186 THE PRINCIPLES OF 



The second year of the rotation will almost always be 

 devoted to grain, the kind of grain depending on the nature 

 of the soil. The grain crop will be followed by a fodder crop 

 for the third crop. Then there will be another grain crop 

 during the fourth year, and it is possible that we may then 

 have recourse to the fallow, in which case we have a four- 

 course rotation, the fallow commencing a fresh series or new 

 rotation. In other cases the succession of crops proceeds 

 further. For example, the Norfolk rotation is a familiar 

 instance of what we have just been considering, that is, 

 roots followed with barley, followed with clover, followed 

 with wheat, followed again with roots as the commencement 

 of a fresh series or rotation. * What is sometimes called the 

 Holderness rotation is an example of a more prolonged 

 course, as, for example, when roots or fallow are followed with 

 wheat, followed with clover, followed with wheat, followed with 

 beans, followed with wheat, which is a six years' rotation. 

 The period which elapses between the fallowings limits the 

 length of the rotation. Upon poor land, fallows must be 

 frequent, especially where a somewhat exhaustive system of 

 cropping is pursued. Thus we have the three-field course, 

 that is, fallows every third year fallow, wheat, beans. Upon 

 a large number of soils the four-course rotation may be 

 adopted, and on richer soils a six years' rotation, as already 

 explained. Upon fertile clays we may go a step further, 

 and place a seven or eight years' interval between the 

 periods of fallowing. 



It is convenient to separate between rotations suitable for 

 heavy lands, and rotations which are suitable for light soils. 

 Most of our soils may be conveniently classed in one of these 

 divisions, either as heavy or light. In planning rotations for 

 heavy lands we ought always to be careful to select crops 

 which affect heavy lands. All kinds of land will grow all 

 kinds of crops, but there is a suitability, and in our capacity 



