10 



The Weekly Florists^ Review* 



Afbil 4, 1012. 



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SOILS; WHAT THEY j»s 

 ■^ CONTAIN AND DO 



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A ROSE OBOWER'S NOTES. 



The Origin of Soil. 



What is soil? Soil is the home of the 

 roots of the plant. Soil is the store- 

 house for that part of the food which 

 the plant takes in through its roots. 

 Soil is the laboratory, or kitchen, where 

 the food is prepared. And this work 

 goes on unceasingly. Lastly, soil is a 

 support to hold the plant firmly in its 

 place. 



But what is soil? Soil is finely di- 

 vided rock, as can be readily seen with 

 a microscope, clay being the finest and 

 sand and gravel the coarsest of the 

 divisions. In between the sand and the 

 clay we have what are generally known 

 as loamy sand, sandy loam, loam, clayey 

 loam and loamy clay. These divisions 

 are based upon the size of the soil 

 grains and the different percentages of 

 each size in a given soil. They are, 

 of course, not arbitrarily fixed, there 

 being unnumbered variations of soils. 



Now, if we consider soils as broken 

 and decomposed rock, the first question 

 that comes to eur minds is: How and 

 when were the rocks which originally 

 covered the face of the earth converted 

 into soil? Certainly ages and ages be- 

 fore man appeared on the earth. In 

 fact, before animal life of any kind 

 could exist there must have been vege- 

 tation; and vegetation of the higher 

 forms could not exist on bare rock. 

 Probably the commencement of the dis- 

 integration was coincident with the ap- 

 pearance of plant life in the lowest 

 form. 



Geologists tell us that the earth was 

 once a molten mass; also, that the water 

 which now composes the oceans was 

 probably in the form of a dense vapor 

 which surrounded the red-hot earth. 

 Naturally, the earth began to cool and, 

 as it cooled, it contracted. The result 

 of this was that the surface subsided 

 in some places and wrinkled in others, 

 thus producing the sea basins, valleys 

 and hills. When the surface had 

 cooled sufficiently (and this cooling was 

 hastened by the vapor in the air) the 

 vapor condensed and fell as rain or 

 snow, and thus began to wear or weath- 

 er the rock. Frost and heat assisted 

 the water in disintegrating and break- 

 ing up the surface. Some time after 

 the surface had cooled sufficiently, 

 vegetation began its existence. Mrst 

 came almost microscopic forms, the 

 mosses and lichens which are able to 

 extract nourishment from almost any 

 rock. These by their death and decay 

 formed a thin film of vegetable matter 

 on the rock and a stronger growth took 

 place, which in turn died, decayed and 

 gave way to a still stronger and higher 

 form of vegetation; and so on till grass, 

 shrubs and even trees were able to ex- 

 ist. This decayed vegetable matter in 

 the soil is called humus. And this hu- 



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A paper by Alfred Burton, rose grower, read 

 before the Florists' Club of Philadelphia, April 2, 

 1912. 



mus helps to disintegrate the rock by 

 holding moisture and by supplying acids 

 which increase the solvent powers of 

 the water on the rock. When a soil 

 contains much of this humus it is called 

 a vegetable mold. Eich garden soils 

 are good representatives of this class. 

 A soil that contains vegetable matter 

 that has only partly decomposed under 

 water is called a peaty soil. Such soils 

 are found in swamps and bogg and are 

 generally sour and need to be aerated 

 and limed before using. 



Importance of Humus. 



While organic matter, or humus, is 

 by no means indispensable to plant life, 

 and though it is a debatable question 

 whether plants derive any nourishment 

 from it direct, it is of great importance 

 in enabling the soil to hold water, in 

 making the soil more friable and easily 

 worked, and in supplying carbonic acid, 

 which feeds the plant and acts on the 

 soil, dissolving and making available 

 other foods, such as soda, potash and 

 magnesium, which are held in an insol- 

 uble state in the soil. Humus also 

 gives the dark color to the soil, which 

 enables it to absorb the heat rays of 

 the sun more readily and thus warm 

 up more quickly in the spring. 



True clay is composed of silicate of 

 alumina, but the term clay in agricul- 

 ture is employed rather loosely, being 

 given to soils that contain a large 

 percentage of impalpable rock dust with 

 little of the true clay present. Some 

 authorities give the following percent- 

 age composition of the various soils: 



Clay or 

 impalpable matter. Sand. 



Heavy clay 75 to 90% 10 to 25% 



Clay loam 60 to 75% 25 to 40% 



Loam 40 to 60% 40 to 60% 



Sandy loam 25 to 40% 60 to 75% 



Light sandy loam 10 to 25% 75 to 90% 



Sand to 10% 90 to 100% 



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Light and Heavy Soils. 



These percentages are by weight of 

 the dry soil. 



We hear the terms light and heavy 

 applied to soils. These terms have no 

 reference to the weights of the soil, but 

 are used in reference to the mechanical 

 condition. A light soil is one that con- 

 tains considerable sand, falls apart and 

 works easily. A heavy soil is one that 

 is stiff and tenacious, with more clay 

 than sand. It is a fact that a heavy soU 

 actually weighs less than a light one. 



A tenacious or adhesive clay soil can 

 be greatly improved by the addition of 

 sand, lime or vegetable matter, which 

 tend to separate the particles of clay. It 

 is' this adhesiveness of clay which causes 

 heavy soils to crack when drying. Clay 

 expands much more than light soil's 

 when wet and shrinks upon drying and, 

 owing to the adhesiveness of the par- 

 ticles of which it is composed, the 

 shrinking causes the cracks to appear. 

 These cracks are, naturally, injurious to 

 the roots of the plants, breaJiing and 

 pulling them apart. Sand does not 

 change its bulk by wetting or drying. 

 Likewise, a sandy soil can be improved - 

 mechanically by the addition of clay, 

 lime or vegetable matter. Lime has the 

 peculiar power of lightening heavy soils 

 and also of making light soils hold to- 

 gether better, bringing the two extremes 

 to a happy mean, as it were. 



The Composition of Soils. 



The general chemical composition of 

 soils is extremely similar, owing to the 

 general mixing of the soil ingredients 

 that has been going on since soil first 

 began to form, through the action of 

 water dissolving and carrying material 

 from place to place, through the action, 

 of streams, floods and glaciers, of bur- 

 rowing animals, worms, etc., of the wind 

 and even plants. 



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Flowers are More than Mere Merchandise. 



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