Canadian Agriculture. 
229 
to make a few extracts. Besides the three soils aheady referred 
to, four other Manitoba soils were examined in greater detail. 
They came respectively from Niverville, 44 miles west of 
Winnipeg; from Brandon, loo miles west of Winnipeg; Irom 
Selkirk, 22 miles north-east of Winnipeg ; and from Winni- 
peg itself. These soils showed a very high percentage of 
nitrogen ; that from Niverville nearly twice as high a percent- 
age as in the first 6 or 1) inches of ordinary arable land, and 
about as high as the surface soil of pasture land in Great 
Britain. That from Brandon was less rich, still the first 12 
inches of depth is as rich as the first 6 or 9 inches of good old 
arable lands. The soil from Selkirk showed an extremely high 
percentage of nitrogen in the first 12 inches, and in the second 
12 inches as high a percentage as in ordinary pasture surface 
soil. Lastly, both the first and second 12 inches of the Winni- 
peg soil were shown to be very rich in nitrogen, richer than the 
average of old pasture surface soil. To determine to what 
extent the nitrogen in these soils is susceptible of nitrification, 
and so of becoming available for plant-growth, the soils and 
subsoils were placed in shallow dishes, covered with plates of 
glass, kept under proper conditions of temperature and moisture 
for specified periods, extracted from time to time, and the nitric 
acid determined in the extracts. The periods were never less 
than twenty-eight days, and the rate of nitrification declined 
after the third and fourth periods. In the case of the subsoils, 
there was a very marked increase in the rate of nitrification 
during the eighth period as compared with the seventh, there 
having been only a tenth of a gram of garden soil containing 
nitrifying organisms added. This result is very striking, and 
of much interest, affording evidence that the nitrogen of subsoils 
is subject to nitrification if only in suitable conditions, and the 
result lends confirmation to the view that deep-rooted plants 
may favour nitrification in the lower layers of the soil. 
The authors further state that official records show that the 
rich prairie soils of the North-West are competent to yield 
large crops, but under present conditions they do not give 
yields commensurate with their richness, compared with the 
soils of Great Britain, which have been under arable culti- 
vation for centuries. That the rich prairie soils do not yield 
more produce is due partly to climate, but largely to scarcity of 
labour, and consequent imperfect cultivation, thus leading to 
too luxuriant a growth of weeds ; and until mixed agriculture 
and stock-feeding can be had recourse to, and local demand 
arises, the burning of the straw, and deficiency and waste of 
manure, are more or less inevitable, but still exhausting practices. 
So long as land is cheap and labour dear, some sacrifice of 
