Wholecrop formula

[samsung]

I have 20 acres of S. Barley/Pea mix to wholecrop which I have already agreed the sale of, but we said we'd sort detail out nearer the time.
Is there a formula to follow to make it fair for both parties.
Probably linked to analysis including DM and fresh weight ?

 

[harperfarmer]

Last year I sold surplus standing crops for £0.85 per % dry matter per ton and they stood the harvesting costs. So for example oats wholecropped at 32%DM would be £27.20/t x freshweight yield (last year we averaged 16t/acre, this year be lucky to do 10t). I was happy with that.