Will low protein become the new norm?
Take home messages
- Soil tests from throughout the region in 2012 indicate that soil mineral N contents were low in comparison to years prior to 2010, which may help explain why grain proteins were generally low in 2012.
- Mineral N contents were low primarily due to high rates of N removal (in grain) in the previous seasons. Denitrification may also have contributed to lower mineral N levels; however this is hard to clearly define.
- There has been a reduction in the number of paddocks tested for N in recent seasons and this may be contributing to poor nitrogen decisions.
- There were exceptions to the “11% protein rule of thumb” in 2012 where maximum grain yields were achieved at grain protein concentrations between 9-10%.
- N fertiliser recovery in grain was moderate at best in 2012 VSAP trials.
- Longreach Spitfire has been observed to have a grain protein concentration advantage over other varieties at a given yield level; however, the effect of variety choice on grain protein concentration is small compared with the effects of agronomic management.•
- Based on a range of trials and varieties that had plus or minus crown rot treatments the impact of crown rot on grain protein concentrations was negligible.
- To ensure N does not become a major factor limiting yield, N supply needs to be enhanced using a combination of legume crops/pastures and tactical fertiliser N applications.