2 INTRODUCTORY 



per ton, when potatoes grown upon the Lincoln warp 

 soils are at 60s., and those from the black soils of 

 the fen country are only fetching 45s. to 50s. This 

 extra price for the red land potatoes is due to 

 the fact that they can be cooked a second time, 

 after cooling, without changing colour, whereas the 

 ordinary potato is apt to blacken a little when once 

 cooked and allowed to grow cold. 



The scientific study of soils is concerned with the 

 differences indicated above ; its endeavour is to obtain 

 such a knowledge of the constitution of the soil and the 

 part it plays in the nutrition of the plant, as will make 

 clear the cause of the inferiority of any given piece of 

 land, and ultimately enable the farmer to correct it. 

 The problems involved are far more complex than 

 they appear ; at first sight nothing would seem easier 

 than to make a chemical analysis of the soil and find 

 out in what respects it differs from another soil of 

 known value ; then the deficiencies or the excesses, as 

 compared with the good soil, could be corrected by suit- 

 able manuring. The matter is not, however, quite so 

 simple, for if on the one hand the soil can be considered 

 as a great reservoir of plant food which can be recovered 

 in crops, on the other hand it is equally correct to 

 regard the soil as a manufactory, a medium for trans- 

 forming raw material in the shape of manure into 

 the finished article the crop. In new countries where 

 virgin soil is being exploited, and in districts where the 

 systems of agriculture are primitive, the former point of 

 view is the correct one ; nothing is given to the soil 

 beyond that amount of labour which will enable some 

 of its inherent value to be realised in a crop. Little by 

 little the capital, which may be practically boundless, 

 as in the great wheat lands of Manitoba, or initially 

 little enough, as on a Connemara heath, is being drawn 



