ROTATION 



MR. THOMAS BLACKIE's SCHEME OK RO- 

 TATION UPON A FARM OF ONE HUN- 

 DRED ACRES, AS PROPOSED TO THE 

 FRENCH GOVERNMENT. 



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briefly stated that leguminous crops 

 are regarded as lime crops ; the corn ^ 

 crops as potash and bone-earth crops, 

 and most roots and green crops as 

 potash crops ; and that these sliould 

 severally succeed each other in a 

 well-tilled and prepared soil. 



' To l>e ploughed ap after seven years, aad fotloweii 

 by wheat. J 



I. L L 



OF CROPS. 



Boussingault, who has taken an- 

 other view of rotations, and main- 

 tains that they should be so directed 

 as to economize the nitrogen or am- 

 monia of manures, has entered into 

 an extensive series of researches to 

 determine the best rotations. He 

 analyzed his crops and manures, and 

 calculated the amount of each com- 

 ponent they carried from the field. 

 As the rotations are good, we have 

 no hesitation in presenting them, 

 with his results. 



" The measure of dung in use at 

 Bcchelbronn is the wagon drawn by 

 four horses. After repeated weigh- 

 ings, it was found that this measure 

 contains nearly 1 ton. 15 cwt., 2 qrs., 

 23 lbs. of moist material, or 7 cwt., 



1 qr., 15 lbs., if that be computed dry. 

 The first course of the rotation re- 

 ceives 27 loads of this manure, weigh- 

 ing about 48 tons, 14 qrs., 5 lbs., 

 equivalent to 9 tons, 19 cwt., qr., 



2 lbs. of dry manure per hectare, or 

 20 tons per acre. 



" The preceding analyses show 

 that this charge of manure, which is 

 to fertilize the soil during the course 

 of the rotation (five years), contains, 



Carbon 8,027 lbs. 



Hydrogen 925 



Oxygen 5,767 



Azote 447 



Salts and earth ....... 7,188 



22,355 



" Such are the principles which, 

 together, form the organic matter 

 that is to be consumed, and, in a ma- 

 jor part, assimilated by the crops 

 grown. I say partly, because I do 

 not believe that the whole organic 

 matter necessarily enters into the 

 constitution of the plants which 

 spring up during the rotation ; no 

 doubt a considerable portion of the 

 manure is lost through spontaneous 

 decomposition, or is carried away by 

 the rain ; and another portion may 

 remain a long time dormant in the 

 soil, to act as a fertilizer at a more 

 or less distant period ; just as, in the 

 present rotation, the manure former- 

 ly introduced co-operates with that 

 recently added. One thing is cer- 

 tain, viz , that the proportion of ma- 

 nure indicated is essential for aver- 



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