Mid-row banding promising for in-crop Nitrogen

Mid-row Banding (MRB) places nitrogen (N) fertiliser below the soil surface in every second crop inter-row. Recent research looked at using MRB for in-crop N applications. In-season N applications aim to meet a crop’s peak N demand and improve the efficiency of crop uptake. MRB can reduce some risks that go with in-season N applications and could help improve the return on investment for in-crop N application.  

Mid-row banding looks promising

Some potential advantages from MRB fertiliser applications include:

  • Reduces N losses from volatilisation. Placing N below the soil surface reduces the risk of ammonia loss to the atmosphere.
  • Reduces the need for rainfall following N applications. Surface applied N relies on rainfall to wash N into the soil profile.
  • Holds nitrogen in the ammonium form for longer. Microbes are slower to convert fertiliser N placed in concentrated bands to nitrate. This reduces the extent of potential N losses through denitrification, and/or nitrate leaching from the root zone.
  • May reduce microbial tie-up of applied N. Organic matter and soil microbes are often concentrated near the soil surface. Deep bands of N can reduce immobilisation to a greater extent than surface applied N, particularly where stubbles are retained.
  • Could help meet the 4R’s (right type, right time, right place, right rate). MRB can help apply N fertiliser at the right time and, in the right place.

Mid row banding trials in Victoria

In-crop N application methods were tested at sites in the Victorian Wimmera and Mallee. Results from 2016 trials showed that MRB application of N:

  • Improves yield, with an extra 0.2–0.5 tonnes of wheat per hectare on average. That’s compared to different methods of application, and equivalent to approximately 4–12% yield gain.
  • Improves uptake efficiency, with fertiliser-N uptake on average 46% higher. This is averaged across timing and rate of application.

 

Researchers continue to monitor trials through 2017 to validate these results.

More information

GRDC:

Mid-row banding nitrogen fertiliser in-season

ExtensionAUS:

Three reasons why topdressing nitrogen can fail

What happens to urea with high residue loads

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