A nitrogen mass balance budget is a method to determine how much nitrogen fertiliser should be applied to the crop to achieve its potential yield. However, for the budget to be developed, estimates are required for the crop’s demand for nitrogen and how much of this will be supplied by the soil.
Currently, there are two tests used to quantify soil nitrogen supply.
- The mineral N test, which provides a measure of how much nitrogen is immediately available for plant uptake.
- The anaerobically mineralisable N (AMN) test. This is an estimate of the N supply from the mineralisation of organic N.
For an effective nitrogen mass balance, both sources of nitrogen need to be measured. An AMN test can be done annually but the amount of mineral N in the soil can change quickly over a short period of time, especially as crops take up nitrogen. Quick N tests strips can be used at any point in the rotation to give a real-time snapshot of the mineral N levels in your soil
The QTMB Tool and User Guide show you how to:
- Measure the soil nitrogen supply with nitrate quick test strips.
- Use the test-strip result to make an informed fertiliser decision for the crop.