The pair presented to growers at last week's East Midlands Potato Day research they had gathered on the cost per hectare of both traditional and alternative fertilisers.
They revealed that poultry litter, cattle farmyard manure (FYM), cattle slurry and green compost are all good value for money. Green compost was the cheapest out of the four - averaging £198/ha, with most of its value coming from its potash value of 195kg/ha.
Chambers said: "Green compost is a good alternative so it's worth working with a local composter."
Cattle FYM averaged £380/ha, cattle slurry £342/ha and poultry litter £363/ha.