THE 



JOURNAL 



OF 



AGRICULTURAL SCIENCE 



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

 AND THE ROTHAMSTED RESEARCH INSTITUTES BV 



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



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



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



Sir 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 W.'iTTS, K.C.M.G., Barbados 



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



VOLUME XII 1922 



CAMBRIDGE 



AT THE UNIVERSITY PRESS 

 1922 



