ROTATION OF CROPS. 271 



the latter may be ; unless they are snch as receive an annual 

 or occasional dressing from the overflow of enriching floods, 

 or are artificially irrigated with such water as holds the 

 necessary fertilizing matters in solution ; and such are not 

 exceptions, but receive their manure in another form, 

 unaided by the hand of the husbandman. Neither are old 

 meadows (mowing lands filled with the natural or unculti- 

 vated grasses, or whatever of useful forage they choose to 

 bear), exceptions to this rule ; although they may part with 

 a portion of their annual crop in the hay, which is removed, 

 and which is not returned as manure, and by a partial rest 

 or pasturage, appear to sustain their original fertility. But 

 if the true character of the various plants which they pro- 

 duce, were accurately observed, and all of which are indis- 

 criminately embraced under the general head of grass or 

 hay, it would be found that the plants gradually change 

 from year to year ; and while some predominate in one 

 season, others take their place the year succeeding, and 

 these again are supplanted by others in an unceasing round 

 of natural rotation. 



Another illustration of rotation may be observed in the 

 succession of forest trees that shoot up on the same soil, to 

 supply the places of such of their predecessors as have de- 

 cayed or been cut down. Thus, the pine and other of the 

 coniferse, are frequently found to usurp the place of the oak, 

 chestnut, and other deciduous trees. This sometimes occurs 

 only partially, but in repeated instances which have come 

 within my notice, forests have been observed to pass entirely 

 from one order of the vegetable creation to its remote oppo- 

 site, the seeds or germs of which (the product of an ancient 

 rotation), had been lying dormant for centuries, perhaps, 

 waiting a favorable condition of circumstances and soil to 

 spring into life. 



Many choice secondary bottom lands, and others munifi- 

 cently supplied by nature with all the materials of fertility, 

 have, by a long succession of crops, been reduced to a con- 

 dition of comparative sterility. Yet it will have been found 

 in the progress of this exhaustion, that after the soil ceased 

 to give^an adequate return of one crop, as of wheat, corn, 

 or tobacco, it would still yield largely of some other genus 

 which was adapted to it. These lands, when thus reduced, 

 and turned out to commons for a few years, will again give 

 crops much larger than those which closed their former 

 bearing career, proving that nature has been silently at 



