Il8 PLANT DISEASE 



CHAPTER VII 



AGRICULTURE 

 HUMUS 



Elements of Agriculture, prepared under author- 

 ity of the Royal Agricultural Society of Eng- 

 land, by W. Fream, LL.D., pp. 15, 16 



" Nevertheless, humus is of great value be- 

 cause the final products of its decomposition, 

 chiefly carbonic acid, ammonia, and water, are 

 capable of administering to the food require- 

 ments of growing plants. . . . The quantity of 

 humus usually present in cultivated soils ranges 

 from 2 to 9 per cent., and within these limits 

 the soil will be the richer or more fertile, 

 the more humus it contains. . . A soil rich in 

 humus is better able to withstand drought." 



It is noticeable that in the above passage 

 no reference is made to the quality of the 

 humus ; although Storer does speak of the 

 better kinds of humus, yet it may be a chloro- 



