SO GARDENING FOE THE SOUTH. 



CHAPTER V. 



ROTATION OF CROPS. 



The same crops cannot be grown from year to year 

 upon the same soil without decreasing its productiveness. 

 All plants more or less. exhaust the soil, but not in the 

 same degree, nor in the same manner; hence, as different 

 plants appropriate different substances, the rotation of 

 crops has considerable influence in retaining the fertility 

 of a soil. If the same kind of plant is continued upon 

 the same soil, only a portion of the constituents of the 

 manure applied is used; while by a judicious rotation 

 everything, in the soil or in the manure, suitable for vege- 

 table food, is taken up and appropriated by the crop. 

 However plentiful manure may be, a succession of ex- 

 hausting crops should not be grown upon the same bed, 

 not only because abundance is no excuse for want of 

 economy, but because manure freshly applied is not so 

 immediately beneficial as those remains of organized 

 matter which by long continuance in the soil have become 1 

 impalpably divided and diffused through its texture, and 

 of which each succeeding crop consumes a portion. 



Some crops are so favorable to weeds, that if continued 

 long upon the same bed, the labor of cultivating them is 

 much increased, while if raised but once in a place and 

 followed b}^ a cleaning crop, the weeds are easily kept 

 under. Besides, many crops planted continually in the 

 same soil are more liable to be attacked by the insects and 

 parasites which are the peculiar enemies of those plants. 



Many insects injurious to plants deposit their eggs in 

 the soil which produced the plants they have infested, 

 ready to commit their depredations upon the succeeding 



