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N-rich strips show if your crop needs a boost this season

An N-rich test strip in a canola crop at Branson Farms, South Australia.


An N-rich test strip in your paddock allows you to follow nitrogen supply in-crop, and see what responses are likely to additional N. The test strip is a part of the paddock where additional N is applied – above the base rate applied to the rest of the paddock.

Crop areas in and out of the strip have the same amount of mineralisation and are exposed to the same environmental conditions. Any differences can be reasonably attributed to the higher N supply in the strip.

The N-Rich strip will show what response could be expected from additional N fertilizer in this paddock, in this season. A strip will also show when additional N is not required at all.

The strips give me the confidence ‘Not to apply N’ when the crop is N sufficient. This has saved me a lot of $$$$ over the years.”

– Mark Branson, grain grower, South Australia.

Guidelines for using a strip

  • Run a strip across a typical part of the paddock. Use GPS to record the position, and / or some visual markings in the paddock. If the paddock is zoned for different N management strategies, then run the strip across these areas so that the responses can be seen in all zones.

  • Apply an additional 50 to 100 kg N/ha to the strip just before or after sowing. Use a combine or air-seeder width (solids) or a boom spray (fluid). You can do a strip up the paddock and then overlap half the width coming back to give two rates.

  • Assess the strip at the very start of stem elongation. Applications of topdressed N are likely to be more effective in increasing yield at stem elongation than later.

  • Monitor visually or using NDVI devices. If no differences can be seen between the strip and the rest of the paddock then the added N did not give a response. The strip provides confidence in a decision not to apply N. If a response is seen, then a response to added N is likely.

  • Spread later N applications over the N-Rich strip as well. Then the strip will continue to indicate any potential response to more N.
  • More information

    Much of the development of N rich test strips as tools to inform fertiliser rates comes from Oklahoma in the USA, a few of these resources:

    An online calculator based on the difference between the NDVI value of the N Rich strip and the untreated strip and days from sowing – comes up with a recommendation of the N rate to be applied.

    A video with Dr Brian Arnall from Oklahoma State University on how they are using a sensor over N-Rich strips linked to the online calculator to develop N recommendations.

    A video on the how what when & why of N rich test strips, also with Dr Brian Arnall.

    Also more detail on the IPNI Australia & New Zealand website – Time for an N rich strip


    Rob Norton, IPNI, Kate Wilson, Agrivision, Alli Elliot, BCG, Mark Branson, Branson Farms.
    Image courtesy of Branson Farms.

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