ABSTRACT
Weigh say six bales in a bay, preferably from different layers and get average weight in kgs. Count number of bales, multiply weight by number of bales and divide by 1000 = number of tonnes, eg 920 bales average 20.4 kg in bay:
920 × 20.4/1,000 = 18.768 tonnes
Volume method
Sometimes it is not possible to count bales. An alternative method is to obtain the cubic content of the stack in m3 and divide by an appropriate density figure:
Very compact: 6-7 m3 per tonne Medium: 8-9 m3 per tonne Unsettled: 10-11 m3 per tonne
Practice checks
Small bales of hay often approximate at 50 bales per tonne. Medium and heavy bales often weigh from 18 to 22 kg per bale. Discount any weathered bales on the exposed side of barns and also possibly half or sometimes the whole of the bottom layer as this might be damp. Look out for voids in the stack. The bottom layer has usually more bales than the other layers since they are laid on edge. As a rule a bay 24ft (7.3m) × 15ft (4.5m) × 18ft (5.4m) will contain approximately 20 tonnes.
3.2.1.2 Big bales
