The risk of nitrogen leaching at autumn sowing decreases significantly if the crop is early established and if time is short between cultivation and seeding. If seeding is late, glyphosate treatment entails a significant risk of leakage, even in direct seeding. This is shown in recent research results from SLU.
In recent years, cultivation of autumn-sown crops has increased and caused demands for decision support on how to reduce nutrient leakage from these systems. At SLU we have examined which significance the length of the period between soil preparation and sowing has for the amount of mineral nitrogen (ammonium and nitrate) in the soil in the fall, and what that time span means in relation to the different processing methods. The amount of mineral nitrogen in the soil in the fall gives an indirect measure of the risk of leakage.