BUYING PLANT FOOD FOR THE SOIL 23! 



manure for lands. When prepared for commercial use, 

 it contains fifteen and one-half to sixteen per cent, of 

 nitrogen, or 320 pounds to the ton. The remaining 1,680 

 pounds of the ton are the elements sodium and oxygen, 

 to which the nitrogen is united, and these form the nitrate 

 of soda. In addition to these, forty to sixty pounds of 

 impurities mostly common salt are present in each 

 ton of the commercial product. 



Nitrate of soda dissolves in water with great ease, and 

 readily distributes itself in the soil. It is in this form 

 that plants like most to use nitrogen, and it is in this 

 form they take it up in greatest abundance: in no other 

 does nitrogen act more quickly or show its effect more 

 quickly when applied to the soil. So in two or three days 

 after an application of the fertilizer is made, its effect is 

 seen on growing plants. They show an increase in vigor, 

 a deeper green color is seen, and greater activity in 

 growth is apparent at once. 



In this connection it might be worth your while to 

 recall to mind this fact: nitrogen, in nearly every case, 

 enters plants as a nitrate. Sulphate of ammonia, for in- 

 stance, when used as a fertilizer, sometimes is acted upon 

 by micro-organisms which change the ammonia form to 

 the nitrate form. Of course, there is an objection when 

 any large quantity of nitrates are present in the soil : it is 

 soluble, and soil water and drainage waters gather it up 

 and carry it away out of reach of plants, out into the 

 sea, perhaps. A great quantity of nitrogen is lost in this 

 way each year. 



Dried blood contains from eight to twelve per cent, 

 of nitrogen and from seven to fourteen per cent, of phos- 

 phoric acid, and is the richest substance coming from ani- 

 mal products. 



When live stock is slaughtered, the blood is collected in 



