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The soil to which the farmer entrusts his seed must possess certain qualities. Then the 

 plant must be able to extract a sufficient quantity of moisture from the soil, although ,this 

 need not be abundant. Clays and heavy loams are the best soils on which to grow wheat ; 

 but with skilful farming and selection of the proper varieties, good harvests are obtained on 

 light sandy soils. If the ground is too wet, the corn lacks vigour, and the production of seeds 

 is small. If, on the other hand, sand predominates, the ground is too permeable and does 

 not hold the quantity of moisture that is absolutely necessary for the growth of the wheat, 

 which then thrives very badly. It will not do, says the farmer, to accommodate oneself to the 

 soil, but the soil must be accommodated to the plant. When necessary, its nature may be 

 modified by the addition of different kinds of manure, that is to say, by adding the elements 

 which it lacks. Thus, it is necessary to add lime to sandy soils, and as a rule marl — that is, 



a mixture of chalk and clay 

 — is used for the purpose. 

 If one has to deal with a 

 soil in which clay is lacking, 

 very clayey marl should be 

 taken. The element that is 

 added to the soil must not 

 only modify its physical 

 nature by giving it greater 

 density, or, on the contrary, 

 greater looseness, but it must 

 also, by its chemical com- 

 position, increase the chance 

 of successful cultivation. 

 Marl fulfils both these 

 conditions. It sometimes 

 happens that the sub-soil 

 contains the elements which 

 are wanted in the top soil. 

 In that case the land must 

 be deeply ploughed, the sub- 

 soil being brought to the 

 surface and thoroughly 

 mixed with the upper layer. 

 To put the matter briefly, 

 the essential elements are 

 the indispensable elements of 

 These elements have to be 



Chalk 



Sand 



Clayey Sand 



Clay 



THE RESULTS OF WHEAT-GROWING UPON VARIOUS SOILS 



(1) sufficient but not excessive moisture, (2) lime, and (3) 

 plant food, such as nitrogen, phosphoric acid, and potash 

 furnished by natural or chemical manures, if it is proved by analysis that the soil does not 

 contain them in sufficient quantities. Thus, the fundamental principle of a rational culti- 

 vation of wheat is to know the physical and chemical conditions of the soil thoroughly, a 

 knowledge which enables the farmer to modify its composition in a judicious manner. The 

 great advantage of chemical manures is that it is possible to give greater richness to the soil 

 by the addition of small quantities of material, but they should be used with care. They 

 cannot, however large the quantities added, replace the natural manure, that is, farmyard 

 or, as it is often termed in the tropics, pen-manure. The latter is the manure par excellence, 

 improving both the physical and the chemical conditions of the soil, and increasing its water- 

 holding powers, owing to the organic matter or humus it adds. 



The land on which wheat is to be grown must be thoroughly cleaned, for the plant is easily 

 choked by weedy growths. Therefore, wheat is usually sown on a field on which a crop has 



