Quand faire le premier apport :Double Density Band Method
From Triple Performance
Trigger nitrogen nitrogen applications in crops using decision rules based on indicators such as the stage, a number of days... to match the applications to the crop's periods of need while taking into account climatic conditions, and thus maximize the efficiency of nitrogen uptake by the crop.
Challenges
Matching applications to periods of high demand and favorable conditions for optimal utilization by the crop can be tricky. Periods of high demand may coincide with unfavorable conditions for application effectiveness:
- High rainfall accumulations;
- Droughts;
- Conditions favorable to volatilization...
The double density strip (DDS)
The double density strip (DDS) method is a simple, reliable, and visual indicator to know when to trigger the first application.
- Principle: choose a representative area of the plot and double the seeding density on a strip 30 m long and 3 to 6 m wide at sowing. Doubling the number of plants will lead to higher and earlier nitrogen consumption on this strip than on the rest of the plot. One method to obtain a double density strip is to reseeding diagonally across the plot. Doubling the density on the same seeding line by opening the seed drill distribution is not the best option because the density obtained this way is not truly doubled.
- Triggering the first application: it should be done as soon as a discoloration of the double density strip compared to the rest of the plot is observable. This method helps improve the apparent use coefficient (AUC) of the application by limiting gaseous losses that can occur if the application is made outside periods of high crop uptake.
Sources
Using decision rules to define nitrogen application dates, 2018, GECO
