PUBLISHERS' PREFACE. 



The improvement of the soil by drainage and irriga- 

 tion, and by liming — the maintenance of its fertility by 

 the operation of our tillage implements — its exhaustion 

 by cropping, and its restoration by manuring — are the 

 proper subjects of these pages. The resources of the 

 farmer, in the economy of home manures and in the use 

 of manufactured and imported fertilizers, are considered 

 in detail. 



Fertility of course depends not only on the soil but on 

 the climate. And it is on the fitness of the circumstances 

 in both these particulars that the luxuriance and pros- 

 perity of plant growth rest. The principles on which 

 fertility is dependent may be the same in all climates. 

 The capability of obtaining from soil and air the building 

 material of the growing plant is everyw^here its limit, 

 but it is the climate alone which determines the yegeta- 

 tion in which the fertility is exhibited. 



Messrs. J. B. Lawes, J. C. Morton, John Scott, and 

 George Thurber, so eminent in their fields of labor, are 

 the writers of these valuable pages. 



May, 1883. 



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