I cant plough for toffee, but I thought the following information would be of interest to those that can.I have just got a copy of “The Vegetable Growers Guide” by Chas, Oldham, from 1950 he quotes an experiment in Dorset, by the National engineering institute, this demonstrated that a Rusty two furrow plough required an additional 245 LB of pull, equal to 122 LB of pull EXTRA for a single furrow compared to a plough with a bright mouldboard, he also mentions that for every extra 150LB of pull, the tractor must develop another one horsepowerI knew it was important, but interesting to see that the fault was measured.