xii INTRODUCTION 



proportion of these elements it contained, it was felt that 

 the causes determining fertility were now at last firmly 

 grasped. The large increase in the supply of artificial 

 manures helped forward these novel views by making their 

 practical application easy. At the present day agricultural 

 chemistry still to a considerable extent monopolizes the field, 

 although a fuller knowledge of the facts of agriculture has 

 not borne out the theory to which we have referred. The 

 part of agricultural science which is most prominently brought 

 before our farmers in rural classes and lectures is still the 

 need and application of artificial manures. 



There can be no doubt that the neglect of the physical 

 conditions of the soil as a subject of study, and in consequence 

 as a subject of teaching, has done much to hinder the appre- 

 ciation of science by practical men. The experienced farmer 

 knows the overwhelming importance of a proper texture 

 of the soil for the profitable culture of each crop. His 

 scientific teacher has, however, little to say on this subject, 

 while he freely recommends the use of expensive manures 

 which a proper culture of the soil might render unnecessary, 

 and which must fail to yield a profitable return if a favourable 

 physical condition of the soil is absent. The farmer feels 

 that this teaching is out of touch with the experience he has 

 gained on the farm ; he also frequently finds that the plan 

 suggested is not a financial success. He therefore charac- 

 terizes the advice given as 'theoretical/ and concludes that 

 science is not a safe guide for the farmer. 



A soil may be rich in all the elements of plant food, and 

 yet be quite infertile. If seeds are to germinate in a soil, 

 or if roots are to develop in a healthy and vigorous manner, 

 there must be a suitable soil climate. The conditions as to 



