136 



SOIL CONDITIONS AND PLANT GROWTH 



The Interpretation of Mechanical Analyses-^ 



The properties of the various fractions have already been given in 

 Chapter III., but some little practice is necessary before they can be 

 used for the interpretation of an analysis. A few illustrations are there- 

 fore given from Hall and Russell's survey of Kent, Surrey, and Sussex 

 (123): the data are set out in Table LIII. 



The Chilworth soil contains so little clay and fine silt and so much 

 coarse sand that it has very little power of retaining water. As it lies 

 too high to obtain any seepage water from the neighbouring formations 

 it is dependent on the immediate rainfall, and is therefore not in culti- 

 vation but has always been heath land. Owing to its bad constitution 

 and its high situation it could not by any known method be made 

 suitable for farming. 



Table LIII. — Mechanical Analyses of Soils and Their Interpretations. 



The Shalford soil lies lower down and has a better water-supply, 

 less coarse sand and more clay and fine silt. But its water-holding 

 capacity and its retentive power for manures are still very low ; artificial 

 manures are of much less value than organic manures, and the best 

 treatment of the land is to grow green crops and fold them off to sheep. 

 It is better suited to special purposes like the production of malting 

 barley or market-garden crops than to ordinary mixed farming. 



The Goldstone soil contains more clay and fine silt, and has there- 

 fore better power of retaining water and manures, and is more produc- 

 tive and more generally useful. But as the coarse sand exceeds the 

 clay in amount it is still distinctly light ; it responds better to organic 

 than to artificial manures and suffers rather in droughty weather in 



'■ See Appendix for Methods of Analysis and p. 53 for details as to dimensions and 

 composition of fractions. 



