344 STATE BOARD OF AGRICULTURE. 



THE NITROGEN TROBLBM IS ACUTE IN SOME SECTIONS. 



Nitrogen is necessary for plant growth. The maintenance of ample 

 amounts of active vegetable matter or humus in the soil to supply nitro- 

 gen to crops and to keep the soil in good condition constitutes our 

 greatest soil problem. Therefore the nitrogen and humus problem 

 needs special consideration. 



Nitrogen is found in all plants, soil organic matter or humus as well 

 as in several commercial forms. When present in or added to the soil in 

 suitable compounds it results in an intensity of the green coloring matter, 

 and increases the root, stem and leaf development or the vegetative 

 portions of the common plants. On the other hand it is well-known 

 that the presence of an excess of available nitrogen may prevent proper 

 seed formation and cause loding of grains and grasses, especially if the 

 phosphorus and potassium are somewhat deficient. The amount at the 

 disposal of the crop affects greatly its quality in as much as large 

 amounts result in the formation of soft tissue. Therefore, one may 

 regulate somewhat the quality of such crops as cabbage, celery, lettuce, 

 asparagus and others by controlling the nitrogen relationships. It is 

 well to mention that excessive amounts prolong the growing period or 

 delay maturity. 



Nitrogen starvation is indicated by yellowish or pale-green colored 

 leaves, lack of thriftiness or a general stunted appearance. It should 

 be recalled that other soil conditions may result in similar symptoms. 



Sources of Nitrogen. There are four chief sources of nitrogen for crops, 

 namely from vegetable matter or humus, from bacteria in legumes, from 

 bacteria and other forms in the soil and from commercial fertilizers. 

 The chief source for most crops is the soil vegetable matter, commonly 

 spoken of as humus. 



Nitrogen from vegetable tnattcr is imjwrtant. Before this nitrogen is 

 made use of or taken from the soil by the crops the process of decay 

 or rotting and nitrification or the formation of nitrates must take place. 

 Decay may be and usually is brought about by several kinds of organisms 

 or germs which infest the soil. These processes or the making available 

 the nitrogen of the humus may be slow under some conditions and rapid 

 under others. 



When the soil is cool or the temperature is low and it is wet, decay 

 and consequently the rendering of the nitrogen available for crops is 

 very slow. On the other hand when the soil is warm and moist, but not 

 soaked with water, these processes are much more rapid. If lime is 

 deficient in the soil its addition results in hastening decay. It has also 

 been shown that phosphorus acts similarly and it is probable that the 

 splendid effects of acid phosphate, late in the autumn and early in the 

 spring, are due in part to this action. 



The kind of material that is added to or is present in the soil governs 

 the rate of formation of available nitrogen. It is well recognized that 

 clovers, alfalfa, beans, peas and vetch decay more rapidly in the soil 

 than do straws of the cereals. The breaking down of the latter may 

 proceed very slowly if lime is deficient in the soil. 



The rate of decay and consequently the formation of nitrates in the 

 soil is most rapid near the surface. This may be illustrated by the 

 <«onditions of fence posts that have been in the soil a number of years. 



