101 



to 1-2 per cent., and in aluminous soils or 

 clays more abundantly. 



These constituents can only be deter- 

 mined, so far as actual proportions go, by 

 chemical analysis, and the terms already 

 employed — sand, clay, loam (a mixture of 

 clay and sand), lime humus — afford the 

 main criteria as to composition, either 

 chemically or physically. There may be 

 sandy loam or clayey loam also. Light 

 soils are sandy, heavy soils clayey, as a 

 rule, and wet soils are clayey or peaty ; 

 dry soils sandy or limey or calcareous. 



The physical properties depend on 

 texture, porosity, absorptive power to 

 retain water, heat retaining properties or 

 temperature. As regards texture the par- 

 ticles vary in size, from gravel or stones, 

 sand or grit, to clay. A mixture of clay 

 and sand with humus makes a properly 

 porous or ventilated soil. Sandy soils are 

 loose, porous, easy to work and warm ; 

 clayey soils heavy, retain water, and are 

 too close and cold. 



Light and heavy soils are also distin- 

 guished as degrees of tenacity. Sandy 

 soil is lighter than clay, which is heavy, 

 stiff, and difficult to work. Lime soils are 

 close, but do not retain water so much as 

 clays. Peat soils are light and porous. 



The retentive power of soils depends on 

 their texture. Clay soils are retentive, 

 and collect the soluble and insoluble 

 matter in rain water, ammonia, etc., and 

 absorb it. Whereas sandy soils do not do 

 this. Sandy soils absorb water more 

 freely than clays, but do not retain it. 

 Lime soils are intermediate. 



A dry soil is warmer than a wet soil, 

 hence sand is dryer than clay, and lime 

 soils are also warmer than clays. Well- 

 drained land is 3 deg. F. warmer than un- 

 drained land. Hence fruit-trees grow 

 better on warm than cold soils, as they 

 require good drainage. 



Now all these properties of the different 

 types of soil are important in considering 

 the different requirements of particular 

 fruit-trees. And such types are derived 

 from the various subsoils, which in turn 

 are the weathered surfaces of the natural 

 rocks or geological formations, of which 

 there are some 40 or 50 different kinds in 

 the British Isles. 



It is advisable to give examples of some 

 of these in order to indicate the regions 



where suitable soils may be expected to 

 occur. The outcrops of the rock may be 

 ascertained by referring to a geological 

 map of the British Isles. 



Clayey soils, with 95 per cent, clay, are 

 formed from the Kimmeridge Clay, Gault, 

 and London Clay, and a clay which con- 

 tains a fair amount of gravel and stones 

 occurs in the Boulder Clay, which overlies 

 the solid or older rocks over a great part 

 of England, north of the Thames Valley, 

 formed during the ice age. A less dense 

 clay, or loamy clay, with 25 per cent, clay, 

 is formed also by the London clay. Marly 

 soil (20 per cent, lime salts), occurs on 

 the chalk, chalk marl, Keuper marl. 

 Loamy soils (70 per cent, clay), are derived 

 from the Bracklesham Beds, Middle Lias, 

 and brickearths in valleys. Loam of a 

 gravelly nature is also found where the 

 boulder clay is of this nature, as in 

 central and East England. Sandy loam 

 (40 per cent, clay), is formed from the 

 Bagshot Beds, Upper Greensand, Old 

 Eed Sandstone. Silt is a fine earthy or 

 muddy kind of sand, and found where 

 there is alluvium in river valleys, or as 

 warp in estuaries. Silty loam is another 

 product of alluvium; sandy or siliceous 

 soils are derived from blown sand, of the 

 sea coast, etc., Bagshot sand, Lower 

 Greensand. Sandy soil, which is siliceous 

 and calcareous, is provided by blown 

 sand. Middle Lias, midford sand; brashy 

 soil is formed by Cornbrash, and other 

 Oolitic rocks. Earthy ferruginous soils are 

 found on Carboniferous Limestones, as a 

 residue, and sandy and loamy ferruginous 

 soils are also afforded by the Middle Lias 

 ironstone, Corallian, Keuper, and Bunter 

 sandstones. Peaty soils are formed by 

 present day peat on mountains, moorland, 

 iDogs and marshes; gravelly, pebbly soils 

 are derived from valley and plateau 

 gravels, Blackheath beds, Bunter pebbles. 



To turn, now, to where some of these 

 formations are developed, and where 

 fruit-trees grow best upon them. It is to 

 be noted that such formations differ as 

 regards texture in different districts, and 

 other considerations, such as proximity to 

 sea, altitude, rainfall, temperature, make 

 one district better than another, and in 

 studying suitable conditions, meteoro- 

 logical conditions must be taken into 

 account, as well as the soil. 



