This step is very important to secure the yield and to insure an good harvest quality and an excellent oil quality. So it’s important to identity when sunflowers are around 8-9% of moisture to optimize the harvest, and so to anwers to famers and dealers needs.
HOW TO IDENTIFY THE BEST MOMENT TO HARVEST ?
THE OPTIMAL STAGE : 8-9% OF MOISTURE
The back of the head of sunflowers are changing color. They are becoming brown. Leafs in the down and the middle of stems are dry. There are a few leafs near the head still a little green. The stem is becoming brown too.
TOO EARLY : ABOVE 11% OF MOISTURE
Leafs in the middle and the top of stems are green. The back of head is still yellow. The humidity is over 11% of humidity. The risk, if you harvest at this stage, is to have to much impurities and an expensive cost of drying (+10% for a harvest at 15%). The harvest is complicated and slow.
TOO LATE : UNDER 8% OF MOISTURE
Leafs are totaly dry, the head is brown even black and sterms are brown too. If you harvest at this moment, you will loose an important part of yield (until 1T/ha for a harvest at 5%) because there will be lodging, shelling, birds attacks and disease attacks, and your oil quality will be deteriorated (too acid).
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