IGO STATE BOARD OF AGRICULTURE. 



" lAUM FEllTILIZKRS." 



In coiisitleriiig tlie sources from whence the elements of plant growtli come, 

 and tlie manner of supplying them, we will first consider tlie natural means, 

 afterwards, the artificial. 



The atmosphere that encircles the earth contains some of the ingredients 

 essential to plant growth, oxygen, nitrogen, and carbonic acid. It has been 

 estimated that there are seven tons' weight of this latter gas over every acre 

 of the earth's surface, and that over one-lialf of the carbon composing the 

 •blades of grass, the stalks of grain, and trunks of trees, comes from that 

 source. Its presence in the atmosphere is ]H'oduced by such agencies as fires, 

 breathing of animals, and putrefaction of animal and vegetable matter. The 

 remainder of the carbon, or less than one-half, is introduced from the soil, 

 the roots acting as the conducting medium. But to form the stalk and leaves, 

 the starch and sugar, tliere is required a union of carbon with oxygen and 

 hydrogen. These two elements are derived largely, in fact almost wholly, from 

 water. This liquid, as it with other substances is absorbed, becomes decom- 

 posed, euters into new combinations forming component parts. While carbon, 

 oxygen, and hydrogen are the principal elements employed in the structure of 

 plants, and nitrogen is not essential to their growth, it nevertheless enters into 

 their composition and is indispensable to the development of fruits, grains, 

 and seeds. Where does it come from ? From its abundance in the atmos- 

 phere, constituting about four-fifths, it would be a natural conclusion that it 

 is taken from the air. But unlike carbon it is but sligtly derived from that 

 source, and is introduced from the soil. IIow ? The chemist can find do 

 nitrogen in the soil, but does find substances that contain it. The most abun- 

 dant of these is carbonate of ammonia. This is taken into the vegetable lab- 

 oratory, analyzed, and contributes to growth. 



Aside from the four elements entering into a composition of the vegetable 

 kingdom and constituting organic food, there are other substances found; 

 such as potash, phosphorus, silica, lime, etc., these are known as inorganic 

 food, and are not needed for growth, but are absolutely essential to a perfect 

 development. The organic part of plants, composed of gases, is a volatile sub- 

 stance and upon separation from the inorganic, flies into the air. Inorganic 

 portions may be seen in the remains of vegetable matter after decay has fin- 

 ished its work, and in ashes, after fire. It is estimated that ninety-eight-hun- 

 dredths of the stock of our grains, and all woody substances is organic matter, 

 and the remaining two-hundredths inorganic. In view of this fact it will need 

 no after argument to show the folly of a practice, prevalent with some, of 

 burning straw. While such are themselves losing the great bulk of its sub- 

 stance, they are, though unconsciously, public benefactors. 



Prof. Liebig separates all cultivated plants into three classes, viz. : jDotash, 

 lime, and silica. Potash plants are those in which potash and soda enter 

 largely as bases. The beet, turnip, etc., are of this class. Lime plants are 

 those in which lime and magnesia are the principal ingredients, — among such 

 may be placed tobacco and clover. Silica plants embrace those in which silica 

 is the prominent part in the ashes, such as wheat, rye, oats, and barley. So 

 then, the study of the farmer is too plant his grain and sow seed in soil that 

 contains suitable elements, and if destitute or deficient of such, it is his busi- 

 ness to supply them. Some of these methods we will consider under the 

 head of 



