3 0' 



b 



THE 



JOURNAL 



OF 



AGRICULTURAL SCIENCE 



EDIl'ED BY 



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



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



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

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



IN CONSULTATION WITH 

 Dr H. p. ARMSBY, State College, Pennsylvania, U.S.A. 

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

 Dr C. a. barber. 



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 

 1. 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 

 J. W. LEATHER, V.D., F.I.C., Major 



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



F. T. SHUTT, M.A., 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. 



Dr FRANCIS WATTS, C.M.G., Barbados 



Dr H. J. WHEELER, American Agricultural Chemical Co., Boston- Mass. 



VOLUME IX 19 18—19 



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. i 



and William Wesley & Son, 28, Essex Street, London, W.C. 2 



Chicago : The University of Chicago Press 



Bombay. Calcutta .and M.adr-\s : Macmillan and Co., Ltd. 



Toronto; J. M. Dent and Sons, Ltd. 



Tokyo : The Maruzen-Kabushiki-Kaisha 



[-4// riiihts rc/iervcil] 



