Nutrient Management Plan (NMP)

What

A nutrient management plan (NMP) is a written plan that describes how the major plant nutrients nitrogen, phosphorus, sulphur and potassium (and any others of importance to specialist crops) will be managed.

The nutrient management plan aims to optimise production and maximise profit value from nutrient inputs while avoiding or minimising adverse effects on the environment.

A good NMP:

  • Ensures that nutrient management meets all legal and industry requirements.

  • Includes a nutrient budget (such as Overseer) which compares nutrient inputs from all sources with all nutrient outputs.

  • Achieves desired changes in nutrient levels and production (e.g., increasing soil fertility from a poor base to support the higher stock carrying capacity; altering soil nutrient status to suit future crops),

  • Minimises the cost of supplying nutrients and avoids wasted spending on unnecessary or unused nutrients.

  • Minimises the risk of damage to the environment.

  • Considers the land manager’s personal objectives.

A template from the Fertiliser Association can be accessed from:

http://www.fertiliser.org.nz/Site/code-of-practice/nutrient-management-planning/

Why

Nutrient management plans help you to address the following key issues associated with fertiliser use.

Key Issue: Nitrate leaching to groundwater

Indicator: Increasing nitrate nitrogen in groundwater 

Nitrate leaching is not easily measured by users so the emphasis should be on avoiding leaching by following best management practices such as targeted nitrogen fertiliser application, animal grazing and dairy effluent irrigation rather than remedial action after it has occurred.

Possible cause Best practice
Nitrogen input exceeding nitrogen uptake

  • Reduce nitrogen input.

  • Increase nitrogen uptake in plants by matching nitrogen applications to plant growth (e.g., engage a technical field officer or agronomist for advice).

  • Ensure low or excessive pH is not directly or indirectly restricting N uptake (e.g., use soil tests to guide application)

  • Ensure pastoral growth is sufficiently abundant to cope with the uptake. Pasture should be at least 25mm high (approx. 1000 kg DM per ha) before nitrogen is applied with soil temperature above 5 degrees.

  • Balance nutrients (fertiliser inputs) (e.g., use soil tests to guide application)

  • Avoid application of N when the temperature is low and/or ground is waterlogged.

High nitrogen application rates (e.g. greater than 200 kg N/ha/yr)

  • Reduce nitrogen input.

  • Ensure high nitrogen uptake by:

    • Timing for growth periods

    • Splitting dressings (e.g., lower application rates more frequently)

    • Ensure appropriate placement

Applying nitrogen in a single application

  • Split the nitrogen applications so that smaller amounts are applied more frequently.

Heavy rainfall (i.e., >20mm within a day of applying N) or irrigation within a day of applying fertiliser

  • Check weather forecast and avoid application if heavy rain seems likely.

  • Avoid applying fertiliser when soil is above field capacity (i.e., puddles on the ground).

  • Select a less mobile nitrogen fertiliser (containing ammonium N rather than nitrate N).

  • Apply fertiliser after irrigation (e.g., border-dyke irrigation) especially when ground cover is low (>80%).

Permeable soils which can cause nitrogen leaching. (i.e., if puddles disappear quickly after heavy rainfall)

  • Apply smaller amounts of fertiliser more often.

  • Reduce the amount of nitrogen applied.

  • Select a less mobile nitrogen fertiliser (e.g., Ammonium N rather than nitrate).

Nitrogen fertiliser not securely stored

  • Ensure nitrogen is contained within the storage area on an impervious floor.

  • Protect stored N from rain.

High water table present

  • Reduce amount of N applied per application.
    Match application to plant uptake.

Contamination from loading sites

  • Ensure no spillage when loading in or out of storage, or into application equipment.

Key Issue: Contamination of surface water from fertiliser run-off

Indicator: Algal blooms and/or excessive weed growth in waterways from elevated nutrient levels.

Possible cause Best practice
Slope too steep for vehicle access or natural drainage lines running down to open water

  • Use slower release fertilisers, or split fertiliser applications. Apply smaller amounts more frequently.

  • Develop and maintain riparian strips.

  • Avoid applying fertiliser when the ground is saturated.

  • Increase buffer distance between application site and the open water.

High rainfall or irrigation within a day of fertiliser application

  • Check weather forecast and avoid application if heavy rain seems likely. Avoid irrigation in excess of field capacity.

  • Use slower release fertilisers or reduce the fertiliser application rates in wetter conditions.

  • Split the application rates. Apply smaller amounts more frequently.

  • Apply fertiliser after irrigation (in the case of, border-dyke irrigation) especially when the ground cover is low (>80%).

  • Check irrigation technique is appropriate for the crop.

Less than 80% ground cover (e.g., pasture less than 25 mm high or approx. 1000 kg DM/ha)

  • Increase ground cover before applying fertiliser.

  • Maintain resilient and productive ground cover that is capable of efficiently using the fertiliser.

  • Plant row crops on contour.

  • Ensure pasture is not over-grazed (reduce stocking rate or grazing time).

  • Avoid pugging damage.

  • Install and maintain riparian strips.

  • Surface incorporate, drill, or directly apply fertiliser to the root zone.

Saturated soils (puddles forming)

  • Delay fertiliser application until soil conditions improve.

  • Use a less soluble or slow-release fertiliser.

Excessive rates of application

  • Set realistic crop yield goals and apply fertiliser at times of maximum plant uptake.

  • Account for all sources of nutrients and apply nutrients in correct proportions.

Uneven application

  • Use equipment suitable for the conditions.

  • Use calibrated equipment and experienced operators.

Soil permeability low, soil cracking (macropores)

  • Improve soil draining characteristics (subsoiling).

  • Reduce soil compaction.

  • Reduce stocking rate.

  • Split fertiliser application rates. Apply less fertiliser more often.

Storage site too close (less than 50 metres) to open water

  • Improve the storage facility so that all fertiliser is effectively contained (under a roof).

Loading site too close (less than 50 metres) to open water

  • Minimise spillage of fertiliser when loading into or out of storage.

  • Move loading site away from open waterway.

Outflow from tile drainage system

  • Apply fertiliser when tile drains are not running.

  • Avoid application when soil is saturated.

Drought (excessively dry soils allowing high surface run-off because of slow infiltration rate)

  • Delay applying fertiliser until sufficient regrowth has occurred after rain.

Key Issue: Contamination of open water from direct application of fertiliser

Indicator: Algal blooms and/or excessive weed growth in waterways from elevated nutrient levels.

Possible cause Best practice
Aerial application

  • Use fertiliser with larger particle sizes (less wind effect).

  • Choose alternative aerial techniques to allow more precise placement (e.g., use of location maps using GPS and GIS).

  • Use methods other than aerial application.

  • Use selective application techniques (cover part of the area).

Ground application close to open water (e.g., less than 10m away)

  • Allow a larger margin between fertilised area and open water.

  • Use application techniques that direct or specifically place the fertiliser.

  • Use fertiliser with larger particle size.

  • Erect a physical barrier/riparian strip around the water.

Wind speed greater than 5km/hr towards open water

  • Apply fertiliser when wind direction is away from open water.

  • Use fertiliser products and application techniques that confine fertiliser to the target zone.

  • Change application techniques (e.g., drill fertiliser at planting rather than broadcast.)

Fertiliser particle sizes with poor ballistic properties (e.g. less than 1 mm in diameter for dry material)

  • Use fertiliser with larger particle sizes.

  • Use application techniques that direct or specifically place the fertiliser.

Storage site within 50 metres of open water

  • Move storage site away from open water.

  • Ensure the storage facility effectively contains the stored fertiliser (under a roof).

Fertiliser loading/handling operations less than 50 metres from open water

  • Relocate the loading site away from open water.

  • Use wind shelters around the loading site to contain fertiliser.

Key Issue: Social/ third party effects

Indicator: Complaints from affected parties

Possible cause Best practice
Use of dusty fertiliser

  • Use fertiliser with a larger particle size (dry material).
    Use other forms of fertiliser (e.g., slurry, liquids, or suspensions).

  • Ensure the wind is blowing away from sensitive areas.

  • Apply fertiliser only at agreed times.

Noise during fertiliser application

  • Change to quieter application equipment.
    Change time of day when fertiliser is applied.

  • Change operational technique to reduce effects of noise on affected parties.

  • Apply fertiliser only at agreed times.

Off-target contamination (solids and liquids)

  • Use fertiliser with larger particle size.

  • Use precise application techniques.

  • Apply fertiliser only when the wind direction is away from affected parties.

  • Apply fertiliser only at agreed times.