Its the second fastest growing plant in world
SOWN in early May with a conventional drill, hemp is ready to cut by mid-August with virtually no work in between.
Seed and fertiliser, 80-90kg/ha of nitrogen, are the only inputs required, and even on less fertile land a forest of 2-3m tall growth is produced within 90 days.
Cutting is with a disc mower or forage harvester, the crop retting and drying faster if chopped into 30-50cm (12-20in) lengths.
The retting process allows bacteria to break down the pectins that hold the fibre to the hurds and takes about a fortnight in the field, during which time the crop should be turned at least once.
It is then baled and carted for storage. Usual yield is 7t/ha (2.8t/acre) of dry biomass but up to 20t/ha has been known, says Mr Bielby.
"It is the second fastest growing plant in the world. Only bamboo beats it."
Once harvested stubbles must be left for a month before ploughing to allow government inspectors to verify the crop has been harvested. But it should still be possible to establish a winter wheat crop by mid-October.
"Some growers in Cornwall have even tried triple cropping with hemp, sowing after new potatoes in the spring and following with a brassica vegetable in the autumn."
Area payment, expected to be the same as for cereals and set-aside in 2002, is paid only if and when the crop is processed. "Clearly that would be within growers control if processing on-farm."
But to claim processing subsidy, straw and processed fibre must be put over a weighbridge – another policy that has hindered on-farm processing, notes Mr Bielby.
"Unfortunately, it means at least one pointless round-trip to a weighbridge." *