120 PLAHT LIFE OK TSE FARM. 



average, to four to five tons with farm-yard manure, 

 and to six to seven tons with mixed mineral and am- 

 monia. The tendency to disease, however, increases with 

 the higher manuring, in larger proportion than does the 

 produce. 



The data of science on the effect of manures must, 

 however, only be taken as indications by the practical 

 farmer, who must be guided by financial considerations 

 and local conditions, in determining what it is best for 

 him to do under particular circumstances at any given 

 time. 



An interesting circumstance may here be mentioned, 

 viz : that many of our cultivated plants, such as cab- 

 bages and mangold wurzel, have sprung from wild plants 

 growing by the sea, and are hence especially benefited by 

 the use of salt as a manure. Onions, the growth of 

 which is also favored by salt, probably originated from a 

 wild stock growing in salt desert regions. 



Fallow, The good effects of this may be judged from 

 the results of some Eothamsted experiments, in which 

 the produce of wheat is recorded, after bare fallow, com- 

 pared with that of wheat grown continuously on the 

 same soil, without the intervention of fallow, and equally 

 without manure. Under such circumstances, the aver- 

 age produce for twenty -five years after fallow has been 

 eighteen bushels per acre, as contrasted with an average 

 of twelve bushels where the wheat has been grown con- 

 tinuously. The weight per bushel was the same in both 

 cases. The average quantity of straw after fallow was 

 one thousand seven hundred and eighty-six pounds, as 

 contrasted with one thousand two hundred and twenty- 

 one pounds, where the crop was grown continuously. 



Rotation. The practice of rotation of crops is amply 

 borne out by what occurs in nature and by chemical ex- 



