118 - PLANT LIFE ON THE FARM. 
cofiditions than others. Thus spring wheat, barley, or 
oats, may be made in a degree to supply the deficiencies 
of the autumn sown wheat, and tares, beans, peas, 
carrots, etc., etc., employed to compensate for the failure 
of other crops. 
Manures.—By the judicious use of suitable manures 
at the right time, the farmer is also enabled in some de- 
gree to provide for and counteract the effects of unpro- 
pitious seasons. Farm-yard manure, for instance, not 
only increases the quantity of grain and of straw, but 
greatly improves the quality of the grain, as measured in 
pounds per bushel ; and the same holds good of a mixed 
mineral and nitrogenous manure. 
The time when nitrogenous manures can be most 
beneficially applied is a matter of great consequence, 
Messrs. Lawes and Gilbert having proved that the 
nitrogen carried off the land in the drainage water, is 
much greater when the manure is applied in the autumn 
than when used in spring. Another illustration of the 
use of manures of an opposite character to that just 
cited, is afforded by the use of common salt (sodium 
chloride) to check rank growth with its tendency to pro- 
_ duce straw rather than grain. 
The varying eects of season, according to the nature 
of the manure employed, suggest also that a variety of 
manures should be used. In the Rothamsted experi- 
ments, it has been shown that the seasons which proved 
most propitious to the unmanured crops, and to those to 
which only mineral manures were applied, were not 
equally so for the crops to which nitrogenous manures 
were applied; hence, says Sir J. B. Lawes, *‘ the best season 
for land in low condition is not the best for land in high 
condition.” 
The varying effects of manure may be illustrated by a 
few figures taken from the Rothamsted ‘‘ memoranda” ; 
