Nitrogen 

 Abundant 

 but not 

 Available 



ashes, which the chemists call "ash," or worganic matter. Gener- 

 ally speaking, therefore, we find that 100 lbs. of green crops con- 

 sist of: 



Water 85 to 90 lbs. 



Organic Matter . . . 10 to 15 lbs. 



Which consists of: 

 Carbon 

 Hydrogen 

 Oxygen 

 Nitrogen 



Inorganic Matter (Ashes) . 2 to 3 lbs. 



Which consists of: 

 Phosphorus 

 Sulphur 

 Potassium 

 Calcium 

 Magnesium 

 Iron 

 Sodium 

 Chlorin 

 Silicon (Sand) 



It would appear from the foregoing table that water is the 

 largest factor in growing all crops, but unfortunately, in general 

 farm practice, the farmer is dependent upon the rains to supply 

 it. It is a factor beyond his control except by irrigation. It 

 is known that thorough tillage will conserve moisture in the 

 soil and is absolutely essential in dry seasons, hence constant 

 and thorough cultivation is the basis of successful "dry farming" 

 in arid regions where water is not obtainable. 



The organic matter we observe is composed of carbon, hydro- 

 gen, oxygen and nitrogen. Now the first three are supplied in 

 abundant quantities through the air and water by the aid of sun- 

 shine, which in nature's laboratory converts these elements into 

 the structure of the plant, which we know as stalk, leaf or straw; 

 also as starch in the potato and grain, or sugar in the fruit. It 

 is a curious fact of nature, however, that while nitrogen is the 

 largest constituent of air, being four-fifths of its volume (equal to 

 35,000 tons over every acre of soil), yet it is not directly available to 

 general farm crops. It is not positively known that any crop 

 can extract nitrogen from the air except the clover family, 

 which, through nodules on the roots, absorbs nitrogen from the 

 air in the soil. 



