1010 EXPERIMENT STATION RECORD. 



our methods of tilling- and managing the soil as will enable us to 

 increase, and, if possi])le, give direction to the activities of the chem- 

 ical and biological (bacterial) forces which are incessantl3^ at work in 

 it, and cause them to change potential plant foods into available forms 

 in greater almndance than they do by means of our present methods." 

 He reasons that '•'as the soil is known to be in general well supplied 

 with potential plant foods — sometimes within 8 inches of the surface 

 with enough for some hundreds of crops — it would be a far more 

 philosophical course to make it our aim to learn how to make the 

 greatest possible use of these potential plant foods than to devote our 

 energies almost exclusively, as until lately we have been doing in 

 our held experiments, to the study of hand feeding our crops Avith 

 manures." He does not contend that we shall be able to dispense 

 altogether with manures and fertilizers, Init believes that "the poten- 

 tial plant foods which are already in the soil can l)e ihade to contribute 

 far more largely, and that they should )»e made to contribute as much 

 as possible to the nourishment of our crops; and that eventually, under 

 ordinary conditions and for ordinary (as distinguished from intensive) 

 farming, it will only be found necessary to hand feed crops with such 

 plant foods as the soil is naturally oi' may become by cropping insuffi- 

 ciently provided with, or particular crops require in special a))un- 

 dance." 



This proposition is not a novel one, but comparatively little experi- 

 mental work has yet proceeded from it as a basis. The importance of 

 the biological agencies at work in the soil has probably only been 

 hinted at. The desirability of a bettei' knowledge of them as a means 

 of progress was forcil)ly pointed out l)y Professor Conn in his recent 

 book on Agricultural Bacteriology. Professor Conn says: 



"The whole problem of the soil fertility is inextricably woven with 

 bacterial fermentation. From the origin of the soil, through its use 

 b}' plants and the subsequent destruction to their original condition 

 of the products formed, we find nearly every step accompanied by 

 bacterial action. The continued fertilit}^ of the soil is thus associated 

 with bacterial life. In the future the problem of the proper treat- 

 ment of soil for the use of agriculture will be, in a very large degree, 

 a problem of the proper control of bacteria. Agriculturists must 

 learn to stimulate the bacterial actions which are advantageous and 

 check those which are disadvantageous, if the}^ would insure the con- 

 tinuance of soil fertility." 



Referring to the possibilit}" of influencing chemical changes in the 

 soil, Mr. Farrer ventures the suggestion that "it may be we shall 

 learn how, either b}^ particular methods of treatment, or by the addi- 

 tion of certain substances, to give direction to, as well as increase, the 

 chemical activit}^ amongst the constituents of the soil. If we could 

 learn, for instance, how to make soluble some of the insoluble silica 



