How is the weather forecast calculated? What do the colours of the application windows mean?

The algorithm analyses different field weather conditions and generates a recommendation for spraying and spreading. With hourly application windows, you know if the weather conditions in that field are suitable for spraying or spreading.


This is what the different colours mean:


WF-green.png Good conditions
WF-yellow.png Moderate conditions, be careful
WF-red.png Don't spray or spread
WF-grey.png Can't say for sure


Please note:

The recommendations aren't crop or season specific. Any recommendations are meant as a guide and must be adapted to suit local conditions.



Spraying application window




In general, dry periods are good conditions for spraying.



Wind speed


Wind speeds of less than 6.5 mph are good for spraying. Don't spray when the wind speed exceeds 10.1 mph.



Relative humidity


Avoid periods of very low humidity to ensure active stomata (small openings in the leaf surface). Very high humidity above 90% can reduce the effectiveness of sprays.



Air temperature


A good spraying condition is when the air temperature is between 7°C and 18°C. If the temperature is too low, the stomata will close and photosynthesis will stop. Too high a temperature will cause evaporation from the leaf surface.



Spreading application window


You can choose between 2 product categories to see the recommendations for spreading conditions:


  • High quality: granular and prilled fertilisers with good spreading characteristics
  • Low quality: granular and prilled fertilisers with sub-optimal spreading characteristics, for example, light urea prills, most blends, dusty products and some hygroscopic products





A short, light shower may be perfect for applying fertiliser. But a long, heavy rain will wash most of the fertiliser away. The algorithm looks at the soil moisture status and the rain events for the next 5 days to see if these conditions are met.



Wind speed


Strong winds can affect your spreading pattern, especially when spreading lighter prills.



Relative humidity


On a damp day, the fertiliser can absorb moisture, affecting flow rates. Damp or wet conditions also affect sulphur products, which build up on the vanes more quickly than in dry conditions.



Air temperature


High-quality products such as YaraBela™ Nitromag have a high nitrate content, which is also available at lower temperatures.

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