HOW CROPS FEED. 



INTRODUCTION. 



In his treatise entitled " How Crops Grow," the author 

 has described in detail the Chemical Composition of Agri- 

 cultural Plants, and has stated what substances are indis- 

 pensable to their growth. In the same book is given an 

 account of the apparatus and processes by which the plant 

 takes up its food. The sources of the food of crops are, 

 however, noticed there in but the briefest manner. The 

 present work is exclusively occupied with the important 

 and extended subject of Vegetable Nutrition, and is thua 

 the complement of the first-mentioned treatise. "Whatever 

 infoimation may be needed as preliminary to an under, 

 standing of this book, the reader may find hi "How Crops 

 Grow." * 



That crops grow by g;ithering and assimilating food ia 

 a conception with which all are familiar, but it is only by 

 following the subject into its details that we cm gain hints 

 that shall apply usefully in Agricultural Practice. 



* It has been at least the author's aim to make the first of this series of book* 

 prepare tlie way for tlie second, as both the fir!«t and the second are written tu 

 make possible an iiitelli<;ible aceonnt of tlie mode of action of Tillage and of 

 Fertilizers, which will be the subject of a Mrd work. 



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