Best management practices for nitrogen use

Activity

Best management practices

Choice of fertiliser

  • Use Fertmark registered products
    Fact Sheet 4

Rate of fertiliser application

  • Nutrient application rates are determined using some or all of the following factors:
    Fact Sheets 2, 5, 7, 8
    • soil and plant tissue analysis
    • nutrient budgets (including any effluent and/or feed imported to the block)
    • crop type, yield/quality/stocking rate targets
    • the need for capital or maintenance applications
    • previous crop and fertiliser history on the site
    • soil moisture conditions and expected future weather patterns
    • local knowledge
    • feed budgeting/monitoring
    • soil temperature
  • The amount of nitrogen applied per application is limited:
    Fact Sheets 8, 9
    • on soils where groundwater lies under permeable sediments (e.g. gravels)
    • in areas where there is a high water table
    • on areas where there is subsurface mole and tile drainage
  • Apply nitrogen fertiliser in split dressings of 50kg N/ha when 200kg N/ha or more is required
    Fact Sheets 6, 8, 9
  • Nitrogen is applied in proportion to other nutrients, according to plant requirements. (Adding excessive N when other elements limit crop or pasture growth leads to greater N losses.)
    Fact Sheet 5

Application technique

  • Application equipment is suitable for the conditions and fertiliser type.
    Fact Sheets 3, 4
  • Only Spreadmark accredited spreading companies (experienced operators and calibrated equipment) should be used
    Fact Sheet 4
  • GPS and GIS technology is used for precise application and for a digital record of fertiliser application locations.
    Fact Sheet 3
  • Non-target application of fertiliser is avoided by:
    Fact Sheets 3, 4
    • using fertiliser with larger particle sizes (mean size greater than 1mm) and few or no fine particles
    • application techniques that direct or specifically place the fertiliser appropriately
    • application in bands when sowing crops or pasture seed
    • choice of fertiliser types that can be applied more precisely (e.g. slurry/liquid)
    • applying fertiliser only when any significant wind is blowing away from sensitive areas
    • fertiliser is not applied by air when wind speed exceeds 15 km/hr

Frequency of application

  • Nutrient availability is matched to plant demand.
    Fact Sheets 6, 8
  • Lower rates of N fertiliser are applied more often, at times to match the growth cycle of the crop or pasture and soil moisture conditions, rather than in single large applications.
    Fact Sheets 6, 7, 8

Timing of application

  • Nitrogen application is matched to times of high plant growth.
    Fact Sheets 7, 8
  • Pasture is at least 25mm high (approx. 1000 kg DM/ha) before nitrogen is applied.
    Fact Sheet 9
  • In the case of border-dyke irrigation fertiliser is applied afterwards, provided the soil is not saturated. If the soil is saturated fertiliser application is delayed until ground conditions are suitable.
    Fact Sheet 9
  • Nitrogen is not applied when the 10cm soil temperature at 9am is less than 6ºC and falling (at these low soil temperatures plant nitrogen uptake is slow and there is greater risk of leaching loss).
    Fact Sheets 6, 9
  • Nitrogen is not applied after a dry (drought) period until sufficient regrowth has occurred after rain.
    Fact Sheet 9
  • Where possible, fertiliser N application is adjusted to complement the release of soil mineralisable N.
    Fact Sheets 6, 9
  • For information about the effects on stock of high nitrate in grass (link to Wise N use fact sheet PDF) contact Fert Research for a Wise N Use fact sheet (Code print version only).
  • N fertiliser is not applied in mid to late autumn to fallow land unless there is a cover crop.
    Fact Sheet 9
  • N fertiliser is not applied when the ground is saturated and/or when tile drains are running.
    Fact Sheet 9
  • N fertiliser is applied 4-6 weeks before the feed is required.

Fertiliser use and management measures

  • N fertiliser is not applied to severely compacted soils. Soil aeration techniques are used on such soils before fertiliser application.
  • Pasture is at least 25mm high (approx. 1000kg DM/ha) before N fertiliser is applied.
    Fact Sheet 9
  • Vegetated riparian buffer strips of sufficient width (10m - adjust for slope) to filter any run-off are maintained adjacent to all waterways.
  • Urease inhibitors - can be used to reduce urea losses to the atmosphere when conditions are conducive to volatilisation.
  • Nitrification inhibitors can be used:
    Fact Sheet 11
    • either with the fertiliser N or
    • applied across the whole area to help reduce nitrogen leaching from urine patches.

 

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