Thats a seed pollination contract type density (it can go as high as 20) and is pretty well a guarantee of getting nothing.
It is some year since the work was done (actually maybe 25 years and on older more bee friedly varieties than today) but it was stated that you should aim for between one hive per acre and one hive per hectare. The latter figure seems a bit light and was to ensure that even strong colonies did not run out of available nectar, and the former figure of one per acre was to give the farmr decent pollination but above that and your honey crop drops off.
So many variables including weather, timing, bee power, variety etc, but a fair compromise that gives you what you need and the farmer what he needs would be about 1.5 to 2 hives per hectare.
If the farmer brings you in to achieve crop uplift on his osr then you need to ensure that you arrange enough bees for him/her or it would be a reasonable response to a shortage for them to invite in additional bees. Any fair minded beekeeper would take account of your presence and either keep away or calculate their hive numbers to accommodate your forage needs. Only a few have the attitude that they would try to squeeze you out. In my book there is always a space for the small beekeeper.
