60 AMERICAN HUSBANDRY. 



in eight years. It would be good policy to have a 

 few acres in mangold-wurzel on a portion of the 

 fallow land, instead of turnips, to guard against 

 a scarcity of food in the spring ; this root is also 

 very valuable in the lambing season for ewes, as it 

 forces a great quantity of milk." 



The changing of one variety of wheat for another 

 is, we imagine, of little consequence ; but not so the 

 substitution of the fibrous-rooted for the tap-rooted 

 plants, or barley, wheat, and the grasses in succes- 

 sion. If the doctrine of the deposition of noxious 

 matter be correct, it must have reference more to 

 species than variety, and it should be to change in 

 this respect that the attention should be principally 

 directed. But, whether this doctrine be true or false, 

 the reasons for a rotation of crops are untouched ; 

 and we are confident that no farmer who views his 

 interests in their true light will discard the system, 

 or, for the sake of a dubious present profit, put at 

 hazard the certainty of permanent productiveness in 

 his soils. 



CHAPTER V. 



PLOUGHS AND PLOUGHING. 



Ancient Ploughs.— Modern Ploughs.— Ploughing.— Depth to 

 which Roots of Plants Penetrate. — Subsoil Ploughs. — Fall 

 Ploughing. — Deep or Shallow Ploughing. 



Perhaps the progress of civilization and the ad- 

 vances of agriculture are more clearly marked by 

 the history of the plough and its improvement than 

 in any other way : certain it is, that the state of ag- 

 riculture in any country can now be ascertained al- 



