Vol. XII. Part 2 



April, 1922 



THE 



JOURNAL 



OF ' 



AGRICULTURAL SCIENCE 



EDITED FOR THE PLANT BREEDING AND ANIMAL NUTRITION RESEARCH INSTITUTES AT CAMBRIDGE, 

 AND THE ROTHAMSTED RESEARCH INSTITUTES BY 



Professor R. H. BIFFEN, M.A., F.R.S., Cambridge 



Sir a. D. HALL, K.C.B., M.A., F.R.S., Ministry of Agriculture, London 



F. H. A. MARSHALL, Sc.D., F.R.S., Cambridge 



E. J. RUSSELL, D.Sc, F.R.S., Rothamsted Experimental Station, Harpenden 



Professor T. B. WOOD, C.B.E., M.A., F.LC, F.R.S,, Cambridge 



IN CONSULTATION WITH 



B. C. ASTON, Department of Agriculture, Wellington, New Zealand 



Dr C. a. barber, C.I.E., School of Agriculture, Cambridge. . 



Professor B. T. P. BARKER, M.A., National Fruit and Cider Institute, Long Ashton, Bristol 



W. BATESON, M.A., F.R.S., John Innes Horticultural Institute, Merton, Surrey 



J. R. CAMPBELL, B.Sc, Department of Agriculture, Dublin 



I. B. POLE EVANS, Department of Agriculture, Pretoria, South Africa 



F. B. GUTHRIE, Department of Agriculture, Sydney, N.S.W. 



Professor J. HENDRICK, B.Sc, Marischal College, Aberdeen 



Sir T. H. MIDDLETON, K.B.E., C.B., M.A., The Development Commission, London 



Dr frank T. SHUTT, F.I.C, Experimental Farms, Ottawa, Canada 



Professor W. SOMERVILLE, M.A., D.Sc, School of Rural Economy, Oxford 



Dr a. C. true. Department of Agriculture, Washington, D.C., U.S.A. < 



Sir FRANCIS WATTS, K.C.M.G., Barbados 



Dr H. J. WHEELER, American Agricultural Chemical Co., Boston, Mass., U.S.A. 







Cambridge University Press 



C. F. Clay, Manager 



London : Fetter Lane, E.C. 4 



also H. K. Lewis & Co., Ltd., 136, Cower Street, London, W. C. t 



and Wheldon and Wesley, Ltd., 28, Essex Street, London, W.C. 2 



Chicago : The University of Chicago Press 



(Agents for the United States and Canada) 



Bombay, Calcutta, Madras: Macmillan and Co., Ltd. 



Tokyo: The Maruzen-Kabushiki-Kaisha 



^rice. Ten Shillings net 



{Issued 30 May, 1922.] 



