SECTION M.—AGRICULTURE. 
PRESENT-DAY PROBLEMS IN 
CROP PRODUCTION. 
ADDRESS BY 
SIR E. JOHN RUSSELL, F.RB.S., 
PRESIDENT OF THE SECTION. 
THE visits of the British Association to Canada have hitherto very appro- 
priately coincided with definite stages in the progress of agricultural 
science and practice. It was at the Montreal Meeting of 1884 that Lawes 
and Gilbert presented their well-known paper on the sources of the fertility 
of Manitoba soils which ended the first great period of the development of 
agriculturalscience. This periodhad lasted eighty years; it had been ushered 
in with the precise and scientific work of de Saussure published in 1804 ; 
its outstanding features had been the foundation of agricultural science 
by Boussingault in 1834, its enrichment by Liebig’s brilliant essay of 1840, 
and its systematic development by Lawes and Gilbert at Rothamsted 
from 1843 onwards. The whole purpose of the scientific workers of the 
period was to feed the plant; in Gilbert’s own words the message of the 
crops on the Rothamsted plots was, ‘ If you won’t feed us we won’t grow.’ 
The success of the new science was remarkable ; its great triumph was the 
discovery of artificial fertilisers and their introduction into farming practice, 
and the workers had the great joy of seeing the crop yields rise considerably 
as the direct and recognised result of their labours. The problems were 
largely chemical, and agricultural science was regarded as simply a branch 
of chemistry. Gilbert’s paper in 1884 was read before the Chemical 
Section, and it presented soil fertility as essentially chemical; a fertile 
soil, he argued, is one containing much plant food, especially nitrogen ; it 
is one ‘ which has accumulated within it the residues of ages of natural 
vegetation, and it becomes infertile as this residue is exhausted.’ At the 
time of the Toronto Meeting in 1897 a new period had begun, quietly 
and unnoticed, but growth was so rapid that at the Winnipeg Meeting in 
1909 the subject had grown right away from chemistry ; it had become a 
definite subsection, and its importance was so widely recognised that a 
recommendation was passed asking the Council to set it up as a full section, 
which was subsequently done. 
In this second period the purpose was not to feed the crop but to study 
it ; to discover what factors are concerned in the growth of crops and how 
they operate. This period, which may be called the period of free explora- 
tion, since the workers were not usually tied down to any particular tech- 
nical problem, began almost simultaneously in the United States, in France, 
and in Germany. As soon as agricultural science was studied in the 
United States it became evident that the cultivation of the soil was at 
