THE SOIL 53 



constituents being easily possible during three or four 

 months, m part from fermentation, which may occur 

 even under cover, and in part from leaching where man- 

 ure is exposed to the weather or where little or no 

 absorbent bedding is used." 



Concerning manure the North Dakota Experiment 

 Station* finds that, "approximately one-half of the 

 fertilizing value of manure is lost in rotting, so that it 

 probably requires 2 tons of fresh manure to make 1 ton 

 of rotted manure. Considering the cost of extra hand- 

 ling of rotted manure it would be more profitable to 

 haul the manure directly from the barn to the field. It 

 can be applied to best advantage to pasture in the 

 rotation or plowed under for corn". 



38. Functions of Organic Matter. — Organic matter re- 

 turned to the soil functions in several ways : 



1. By improving the physical tilth by increasing the 

 humus content as already discussed (i.e. increases the 

 water-holding capacity; increases the pore space, hence 

 the "warmth" and "earliness" ; renders clays easier to 

 work; gives better adhesiveness to sands, etc.). 



2. By supplying the essential elements it contains. 



3. By assisting in dissolving the insoluble plant food 

 elements through the action of the acids produced in the 

 decay of the organic matter. 



The first two items have already been discussed, the 

 third will be taken up under the action of bacteria in the 

 soil. 



39. Losses of Organic Matter in the Soil.— That the 

 present system of farming which makes no adequate 

 provision for the return of organic matter is rapidly de- 



♦Doneghuj, North Dakota Agricultural Experimental Station 

 Bulletin 126. 



