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influences. Organic matter often reposes in the soil, in what has been 
termed an innate state, undergoing decay but slowly, and in but a small 
degree discharging the functions of fertilization. Frequent, or prolonged 
exposure to the air, the sun and rain, will render them active agencies 
in vegetation. The rains bring down in their periodical visitation sup¬ 
plies of all the native substances as they exhale from the sea—common 
salt, gypsum, salts of lime, of magnesia, and of potash, in greater or 
less quantities, with nitrate of ammonia generated or present in the at¬ 
mosphere, and foreign substances blown about by the wind and lodged 
in the air in minute solid particles, or as liquids and gases. If the soil 
has become deficient in these elements, they will accumulate on it and in 
it during its year of rest, and yield to the succeeding crop a rich and 
luxurious nourishment. 
The process of seeding, or green fallowing, is of similar benefit to the 
soil. The green crop demands a comparatively small supply from the 
inorganic substances that afford the material and peculiar nourishment 
to grain. The additional vegetable matter and manure which they intro¬ 
duce into the soil, by being plowed under, adds greatly to its fertility, and 
compensates for the loss of those benefits which a naked fallow would 
have produced. 
Drainage is of great efficacy on hard, heavy, clayey soils, by leaving 
them open and porous. It is valuable on all low, wet soils, by carrying 
off the stagnant water and giving passage to the excess that falls in rain. 
It arrests the ascent of water from beneath, whether by the force of 
capillary attraction, or from the action of springs, preserving the surface 
from an improper moisture, and the subsoil from lingering and noxious 
substances lodged in it that impair the wholesome growth of the plant. 
It allows the water which falls from above to make its way through the 
soil instead of washing and bearing away the surface. It opens the pores, 
so that fresh air can get to the roots of the plant. Wet lands are always 
cold, from the influence of evaporation. Drainage removes the source 
of too much evaporation, rendering the soil warmer. It makes the soil 
drier, sweeter, looser, and more friable. It greatly increases the fertil¬ 
izing properties of many artificial manures, such as wood ashes, bone, 
lime and nitrate of soda, which are greatly injured by sour and stagnant 
water resting in the pores of the soil. 
