Deep Soil Nitrogen (DSN) Testing

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Early rainfall whilst soil temperatures were still warm, will have led to significant mineralisation of Nitrogen in most paddocks. Mineralisation rates of up to 1.0 kg/Nitrogen/ha/day are likely, resulting in up to 50 – 60 kg N/ha (110 – 130 kg Urea equivalent) being mineralised prior to sowing. With such mineralisation, the requirement for topdressed Nitrogen is likely be reduced during 2014. In order to make such decisions with more certainty, accurate soil Nitrogen data from DSN tests is required.

DSN tests should be taken during late May/early June to facilitate planning of Nitrogen topdressing. Most effective results will be achieved by:

  • Testing a representative number of paddocks

  • Testing paddocks that are expected to be both high and low in Nitrogen status

  • Where possible testing the same paddocks over a number of years in order to establish a trend over time

  • Testing to 90cm depth

  • Taking tests early so that results are received in a timely manner before topdressing decisions are made

CroppingLiz KelleherRural Management Strategies