x.] APPLICATION OF SOIL SURVEYS 339 



But the chief application of a soil survey in this 

 country lies in the information that can be affdrded 

 as to the use of manures ; enormous economies might 

 be effected in the bills of almost every farmer using 

 artificial manures, if the latter were properly adapted 

 to his soils and crops. Farmers are often recom- 

 mended to carry out manurial trials upon their own 

 farms until they have ascertained the peculiarities and 

 specific requirements of the soil, but advice of this 

 kind treats altogether too lightly the somewhat delicate 

 business of conducting field experiments. Putting aside 

 the mechanical difficulties attending a trial of this kind, 

 and the overpowering effect of minor inequalities of the 

 ground and other accidental conditions which so often 

 nullify the experimental treatment, it is rarely that 

 the farmer will be found able to arrange a scheme of 

 experiment likely to give information of permanent 

 value. If one may judge from the published accounts 

 of many field experiments carried out in this country 

 by public bodies, which so often show a misappre- 

 hension of the points really at issue, there is every 

 probability that the individual farmer will be as often 

 misled as guided by the results of his own experiments. 

 The design and conduct of field experiments must be 

 left to the expert, who surveys the subject from a wider 

 standpoint, who can compare various trials, and is in a 

 position to continue them for a period of years, rejecting 

 at any early stage a considerable proportion which are 

 inevitably vitiated by some concealed local peculiarity. 

 A body of experts conducting a soil survey and field 

 experiments simultaneously in the same area and co- 

 ordinating their results, can give advice of the most 

 definite character as to the scheme of manuring to be 

 adopted for each soil type. The fundamental factor 

 requiring consideration in this matter, and brought out 



