Key points
- The Quick Test Mass Balance approach is an effective method for informing in-season nitrogen (N) management decisions for maize growers.
- Nitrate Quick Test strips can be used to estimate mineral N levels in the soil at any time during the crop’s growth. They may be used as a cost effective substitute for the mineral N test, particularly for top soil samples (0–30 cm depth), where nitrate-N is the predominant form of mineral N.
- Quick Test estimates of soil mineral N levels can be used for fertiliser mass balance calculations to inform in-season N management decisions for the crop.
- The mass balance calculation for a side-dressing decision is: N FertSD = [Crop NTotal – Crop NSD]
- Soil Min NSD – Soil Org N mineralised. Information about the potential crop demand and the soil nitrogen supply is required.
- The mass balance calculation can either verify the fertiliser plans for the crop are correct, or support less fertiliser being applied, e.g.at site 2 in this trial. It can also indicate that more fertiliser should be applied to reach the potential crop yield.