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The manures best fitted to the wheat crop are those which give it a 
vigorous but not too luxuriant growth in the autumn, to sustain it from, 
the severities of winter ; a rank and stout growth in the spring as pro¬ 
tection from the ravages of insects ; and which form a hard, clear, brit¬ 
tle straw, that will not be liable to rust and blight. 
Lime is a good manure for wet and for hard soils ; for light porous 
soils it almost always hurtful. Its effects on proper soils is to increase 
the quantity of the grain, to give it a thinner and clearer bran, and to 
increase its proportion to the same amount of straw and chaff. The 
quantity of gluten is greater in wheat grown on limed soil than that 
grown on others. Districts underlain with lime are almost universally 
good wheat districts. Its effects are more marked on spring than on 
winter wheat. It is not a durable manure and soon loses its peculiar 
fructifying power. It should be frequently repeated, and applied only to 
the surface, where the atmosphere can act readily upon it. 
The use of alkalies upon soil is simply to neutralize the superabundant 
acids, generated by decomposition and other influences, which obstruct 
the further decay of vegetable matter, and are unfavorable to the 
healthy growth of the plant. 
All straw, stalks, leaves and chaff are excellent manures for wheat. It 
is the growth of the straw which most rapidly exhausts soil, extracting 
from it the silicates, the lime, the phosphoric acid, and the alumina, 
which are its principal elements, as well as its other constituents, which 
are not indeed great in quantity, but which do not exist in great quan¬ 
tities in the soil. To again apply the straw, whether dry, or in any of 
its various stages of decomposition, is to restore to the soil the same ele¬ 
ments which the previous crop extracted from it. 
Guano is the name given to the extensive deposits of dung, chiefly that 
of sea-birds, upon the rocky promontories and islands of South America. 
The climate is dry and the process of decomposition goes on exceedingly 
slow—so slow that beds have been formed from twelve to sixty feet in 
thickness. At the proper stage of decomposition, it is the most active 
and powerful manure known. The usual application is about 200 lbs., as 
a top-dressing, to the acre. Its quality is very variable, as it is exposed 
to the atmosphere, by which its more volatile constituents escape, or as 
