Three horse land they used to call it, since it was so tough you needed 3 to pull a plough instead of the usual 2.
Can't imagine drilling crops in the rain on our Essex clay, either . . . the whole outfit would have been one huge ball of clay in minutes.
The people were certainly a good deal fitter than most of us today . . . but I think many more were worn out, bent and crippled in later years

Mike.