12 THE LAND AND ITS PROBLEMS 



of the soil. A passage in Pliny advises the farmer to 

 " sow next year's wheat crop in the field where he has 

 just gathered his beans, vetches, lupins, or such other 

 crop as enriches the soil." 



The chief plants of the leguminous order, besides those 

 mentioned above, are peas, clovers and lucerne. Of 

 these lucerne is the plant that endures the longest ; a 

 field may remain under lucerne for from five to nine 

 years in England, and in some other countries for an 

 almost unlimited time. 



The Romans in their turn acquired their knowledge 

 of agriculture from the ancient Egyptians, who under- 

 stood the value of leguminous crops and of rotation of 

 crops at a very early age. 



A very advanced agriculture was practised in the 

 Mediterranean countries from prehistoric times ; this 

 development was the natural result of a dense population 

 living on fertile land limited in area ; high cultivation was 

 essential in order to feed the dense population. 



It is interesting to note that, in quite another part of 

 the world, the Chinese understood the use of leguminous 

 plants as early as looo B.C. 



This knowledge of the use of leguminous plants, and 

 of the immense value of the rotation of crops, is one of 

 the definite landmarks in the development of agriculture ; 

 and the recovery of this knowledge is of comparatively 

 recent date in England. 



THE FIFTH TO THE SEVENTEENTH CENTURIES 



When the Roman occupation of England ended, all 

 attempt at agriculture ceased. Little was done even in 

 the Middle Ages, which was indeed a period of darkness 

 as far as the cultivation of the land was concerned. 



