Vou XIV. 



ROCHESTER, N. Y, FEBRUARY, 1853, 



No. II. 



THE FARM AS A MANUFACTORY. 



NUMBER TWO. 



The benefits derived from a judicious rotation of crops are now all but universally 

 admitted. The reasons assigned for the necessity or advantage of rotation are very 

 various. A very plausible theory advocated by De Candolle, attributed the necessity 

 of rotation to a supposed excretion from the rootlets of plants. These vegetable excre- 

 ments were said to he very injurious and even poisonous to the same kind of plant that 

 excreted them, but were of great fertilizing value to other plants of a different character. 

 Many experiments have been made to test the truth of this beautiful theory, the results 

 of which are adverse, and force us to believe that though some plants may excrete mat- 

 ter that is not suitable food for them, our commonly cultivated plants, as wheat, maize, 

 potatoes, maidow grasses, &c., do not thus excrete injurious matter ; but that if the land 

 be kept clean and the required fertilizers or constituents are supplied, these plants can 

 be grown amiually on the same soil as long as desired. 



Another theory, advocated by many of the ablest chemists of the age, refers the 

 advantage of rotation to the variable amount of inorganic constituents required by the 

 different crops forming the rotation. The generally adopted system of rotation in tke 

 best farmed districts of England, and which an experience of fifty years has sanctioned 

 as being judicious and beneficial, is as follows : First year — wheat after clover. Second 

 year — turnip?-, partly eaten on the land by sheep. Third year — barley or wheat seeded 

 with red and other kinds of clover. Fourth year — clover, mown for hay or eaten on 

 the land, followed by wheat in the fail at one plowing ; and so on as before. The advo- 

 cates of this theory point to this well established system of rotation as practical evidence 

 in support of their chemical deduction, and reason thus : The ash of wheat contains 

 50 per cent of phosphoric acid, the ash of turnips only 11 per cent. We can not gi-ow 

 wheat after wheat, because the land is exhausted of available phosphoric acid ; but 

 turnips, requiring only a small quantity of phosphoric acid, will do well after wheat, as 

 experience proves. 



In answer to this, we say that experiments show that an application of an ammoni- 

 acal salt containing not a particle of phosphoric acid, will cause the wheat plant to grow 

 luxuriantly and yield successive annual crops of thirty bushels per acre, while on the 

 same soil turnips will not grow larger than radishes, though dressed with every kind of 

 manure in which phosporic acid is not a constituent ; but an application of available 

 phosphoric acid produces annually good crops of turnips. These experiments, extending* 

 over nine successive annual crops, together with the fact that phosphoric acid is not 

 used in general practice as a manure for wheat, while it is applied to an enormous extent 

 and with the most beneficial results as a direct manure for turnips, are sufficient to dis- 



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