What are the risks of too low Delta T?
Increased potential for drift due to long droplet survival.
Spray mix will not run off plants/leaves because of dew or fog.
Avoid spray treatments during calm wind conditions – the inversion layer increases risk for drifts.
A low Delta T value (under 2) indicated that the relative humidity is high, which can cause spray droplets to remain hanging in the air for longer periods of time. This can lead to unintended drift due to increasing wind/weather changes.
To minimize the risks associated with low Delta T values, it's important to avoid applying crop treatments when conditions are not suitable.
What are the risks of too high Delta T?
Increased potential for little droplet survival in the air
Evaporation rate: Spray droplets will evaporate off the plant leaf before it has time to have any effect on plant tissue.
Stressful situations for applying herbicides.
Avoid values greater than 10°C.
Avoid spraying in air temperatures above 28°C.
When Delta T is high (above 12), it means that the air is hot and dry, which can cause the spray droplets to evaporate quickly before they either reach the plant/leaves or before they can unfold their effect on the plant. This can reduce the effectiveness of the treatment and result in poor coverage.
In addition, high Delta T values can also increase the risk of spray drift. The dry air can create air currents that can carry the spray droplets away from the plants.
To minimize the risks associated with high Delta T values, it's important to avoid applying crop treatments during the hottest and driest parts of the day when the Delta T value is likely to be highest. Also, you may want to choose appropriate nozzles and spray patterns that can help to reduce drift and improve the coverage of the crop.