THE SOIL IN RELATION TO PLANT GROWTH 125 



{Chrysanthemum Leucanthemum) are among the more obvious plants on 

 these neglected fields ; the only relics of the past are the field names 

 and the high ridges or " lands " made years ago to facilitate drainage. 

 But recently marked improvement has set in. Drainage is gradually 

 being attended to, whilst additions of lime and phosphates (as basic 

 slag) have markedly improved the herbage, favouring the development 

 of white clover {Trifolium repens) and the pasture grasses, and crowding 

 out the weeds. Potassic fertilisers are not usually needed. Only in 

 the dry eastern counties has the old arable cultivation survived. 



Sandy soils are formed of large silica particles deficient in colloidal 

 matter, and therefore possessing little power of cohesion, or of retain- 

 ing water or soluble salts. Hence they tend to be dry, loose, and poor 

 in soluble substances — "hungry," the practical man calls them. Their 

 behaviour towards vegetation depends very largely on their position, 

 their depth, and the nature of the subsoil, these being the factors that 

 determine the water supply to the crop. The water supply is usually 

 satisfactory when the surface soil contains sufficient clay and not too 

 much coarse sand and gravel, and rests on a deep subsoil containing 

 rather more of the finer particles. It is a further advantage if other 

 land lies higher and furnishes a supply of underground water. In 

 such cases the land is nearly always cultivated ; it yields early crops 

 of high quality rather than heavy crops, the tendency to drought in- 

 ducing early maturation, while the absence of stickiness makes sowing 

 an easy matter at any time. Fruit, potatoes, and market-garden pro- 

 duce are often raised, and high quality barley is also grown. The 

 winter feeding of sheep on the land is a common way of fertilising, but 

 crops must be sown early, or the fertilising material is washed out 

 unused, and the young roots have no time to strike into the subsoil 

 before the surface layer dries out. High farming is the only profitable 

 way of dealing with these soils ; any carelessness in cultivation lets in 

 hosts of weeds, such as poppies, knot-weed (Polygonum aviculare), spur- 

 rey {Spergula arvensis), sorrel, horsetail, convolvulus, creeping butter- 

 cup, and others. Crops should follow each other in rapid succession, 

 any interval being a period of loss ; under good management two or 

 even three market-garden crops can be secured in the year, while 

 in purely farming districts catch crops should always be taken. 

 Organic manures are very necessary to increase the water-holding 

 capacity : sheep-folding or green-manuring are, therefore, very desirable. 

 Calcium carbonate is often needed and is better applied as ground 

 chalk or limestone than as lime. Potassium salts are beneficial and 

 may be added as kainit ; nitrates often give remarkable results, but 



