ALTERNATION OF CROPS. 155 



Yet it is better to regulate our practice by general laws, 

 than by casual exceptions. In the cases noted as excep- 

 tions, there is probably so great an accumulation of the 

 specific food of the particular crop, that it has not been 

 exhausted^ though it evidently must have been diminished. 

 It is in accordance with the natural laws we have noticed, 

 that the grasses in our meadows run out or change ; that 

 the timber-trees of the forest alternate — new species 

 springing up as the old ones decay, or are cut off; and 

 it is in accordance with these laws that the alternation of 

 crops has been adopted in all good farming. 



To simphfy and render the subject more plain, the 

 generality of tillage crops have been grouped into two 

 classes, differing essentially in their character, culture, 

 and influence upon the soil. These two classes are de- 

 nominated culmiferous crops, and leguminous crops. The 

 first is so named from culm, the stock or stem of grains 

 or grasses, usually jointed and hollow, and supporting the 

 leaves and fructification. Our intention is here not to 

 include the grasses. Culmiferous crops are termed rob- 

 bers or exhausters of the soil. This class includes 

 wheat, barley, oats, rye, Indian corn, tobacco, cotton, 

 &c. These are particularly exhausting during the pro- 

 cess of maturing their seeds. If cut green, or when in 

 blossom, they are far less exhausting. Leguminous crops, 

 strictly, are peas, beans, and other pulse ; but here the 

 group is intended to embrace, besides, all that are con- 

 sidered amehorating or enriching crops, as potatoes, tur- 

 nips, carrots, beets, cabbages, and clover. These last 

 are not only less exhausting than the culmiferous class, 

 as but few of them mature their seeds, and all, on ac- 

 count of their broad system of leaves, draw more nourish- 

 ment from the atmosphere than the narrow-leaved plants 

 of the other class, but they tend to improve the condition 

 of the soil, by dividing and loosening it, with their tap 

 and bulbous roots. For these reasons they are called 

 ameliorating crops ; and as they generally receive manure, 

 and are cultivated with the horse or hand-hoe, they are 

 peculiarly adapted to fit the soil for the culmiferous group 

 of crops. 



