4 PREFACE. 



important one to farmers and gardeners, as mucli of 

 their success must depend upon their acquaintance with 

 the various fertilizing agents, and the modes and circum- 

 stances of their employment. 



Judicious manuring alone will prevent farms from 

 gradually deteriorating, or wearing out to such an extent 

 as to be unj&t for cultivation. Deterioration <under an 

 improper mode of cropping and manuring, may pro- 

 ceed so slowly that it cannot be detected except by 

 keeping regular farm accounts, and comparing the pro- 

 duce of the same field at distant intervals, and under 

 the same crop. 



In the Report of the Massachusetts Commissioners, 

 in 1851, on the subject of an Agricultural School, the 

 following facts are stated : 



'Already the exhaustive process of perpetual crop- 

 ping has travelled over the once fertile lands of New 

 England, and in its desolating march is wending its way 

 over the fair fields of New York, Ohio, and on to the ^ar 

 West. Under the influence of this system of cultivation, 

 the crops of wheat in these States have receded from 

 an average of twenty-two bushels to fourteen bushels, or 

 less, per acre; and the same remark will apply to other 

 crops, in like ratio of reduction. 



''From this sad, but common error, Europe is just 

 recovering ; and, under the influence of her agricultural 

 schools, now scattered all over the continent, and of 

 scientific cultivation, her crop of wheat in many parts has 

 advanced from sixteen bushels to an average of over thirty 

 bushels per acre ; and a similar increase has taken place 

 in other crops. Wonders have also been achieved in 



