112 The Control of the Soil [pt. ii 



much of the soluble matter: sometimes indeed so much 

 that even weeds will not grow but only patches of moss 

 which decay to a black acid substance entirely unsuited 

 to most plants : such patches can be seen frequently on 

 the Bagshot sands in Surrey. 



Where there is a fair admixture of silt the movement 

 of the water is retarded, and on moving aside the top 

 two or three inches of soil the lower part is found to be 

 quite moist even in dry weather. In these cases plants 

 will grow well and a special type of treatment has been 

 evolved to suit them. 



In the first place the movement of the water has to 

 be still further retarded, and regular additions of organic 

 matter are therefore necessary. Secondly, lime has to 

 be added regularly except in certain special cases where 

 the soil lies at the foot of a long gradual slope and re- 

 ceives an underground drift of hard water from above. 

 Lastly, fertilisers have to be added in small but frequent 

 doses when the crop needs them. When these pre- 

 cautions are taken sandy soils will grow almost any 

 crop, but they especially favour the development of 

 roots and tubers so that they are well adapted to 

 potatoes, carrots, parsnips and nursery stock; further, 

 they give good quality barley and useful but not large 

 wheat crops. They are not suited for grass unless the 

 water table happens to be only 3 or 4 feet from the 

 surface in which case they may carry magnificent pas- 

 ture : some of the very best Romney Marsh pastures are 

 on sand. Otherwise the grass burns up badly in the 

 summer time owing to lack of water. 



Sandy soils tend very much to form pans, and care 

 has to be taken to prevent this by occasional use of the 

 subsoiler. 



