G. V. DYKE, B. J. GEORGE, A. E. JOHNSTON, P. R. POULTON and A. D.TODD (1983) The Broadbalk Wheat Experiment 1968-78: Yields and Plant Nutrients in Crops Grown Continuously and in Rotation in : Rothamsted Experimental Station Report for 1982 Part 2 - pp 5 - 44