply P fertiliser when soil moisture is good and no large rainfall events are forecasted. Consider use of lower solubility P fertiliser if soil conditions allow.
Nutrient management Diet substitution to reduce overall N input (use low protein supplement e.g. maize instead of high protein/high N pasture) - - - $$ $ Requires good quality maize silage and careful feed monitoring and budgeting. Addition of a feed pad will reduce feed wastage, but increases costs. Can improve overall nutrient budget compared to N boosted pasture in spring because low protein supplement is more N use efficient. The benefit of substitution will be lost if the farmer continues to offer the same quantity of high protein feed as well as the new low protein feed to their herd.
Riparian management Fence stock out of waterways $ $$ Lower stock losses in waterways are a key benefit. Fencing can sometimes be used to improve subdivision and pasture utilisation.
Riparian management Put in culverts or bridges at regular stock crossings $ - $$$ $$ Cost will depend on whether culvert or bridge is required. Bridges also require resource consent. Improved crossings reduce lameness and reduce stock and vehicle travel time.
Riparian management Fence stock out of wetlands and maintain water levels (i.e. avoid drainage) on flat land
on steeper land
$ - $$ $$ N removal effectiveness depends on wetland type, paddock slope, how long water stays in the wetland (the longer the better), and stock management (no pugging or erosion). Fenced wetlands reduce stock losses and improve habitat for wildlife and fish. Appropriate planting and weed/pest management can further increase benefits.
Riparian management Constructed wetlands $$$ $ High cost option to improve water quality of run off before it enters a stream or river e.g. from tile drainage. Not effective if little or no surface run off. Factors to consider include optimal wetland size for catchment area, ability to harvest vegetation occasionally and weed and pest control. Can provide habitat for wildlife and fish.
Riparian management Riparian planting $$$ $ Effectiveness improves with a grass margin to help filter run off, especially on steeper slopes. Effectiveness depends on species planted. Ongoing weed and pest management is an added cost but reduces with time. Can improve bank stability, provide habitat for wildlife and instream shade for fish and insects.
Riparian management Sediment trap (an engineered structure to slow water flows, reduce energy, filter sediment and allow grass growth e.g. decanting dam, detainment bunds) $$$ $ Most useful where steady flow of run off to waterways during wet periods and sediment/P is an issue. Detainment bunds designed to allow ponding for no more than three days to maintain pasture. Require water storage of around 120m3/ha of contributing catchment. Can be costly where not using existing structures. Requires sound engineering design and ongoing maintenance.
Effluent management2 Increase land application area $ $$ Can be beneficial where effluent K loads are above pasture requirements with potential to affect animal health. Maximum nutrient gains can be achieved by using a whole farm nutrient budget. Will depend whether further suitable land (topography and soil type) is available. Is likely to require changes to irrigation system design. Can allow better fit with grazing rotation.
Effluent management2 Move to land application system from two pond discharge to water system $$ - $$$ $$$ Very effective for reducing nutrients to waterways but increases farm labour requirements. Can be a more cost effective alternative to upgrading old pond systems and allows for reuse of nutrients in the farm system, potentially reducing fertiliser requirements over time. Maximum nutrient gains can be achieved by using a whole farm nutrient budget. Less feasible in steep areas or areas with poor soils.
For more information, check the soil map at for effluent areas.
Effluent management2 Minimise effluent volumes at source (by reducing wash water volumes and rainwater in the system) $ $$ Reduces pumping cost and need for storage. Improves water efficiency on farm.
Effluent management2 Grow maize on the effluent block - - $ $$ Effective for N and K removal and allows lower cost maize growth on farm with less fertiliser. Requires good maize management to minimise leaching, including direct drilling, avoiding mid-winter cultivation and timing any N applications to match peak plant uptake using split applications or slow release N. Use of additional N fertiliser will reduce benefit of N loss, so should be done in accordance with soil tests. Affects stock rotations in summer if effluent block not available for grazing.
Effluent management2 Export effluent solids to run off or cropping areas $ $$ Most useful in Dairy System 5 and assumes solid separation already occurs. See Water quality benefits only realised if fertiliser use remains unchanged. Suits low rate effluent application systems (<6mm application depth). Higher cost and labour for solids separation and transport but option to lower N and K for high input system in sensitive catchment. Receiving farm will ideally have a nutrient budget to manage effect of imported nutrients.
Effluent management2 Monitor soil moisture deficit for effluent irrigation and use information to improve timing of effluent applications - $$ $ Ensures shed and feed pad effluent is applied without direct discharge to water or draining to groundwater. May mean increasing effluent storage capacity during wet periods. Use pond calculator to estimate pond storage required.
Effluent management2 Optimise the volume of shed, yard and cleaning water $ $ Maximises storage capacity available, allow effluent to be applied to land in optimum conditions. Flood wash with water from the effluent pond (refer to conditions of use from your milk processor).
Effluent management2 Optimise the volume of feed pad cleaning water $ $ Recycle green water for feed pad cleaning.
Effluent management2 Prior to spreading, locate sand trap heaps on sealed pads and away from watercourses and drains - $ - Ensure drainage is back to the pond so contaminated rainwater can be captured and contained.
Effluent management2 Low rate effluent irrigation $$ - $$$ $$ Requires some solid separation. Allows more ’safe‘ irrigation days per year and lowers overall effluent storage need. Allows application to steeper land but can be challenging to keep application rates consistent. Cost dependent on system choice.
Effluent management2 Increase storage volume and using deferred irrigation $$$ $$ Can be high cost as most existing pond systems are not able to be used for storage. Can be challenges with mechanical desludging. Lowers risk of effluent run off during wet and/or busy periods.
Off pasture options Use controlled grazing regimes (within paddocks, on-off grazing or opening up more feed ahead of storms) to reduce risk of N leaching, run off, soil loss and compaction $ - $$$ $$$ On-off grazing requires a stand-off pad and effluent storage, but feed wastage and soil compaction are reduced. Low cost if existing stand-off facilities on farm. Benefit is greatest on farms with high risk soils.
Off pasture options Use of off pasture facility (e.g. shelters or loafing pads) suitable for removing stock from pasture during prolonged wet or dry periods (using bought in feed) $$ - $$$ $$ Requires feeding and effluent capture facilities with adequate storage and land application area. Also requires a revised nutrient budget to take into account the value of supplementary feed. Requires different set of management skills from pasture-based farming systems. Benefits depend on soil type and climate.
Off pasture options Cut and carry pasture management with feeding facilities $$$ $ Requires a feed pad and appropriate effluent capture facilities. Management skills required are very different to those developed in traditional NZ farm systems.
Off pasture options Graze cows off farm in winter $$ $$ Water quality benefit for catchment but exports the issue elsewhere. Farmer loses some control of stock health and condition when stock off farm.
Protecting soil health with good grazing management Avoid grazing heavy stock on steeper or more vulnerable soils especially when wet $ $ - $$$ Keeping stock off saturated soils may be as easy as shifting stock to a different soil type on farm through to stand-off facilities. Cost-benefit depends on options chosen to take stock off pasture. Highest benefit on high risk soils.
Managing critical source areas - hotspots
(high sediment, phosphorus or faecal loads coming from small areas of high run off)
Reduce run off from tracks and races (using cut-offs and shaping) $ $$ Cost and effectiveness depends on contour of farm (higher risk of soil loss on steeper land but will also require more work). Requires regular maintenance but can reduce lameness, water damage and long term maintenance costs.
Managing critical source areas - hotspots
(high sediment, phosphorus or faecal loads coming from small areas of high run off)
Move water troughs and gateways away from water flow paths $ $ These areas of concentrated stock use have high nutrient loads and reduced vegetative cover so are higher risk for run off. Cost and effectiveness depends on contour of farm (higher risk of soil loss on steeper land but greater benefit).
Managing critical source areas - hotspots
(high sediment, phosphorus or faecal loads coming from small areas of high run off)
Fence and plant springs and permanent wet and boggy areas $$ $$ Benefits will be proportional to the number of sites and total area retired. Effects for nitrogen will also be proportional to the groundwater catchment and therefore the benefits may be more than just the wetland area.
Managing critical source areas - hotspots
(high sediment, phosphorus or faecal loads coming from small areas of high run off)
Fence and plant out unproductive steeper slopes - $$$ $$ Planted steeper slopes will slow water movement from this area and reduce the potential for erosion Will reduce weed control costs and lower fertiliser expenditure.
Managing critical source areas - hotspots
(high sediment, phosphorus or faecal loads coming from small areas of high run off)
Replace summer and winter sacrifice paddocks with sealed loafing pads $$ $$ Allows pasture to recover quicker after prolonged wet or dry periods. Collected effluent will be stored in effluent pond for late spring application. Requires effluent capture and storage for land application.
Managing critical source areas - hotspots
(high sediment, phosphorus or faecal loads coming from small areas of high run off)
Use low N crops - - $ $ Fodder beet and fodder radish have low N content and lower N urinary deposition. The benefit depends on how you use the crop in your farming system.
Cropping management Reduce soil cultivation by adopting strip tillage or direct drilling - $ $$ Effective for reducing run off and soil loss, and improving soil quality and infiltration. Soils that have been grazed over the winter may be compacted or pugged, requiring more cultivation or resulting in rough paddocks. Requires modified planter machinery to deliver good seed placement for even plant establishment. Additional expenditure might be required for insect pest control. FAR trials show cost-benefit of $200/ha if crop establishes/yields similarly.
Cropping management Maintain buffer strips on sloping cropping paddocks - $ $ Reduces risk of soil loss from heavy rain events. Benefit will be proportional to area cultivated.
Cropping management Establish autumn pastures early - $ $$ Suggested planting date for perennial pasture is before 31 March, regardless of soil moisture. Consider earlier maturing varieties as previous crop’s harvest date is a factor. Nitrate benefit will be proportional to the area cultivated.
Cropping management Use active winter crops - - - $ $ Winter active crops (oats, rape, Italian rye) may reduce N leached.
Cropping management Cultivate along contours (rather than up and down the slope) where slopes greater than 3° - $ $$ Slows down run off and reduces erosion. Row orientation should follow contour.
Cropping management Time N application to meet crop demand using split applications or slow release N - - - $ $$ By targeting crop demand better uptake of nutrients by crops and lower losses occur. Split applications are more costly and management intensive.
Cropping management Actively manage grazing of winter forage crop areas to reduce risk of N leaching, run off, soil loss and compaction $$ $$ Graze from top to bottom of paddock contour. Avoid leaving stock on during wet periods, for long periods, or concentrated on small sections of the crop.
Cropping management Graze crops and pasture towards waterways, rather than away from them $ $ Applies to grazed paddocks in wet weather with overland flow that converges to form small channels of running water. Will capture run off from grazed areas. Benefit will be proportional to area grazed.
Cropping management Use placement tools e.g. GPS guidance, crop sensing, where possible - - $$$ $$$ Delivers more precise nutrient inputs for expected crop yield. Likely to become more widely used as tractors are upgraded over time.
Cropping management Include grass buffer strips (2m or more) for cultivated land next to waterways - $$ $ Effective for filtering run off and reducing the risk of fertiliser loss during spreading. More benefit on greater slope but wider buffer required. Grazing of buffers only appropriate for ephemeral waterways during summer dry. May require weed management but can provide habitat for beneficial predatory insects, reducing need for pest control.
Irrigate to avoid increased drainage and run off Measure and record soil moisture and rainfall to develop a water budget - - - - $ $ There is value in collecting farm data to inform management decisions. Note that one will need local evapotranspiration data to complete the water budget.
Irrigate to avoid increased drainage and run off Use water budget to schedule irrigation - - - - $$ $$ Water scheduling increases water efficiency. Benefits will depend on current practice, soil type and farm system. Seek professional advice on water scheduling and irrigation type (e.g. low pressure v flood v high pressure).

Depend on irrigation type and farm system
Irrigate to avoid increased drainage and run off Do not exceed soil water infiltration rate - - - - $ $$ Benefits will be dependent on current practice, soil type and farm system. Seek professional advice to avoid drainage.

Depend on irrigation type and farm system
Irrigate to avoid increased drainage and run off Maintain irrigation equipment - - - - $$ $$ Check pipes are not leaking and nozzles are working well.

Depend on irrigation type
Emerging technologies currently in development Precision fertiliser applications - - $ $ GPS application of fertiliser is currently used to improve accuracy of application and can result in improved N conversion efficiency and reduced fertiliser use. Maximum benefits achieved where waterways or critical source areas (high sediment, P or faecal loads) are avoided.
Emerging technologies currently in development Use of gibberellic acid to boost pasture growth - - - $ $ Only provides water quality benefit if used as an N substitute to reduce overall N inputs. Plant hormones should be used with care.
Emerging technologies currently in development Consider deeper rooted species in pasture composition - $ $ Mixed swards (e.g. chicory, lucerne) recover more soil N between January to May than does barley or pasture.
Farm training Embed environmental management into farm practices through training and incentivising staff $ $ The level will depend on the staff members experience in environmental practice and ability to influence on farm practice change.
Farm training Ensure staff responsible for effluent management are adequately trained $ $ AgITO courses available.


  1. The OVERSEER® nutrient budgeting programme assumes many ‘low’ rated practices, such as following effluent management guidelines, are already in place. If these practices haven’t yet been implemented, OVERSEER® is likely to underestimate nutrient losses. Making these changes over time may result in little change to your OVERSEER® nutrient budget even though you are achieving positive change on the ground.
  2. Any changes to effluent storage systems must be undertaken in accordance with Industry Practice Note 21. Land applicaton of effluent must be undertaken in accordance with best practice. See for more information on effluent management best practice.