11 



scientific laboratory, liberal use is made of statistical methods 

 which allow the investig-ation of cases where several factors vary 

 simultaneously. Thus in the crop investigations a larg-e number 

 of field observations are made ; these are then treated statistically 

 to ascertain the varying- degrees to which they are related to other 

 factors — such as rainfall, temperature, etc. — and to indicate the 

 probable nature of the relationships. Thus the complex problem 

 becomes reduced to a number of simpler ones susceptible of 

 laboratory investigation. 



It has been found desirable to widen the scope of the work by 

 repeating- some of the more important experiments elsewhere, and 

 some twenty centres in different parts of the country have been 

 selected for this purpose. 



In October, 1921, the Station undertook, so long as its funds 

 should allow, to carry on the continuous wheat and barley experi- 

 ments at the Woburn Experimental Farm, till then conducted by 

 the Royal Agricultural Society, and Dr. Voelcker gives his 

 services as Honorary Local Director. In December, 1922, E. D. 

 Simon, Esq., generously placed his Leadon Court farm at the 

 disposal of the Station for experimental purposes. This is being 

 used as a large scale test of the soiling system for keeping dairy 

 cows (see p. 26) . 



REPORT FOR THE YEARS 1921-22 



In order to appreciate properly the Rothamsted experiments, 

 it is necessary to understand the purpose for which they are 

 carried out. This purpose is to discover the principles underlying 

 the great facts of agriculture and to put the knowledge thus 

 gained into a form in which it can be used by teachers, experts 

 and farmers for the upraising of country life and the improvement 

 of the standard of farming. 



The most fundamental part of agriculture is the production of 

 crops, and to this most of the Rothamsted work is devoted. On 

 the technical side the problems fall into three groups, concerned 

 respectively with the cultivation of the soil, the feeding of the 

 crops, and the maintenance of healthy conditions of plant growth. 

 The subjects will be taken in this order. 



THE CULTIVATION OF THE SOIL. 



Cultivation has been reduced to a fine art, and a good farmer 

 independent of financial considerations could obtain very satisfac- 

 tory results without consulting- the scientific worker. In practice, 

 however, costs dominate the situation, and efforts are continuously 

 being made to cut them down. Scientific investigation of all 

 cultivation processes therefore becomes necessary. This is done 

 in the Physical Department under Dr. Keen ; the effects produced 



