Influence of Climate on Cultivation. 
489 
crop. In their experiments, recorded in the eighteenth volume 
of this Journal, they find, *' Other things being equEi], the later 
the barley is sown the less should be the proportion of nitrogen 
in the manure, and the greater that of mineral constituents : 
otherwise the crop is liable to be too luxuriant. ' These expe- 
riments, therefore, we need scarcely add, indicate that the leaves 
of the barley have greater powers of appropriating ammonia 
from the atmosphere during the warmer season. The uniformity 
of Xature in the production of phenomena is well known, and 
what Mr. Lawes has found in the case of barley is exhibited 
under parallel circumstances by all crops, in a less or greater 
degree. 
Mr. Harris finds that superphosphate of lime has a much 
gieater effect on Chinese sugar-cane than on Indian corn. This 
substance produced a wonderful increase of grow th on the cane, 
inasmuch as the plants on the manured plot rose to the height 
of ten feet, while those on the unmanured plot were not five feet 
high.* 
In all warm climates the effect of applications of phosphates, 
»S;c., to vegetables is greater than in cool, for two reasons : — First, 
plants grown under a high temperature have greater powers of 
taking ammonia from the atmosphere, and thus are less dependent 
on a supply within the soil ; and, secondli/, the existence of rapidly 
growing conditions requires a more liberal supply of those fixed 
substances in the soil, owing to vegetation having less time to 
search for them. It must also be borne in mind, that annuals 
recjuire a more liberal supply than perennials. In the climate of 
the United States the growth of all plants is more rapid than witb 
us. And, therefore, it is found, that sulphate of lime, phosphate 
of lime, and wood ashes, are more favourite manures for clover, 
grasses, and even cereals, than in Britain. The special effects of 
these substances in the United States may not be entirelv owing 
to climatic conditions ; but are no doubt partly to be asciibed to 
their influence, and ought certainly to be estimated in endeavour- 
ing to explain the phenomena of vegetable growth. 
In the manuring of flax and spring-sown cereals, therefore, it 
is of considerable importance to bear in mind, that phosphate of 
lime can sometimes be applied with advantage. Its special effect 
in promoting the growth of these crops will be all the more 
marked as the period of sowing is delayed. It has the effect of 
promoting early maturity", and in the case of the cereals a finer 
quality of grain is obtained. In cool and moist climates, par- 
ticularly, phosphoric manures impart a sounder though less 
* ' Transactions of the Xew York State Agricultural Society.' 
