If we ever needed a reminder that nitrogen (N) deficiencies could be widespread this year, than the images below are perhaps all we need.
They highlight the sharp drop in soil nitrate-N levels from last year - courtesy of a bumper crop for most of the State and limited mineralisation of organic N since.
The red dots signify samples with less than 5 mg/kg nitrate N – equivalent to less than 6 to 8 kg of N/ha in the top 10cm. When it rains, we will get more N from mineralisation of organic matter, but the this will be limited by low organic matter levels and cooler temperatures. All of these factors will make us more dependent on N fertiliser at seeding in order to get good crop establishment.
None of this should come as any surprise. Just a reminder to be prepared to use more N at seeding.
Soil nitrate N measured in 0-10cm samples in the 2017/18 and 2018/19 soil sampling seasons.