ROTATION OP CROPS. 14T 



maturely old, have gone to decay, fallen to the earth, and their 

 places supplied by the pine. A ripe forest of either kind re- 

 moved by clearing, and the soil left to nature's working, will in 

 due time be replaced by one different from that which first occu- 

 pied the ground. This fact is not the result of chance, neither 

 is it because the soil is worn out and destitute of plant-food ; 

 for the second growth is strong and rapid, indicating that it is 

 well supplied with nourishment, Ijut it points to our second 

 great law for rotation. Plants of different kinds and species do 

 not require for their perfect development the same kind or 

 quantity of food material. We have potash-plants, plants 

 which, though they partake sparingly of nearly all the other 

 mineral and of the organic elements in the soil, will not grow 

 and mature satisfactorily unless they are well supplied with pot- 

 ash in a soluble form. So, too, nature has provided tlie lime- 

 plant, the soda-plant, plants that delight in phosphoric and 

 sulphuric acids and their salts, and plants that do and that do 

 not require the stimulating, forcing influence of abundant nitro- 

 gen. Therefore, it is that on a soil which is new or has a large 

 accumulation of plant-food, we may grow a potash-plant year 

 after year until the leading element of its nature becomes defi- 

 cient, and its yield depreciates, and then follow it with a lime- 

 plant, which may flourish as if the soil had never been cropped. 

 That, with a plant requiring some other as a leading element, 

 and so on, the entire round of plant-food, and the whole round 

 give us paying crops. Or we take any plant we choose at 

 regular periods, and rely on the processes of nature that are 

 perpetually at work in the soil, to develop a sufficient supply of 

 its predominating element during the interval of its absence, 

 to give it a luxuriant growth when it shall be returned to the 

 soil. 



But again, leaving out of sight all the pros and cons of the 

 disputants over the excrementitious theory ; the theory, that 

 plants can make no choice in their food, but must, and do, take 

 up in their sap everything in the soil that is soluble, and retain- 

 ing only such in their growth as is agreeable, but returning to 

 it as excrements the remainder, and after a time poisoning it, 

 or rendering it unfit to nourish that class of plant — though 

 after decomposition some other plant would thrive on the dis- 

 carded material — it is certain that observing, practical men, 



