Yield of Wheat. 



13 



retraction or modification made by Dr. Saunders of his " reasonable 

 prophecy " of 1904 that wheat grown on one-fourth of the land 

 suited to it in the Canadian North-West with the yield of Manitoba 

 in the previous decade would bring a crop of more than 

 800,000,000 bushels. If there be such a surplus of good soil as 

 three-fourths, ample room would be left for diversified crops and 

 such rotations and following as might be needful in future years 

 to meet the declining production of the prairie soils. 



After a reference to Sir William Crookes' forecasts in 1898, and 

 the extent to which later data had outstripped his modest expecta- 

 tions, Professor Brigham declared it " hazardous " to set limits 

 to wheat in view of possible unknown factors of production. 



Sufficient account had not been taken of the limitation of 

 population among the nations of the higher standards, who are 

 bread-eating peoples. Any pressure on the wheat supply would 

 foreshadow itself before the pinch came, and would tend to still 

 further restriction of population. He agreed with an earlier con- 

 clusion of an American economist (Mr. D. A. Wells) that the 

 world " for the first time in its history has now good and sufficient 

 reasons for feeling free from all apprehensions of a scarcity or 

 dearness of bread." Any increased demand in W T estern Europe, 

 or more truly in North-Western Europe, would be fully met by 

 developments in Canada, Russia, Argentina, Egypt, India, South 

 Africa, and Australia, so that they might even leave out the 

 United States, or even omit India should her wheat be needed at 

 home to avoid periods of famine. Argentina was as yet 

 undeveloped, and Russia backward in bringing her vast resources 

 to full effect on the world's market. North America had the land, 

 progressive appliances, skilled energy, and facilities of transport 

 to supply the bread market of coming decades. No citizen of the 

 United States of America need harbour a jealous thought if in 

 that market a major place should come to her northern neighbour. 



II. 



THE FACTORS DETERMINING THE YIELD OF WHEAT. 



By A. D. Hall, M.A., F.R.S., and E. J. Russell, D.Sc 



The Rothamsted experiments on wheat began in 1843 on the 

 Broadbalk field on which wheat has been grown every year since. 

 In the first few years a general idea was obtained of the require- 

 ments of the plant as regards manure ; a scheme for the treatment 

 of the plots was drawn up in 1851, and has been substantially 

 adhered to ever since. 



(1) Food. — The chief elements of nutrition derived from the 

 soil or manure are nitrogen, phosphoric acid, and potash ; lime, 



B 



