Rainfall events do occur during droughts. Whilst these events may not be of sufficient intensity and occurrence to wet the profile for sowing a crop, they appear to be enough for microbial-induced mineralisation. While mineralisation occurs in a burst of activity, the cumulative effect is a soil rich in nitrate.

Key points discussed include:

• Soil-nitrate increases following a drought.
• Enough rain falls during a drought for mineralisation to occur.
• After drought, soil sampling is the most reliable method for determining soil-nitrate levels.
• To determine a fertiliser rate, soil-nitrate levels need to be balanced with target yield and protein.