That photo has to be staged. Who (in their right minds would leave that many boxes on a hive? From a safety point alone, there is a danger that he could fall or that the stack should topple over.
I guestimate 30Kg of honey per deep langstroth box. Sometimes a little more, sometimes a little less. Its just a rule of thumb I use (its usually 30-35Kg). This means that 150Kg would require 5 deep boxes plus 2-3 brood boxes. Now, those 5 boxes probably wouldn't be left on all season (at least not if there was OSR nearby) so, realistically, the stack should be no bigger than 4-6 boxes in total (2-3 for a large brood area plus 2-3 for honey supers).
First, Langstroth box has 25 kg honey to be extracted. Medium has 15 kg. I have read, that 20% out of honey will be stay in combs after extracting (=5 kg).
Then one capped box needs 2 more boxes for nectar.
To get 150 kg you should extract the hive at least 3 times. More times is better to store nectar.
To get 150 kg, the colony must get 50 kg in June and 100 kg in July. If the colony is not strong enough in June, it cannot catch any more the missing yield in July. Every day in month cannot be good, it they are, nature will wilt.
B+:
the stack should be no bigger than 4-6
That size hive is not able to store 150 kg honey into the hive, because it cannot store nectar in short blooming. The hive needs 7-8 langstroth boxes, and then, it needs very good queen on previous summer.
When rape blooms 2 weeks, and a hive can forage 5 kg a day, it is 70 kg,
My maximum yield from pure rape are 60 kg. If you do not move the hives from rape, they perhaps do not have other pastures. Fireweed pastures can give double that yield.
To get 150 kg from a hive it needs 6 weeks good weather and some day heavy short rains. If I have only 3 good weeks, the yield is then 60-80 kg.
5 kg a day is good, and 30 days x 5 = 150. Our maximum yield time is 6 weeks. Some year only 1 week.
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