SCIENTIFIC AGRICULTURE. 18 



Boussinganlt states that ho saw in South America, fields on 

 which good crops of wheat were said to have been produced 

 annually for more than two centuries ; and also that potatoes 

 arc cultivated continually on the same soil. It is stated also 

 by Colman, that onions yield more and more abundantly the 

 oftener they are grown on the same field. These statements 

 either contain some hidden fallacy, or they prove that the fields 

 in question contained an inexhaustible amount of the elements 

 necessary to the plants produced ; for they do not, nor were 

 they designed to prove, that rotation is unnecessary. 



It is unquestionable that a perfect system of agriculture, 

 and the maximum production of all crops, requires a system 

 of alternation, regulated according to circumstances, and in 

 accordance with the principles of Chemistry. A valuable end 

 to be obtained by rotation is the destruction of certain weeds 

 and the insects which inhabit them. 



The following table shows a system of rotation which is 

 practiced in Pennsylvania. 



First year Grass or clover. 



Second " Pasture. 



Third " Indian corn. 



Fourth " Oats or barley (manured.) 



Fifth Wheat. 



Sixth " Grass (plastered.) 



The tables below are from Colman, and show some courses 

 of rotation practiced in England. 

 First year Turnips (manured.) 

 Second " Barley. 

 Third " Clover. 

 Fourth Wheat. 



0)i a Clay Soil. 



First year Swedes turnips and Mangel Wurtzel. 

 Second " Wheat and beans, (i. e., part of land in each.) 



