80 EGYPTIAN AGRICULTURE. 



to the application of manures ; " black " because they 

 contain little of the light coloured sand. Sandy and 

 sandy-loam soils are "light," "warm," "dry," "active" 

 and " red." Salt loam and sandy soils may be sweetened 

 by washing ; or, in the case of sand, better by warping ; 

 stiff clay must be otherwise treated. 



The fertility, or size of the crops obtained from a 

 soil, depends on the composition of the soil, the power 

 possessed by the soil to fix plant foods, the absence of an 

 excess of acids and salts, on the texture, water capacity, 

 capillary power, permeability, tenacity, and on the presence 

 of good, and absence of bad, micro-organisms in the soil. 

 Hence it is impossible to definitely say that loam is in- 

 variably better than sand or clay soils. In wet climates 

 heavy clays are most objectionable as their wetness 

 prevents their tillage ; in dry countries except where there 

 is a plentiful supply of water sandy soil is of least value 

 for cropping. In cropping it is usual to plant lupins on 

 the poorest soil, barley on poor soil, and wheat on the 

 strongest clay ; but this is a purely financial arrangement, 

 the best crop of lupins, barley, and wheat, being obtained 

 from the rich loam soils. 



The cultivation of the soil is undertaken to ensure the 

 production of larger crops by increasing the amount of 

 available plant food, and by improving the physical pro- 

 perties so that the plant will be better able to get and 

 absorb this food. The more food a plant obtains from 

 the soil, the greater is the amount of atmospheric food 

 (carbon dioxide) it can take up for the use and profit of 

 the farmer. Cultivation in its wider sense includes all 



