v.] BARREN SOILS 99 



been brought into cultivation but remain in open 

 common and waste, may still contain 6 to 10 per cent, 

 of clay, but the sand fractions and particularly the coarse 

 sand, constitute something like three-quarters of the 

 whole soil. Such soils can retain no water for the 

 service of the crops upon them, nor for reasons that will 

 be seen later can they retain any plant food : they are 

 poor in the chemical sense, but barren chiefly because 

 of their drj-ness, even with the evenly distributed rain- 

 fall of Great Britaia 



