8 AGRICULTURAL RESEARCH AND THE FARMER : 



applies with as much force to agriculture as to any other pro- 

 fession. To the farmer, experience is undoubtedly an invaluable 

 asset, but agricultural practice, like everything else, changed with 

 changing times, and experience is robbed of half its value unless 

 supplemented by the knowledge which can only be given by 

 research into the hidden mysteries of plant growth. 



Xhe purpose of the Rothamsted Experimental Station is to 

 gain precise knowledge of soils, fertilisers, and the growing j^lant 

 in health and disease. We shall refer to the work on plant 

 diseases when we come to consider that subject in a subsequent 

 chapter, and at present will speak only of the investigations into 

 soils and the feeding of crops. Further, under the latter heading, 

 a large amount of work is done on the Rothamsted farm in testing 

 new fertilisers and comparing methods of cultivation and manurial 

 treatment. This work is well known to the agricultural public, 

 and as the prime purpose of the present publication is to explain 

 the more fundamental research work that is carried on mainly 

 in the laboratory, the valuable field experiments in progress will 

 be dismissed with this passing reference. 



The soil investigations now being conducted at Rothamsted 

 centre round two main problems which have a vital bearing on 

 practical agriculture. In the first place, how to provide the soil 

 with that supply of organic matter which we know to be of such 

 great importance ; secondly, how to cultivate the soil so that it 

 will provide the most efficient medium for the growth of crops. 

 To solve the former problem, a knowledge of the exact constitution 

 of the soil and of the precise part played by organic matter in 

 the supply of food to the growing crop is the first essential ; to 

 solve the latter, we need to know what the physical properties 

 of the soil are, how they are affected by varying conditions of 

 climate, and what are the respective influences of weather and of 

 soil constituents in producing that necessary preliminary to 

 successful crop production which is known to the farmer as tilth. 

 Bound up with this problem also is the question of implements of 

 cultivation, for in the absence of an exact knowledge of the 

 physical properties of the soil, the agricultural engineer cannot 

 be supplied with the information which he requires in order to 

 construct the ideal implements for carrying out the various 

 processes of tillage. 



Life in the Soil. 



In the first place, we will consider the enquiries into what may 



be termed the question of organic matter, and for the sake of 



convenience the subject will be treated under two main headings : 



(i) the study of the chemistry of the soil, and of the world of life 



