266 Bacteria in Relation to Country Life 



Small wonder, then, that farming saw no progress, 

 and that bare fallows and their various modifications re- 

 tained a prominent place on the farm. It was customary 

 in many places to fallow the land after two successive 

 crops of wheat, or after a crop of beans, followed by 

 wheat. The necessity of bare fallows was questioned, 

 however, as early as the seventeenth century, particu- 

 larly after the more extensive cultivation of clover and 

 Qf turnips. The work of Jethro Tull in England gave 

 an impetus to a more intelligent consideration of the 

 question. The implements of tillage that he devised 

 or improved helped to undermine the faith in the neces- 

 sity of bare fallows. 



Towards the middle of the eighteenth century there 

 was much discussion and a strong division of opinion on 

 this question. The partisans of fallowing were evidently 

 losing ground, however, for the practice became less 

 prominent as time went on. On many farms where 

 bare fallows were still- retained, they were resorted to 

 once in five, six, or seven years, instead of once in two 

 or three years. Thaer in Germany was particularly 

 prominent in the latter half of the eighteenth century 

 in teaching the unwisdom of fallowing and in advocating 

 systematic rotations and the introduction of hoed crops 

 in such rotations. 



Fallow crops. — Bare fallows were thus gradually 

 superseded by the so-called fallow crops, that is, either 

 hoed crops, like turnips, potatoes, or swedes, or green- 

 manuring crops like clovers, vetches, lupins. In the 

 case of the hoed crops, the seed was planted in drills 

 or rows and the land could be cleaned of weeds. The 



