SUCCESSION OF CROPS IN ROTATION. 227 



The succession of crops in rotation is always made 

 dependent upon the cereals ; the preceding crops are 

 selected of such a kind that their cultivation will not 

 injure, but rather improve, the succeeding corn-crop. 

 The selection of the particular kind, however, is always 

 governed by the condition of the soil. 



In a field abounding in stalk and leaf constituents, 

 it is often found useful to have wheat preceded by 

 tobacco or rape, rye by turnips or potatoes, since these 

 plants by drawing from the soil a large amount of leaf 

 and stalk constituents serve to restore a more suitable 

 proportion between the straw and corn constituents for 

 the future cereal crop, and at the same time to diminish, 

 in the arable soil, those conditions which favour the 

 growth of weeds. 



The preceding observations relative to the produce 

 given by the Saxon fields, both in the unmanured and 

 manured state, afford, in my opinion, a perfect insight 

 into the nature and results of cultivation by the system 

 of farm-yard manuring. In the condition of these fields 

 in their several stages, we may see reflected the history 

 of agriculture. 



In the first period, or on a virgin soil, corn-crop is 

 made to succeed corn-crop, and when the produce be- 



fins to fail, the culture is simply transferred to a fresh 

 eld. The increasing requirements of the growing 

 population, however, gradually put a check upon this 

 plan, and compel a steady cultivation of the same sur- 

 face ; a system of alternate fallowing is now resorted 

 to, and efforts are made to restore the lost fertility of 

 the soil, by manuring with the produce of the natural 

 meadows. After a time, this expedient begins to fail, 

 and leads to the cultivation of fodder-plants, the sub- 

 soil being thus turned to account as an artificial mead- 

 ow. The cultivation of fodder-plants proceeds, at first, 

 without interruption ; after a time, longer and longer 

 intervals are interposed between the clover and turnip 

 crops ; finally, the cultivation of fodder-plants comes to 

 an end, and with it the system of cultivation by farm- 

 yard manuring. The ultimate result is the absolute 



