Key points

• Deep N testing during the crop tillering stage helps to understand N pool available to plant for growth, taking into consideration mineralisation of organic matter
• Complete deep N testing at or just prior to crop growth stage 31, typically mid to late July depending upon the time of sowing and emergence
• Fertiliser N application levels depend on the nitrogen demand of the crop (target yield and grain protein) and N supply remaining in the soil.
• Take six deep cores down to approximate rooting depth to get a representative sample of the soil N profile.
• Keep samples cool and dispatch for testing as soon as possible to ensure mineralisation does not occur within the bag.
• By ensuring N is applied during the season, this reduces the reliance on N mining from the soil reserves during spring.