128 



THE FERTILITY OF THE SOIL 



Plants, effect on soil 7 



Plants, suitability to soil con- 

 ditions 41 



Potassium salts and fertility 34, 

 121 



Protozoa in soil 26 



Root range 35 



Rotation of crops 61, 91, 104 



Sand dunes 119 

 Sandy soils 38, 101 

 Schloesing and Muntz 14 

 Schultz-Lnpitz system 112 

 Sheep and fertility 109 

 Soil sickness 37 

 Sourness 36 

 Structure of soil 10 



Temperature of soil 30 

 Townsbend's system 103 

 Tull's system 55 

 Turnips and what they did 56 



Waesland 110 



Warington 13, 15 



Warping 82 



Waste of fertility 63 



Waste land 88 



Water supply 27 



Weathering 2 



Whittlesea mere, reclamation of 



72 



Winogradsky 16 

 Wychwood, reclamation of 66 



CAMBRIDGE: PRINTED BY JOHN CLAY, M.A. AT THE UNIVERSITY PRESS 



