DRY FARMING CONGRESS. 



77 



comparatively simple, but they are not. They are continually combining 

 and recombining in ever-changing relations to each other and to the 

 modifiable factors; sometimes one group and sometimes another being 

 the controlling one. 



3. — When we consider that the modifiable factors are not only rela- 

 tively few in number, but that they can be controlled by man to only a 

 limited extent, and that their effect upon the peculiar combination of 

 unmodifiable factors existing at the time is problematical when modified 

 in any given direction, the difficulties and dangers involved in any attempt 

 to deduce any general principles governing the effects of various agricultural 

 practices calculated to so modify the soil conditions as to insure the 

 maximum yield of crops at once become apparent. 



4. — The above considerations lead us to an explanation of the fact 

 that although farming has been carried on in the Great Plains Area for 

 more than a quarter of a century, very little progress has been made 

 toward a solution of some of the simplest problems of farm practice, 

 such as the best time and depth of plowing, crop rotation, tillage, summer 

 fallowing, etc. They show also the utter futility of any attempt to es- 

 tablish a definite system of tillage based upon any limited experience 

 in restricted localities and under circumstances where at best only a 

 very few oi the many factors involved can be measured, such as has 

 been made by parties interested in the commercial exploitation of lands 

 in the semi-arid districts. 



5. — On the other hand we believe that the results so far obtained 

 at this station lend strong support to the belief held by those in charge 

 of this co-operative work that some very definite relations can be 

 established between methods and results which will be applicable to the 

 entire practice of agriculture in the semi-arid districts, if this work is 

 developed as it has been begun, by first attempting, so far as possible,, 

 to measure every factor, physical, chemical and biological, that enters 

 into the production of crops; and in the second place having a large 

 number of closely correlated rotations at each station, upon many of 

 which the same crop is raised under like conditions, thus affording an 

 opportunity for cross checking and averaging results so as to eliminate 

 many of the unknown factors which are likely to vitiate results where 

 only one or two fields are used. 



6. — Even after every precaution has been taken to eliminate errors 

 by exercising the greatest possible care in the selection of the land, the 

 laying ou,t of the plats, and the harvesting and weighing of the crops, and 

 by the correlation of rotation, duplication of plats, checking up results 

 obtained from crop yields by physical, chemical and botanical determina- 

 tions, and the continuation of the work under a definite system through 

 a long term of years, as has been planned for this station, it will not 

 be until the results of the work at Nortji Platte have been compared 

 with the results from a dozen or more other stations in the Gteat Plains 

 Area, as will be done by the Office of Dry Land Agriculture, U. S. 

 Department of Agriculture, that definite conclusions can be drawn con- 



