THE SOIL 51 



TABLE VIII. Fertility Lost by Burning Straw. 



Thus, if w.e assume that the fertility elements lost by 

 burning the straw could be applied to the production of 

 wheat, we find that in each ton the nitrogen would be 

 sufficient for 7.1 bushels of wheat, the phosphorus for 

 6.7 bushels, and the potassium for 69.2 bushels. These 

 losses, together with the loss of other benefits 

 of organic matter, are the results of burning the straw. 

 Where straw or manure is spread on the land and then 

 burned over only the nitrogen and organic matter are 

 lost. Phosphorus, potassium and other mineral elements 

 are not destroyed by burning. The ashes are valuable as 

 fertilizer if spread evenly over the land. 



Green manuring is the practice of growing crops for 

 the express purpose of plowing them under to improve 

 the soil. In the older countries legumes are most com- 

 monly used, though buckwheat and rye, the latter used 

 as a cover crop, are widely used. Since this country will 

 never be thickly populated with stock and since the 

 depletion of organic matter in the soils is already be- 

 coming apparent, green manuring must, of necessity, 

 come into common practice, if the organic matter in our 

 soils is to be maintained. 



Pasturing, from the standpoint of soil fertility, is the 

 most economical method of returning manure to the land. 

 The expense of hauling and spreading is saved, and the 

 losses by fermentation (fire-fanging) as occur in the 

 manure pile in the farmyard, are avoided, 



