COMPOSITION OF ROOTS AND STUBBLE. 207 



That this practice is adapted for the improvement of all 

 soils. 



It is a common practice among farmers to plow under a 

 sod of grass grown for the purpose, as manure. The usual 

 seeding of clover and timothy is thus intended fdr breaking 

 up at the end of the second year for the corn crop. It will 

 be interesting to know what amount of fertilizing matter is 

 thus contributed to the soil. The following table affords 

 this information. 



AMOUNTS AND COMPOSITION OF ROOTS AND STUBBLE 

 OF THE FOLLOWING CROPS. 



Clover 6f>SO 



Wheat 2240 



Rye 3400 



Oats 2200 



Timothy 1982 



Peas 2400 



Mixed grasses and clover 5000 



These figures will probably be found below the average 

 of what are called good crops. For it has been found that 

 the living roots and stubble of a four year old sod has been 

 equal in weight to one-sixth more than the weight of the 

 last years crop. Also, that in an old pasture or meadow 

 which has been laid down for many years, the actual vege- 

 table matter contributed to the soil has been ascertained to 

 be equal to four times the weight of the last years vegeta- 

 tion above the surface. The author has found by careful 

 measurement and weight, that the amount of vegetable mat- 

 ter contributed to the soil per acre by turning under an old 

 growth of quack grass, (Triticum repens), was equivalent 

 in weight and bulk to 80 tons of ordinary stable manure. 



When land is in grass for a number of years there is a 

 very large accumulation of organic matter in the soil from 

 these sources, viz: the contributions from the atmosphere of 

 combined carbon and nitrogen; from the dead and decay- 

 ing roots and stems of the grass; and from the mineral parts 



