MAINTAINING THE SOIL FERTILITY 293 



possible that the factors above discussed, if properly 

 applied, could liberate the latent plant-food of the 

 soil and gather all necessary nitrogen for the plants. 

 Such an equilibrium, could it once be established, 

 would possibly continue for long periods of time, but 

 in the end would no doubt lead to disaster; for, 

 unless the very cornerstone of modern agricultural 

 science is unsound, there will be ultimately a cUmi- 

 nutioii of crop producing power if continuous crop- 

 ping is practiced without returning to the soil a goodly 

 portion of the elements of soil fertility taken from it. 

 The real purpose of modern agricultural research is 

 to maintain or increase the productivity of our lands ; 

 if this cannot be done, modern agriculture is essen- 

 tially a failure. Dry-farming, as the newest and 

 probably in the future one of the greatest divisions 

 of modern agriculture, must from the beginning 

 seek and apply processes that will insure steadiness 

 in the productive power of its lands. Therefore, 

 from the very beginning dry-farmers must look 

 towards the conservation of the fertility of their 

 soils. 



The first and most rational method of maintaining 

 the fertility of the soil indefinitely is to return to the 

 soil everything that is taken from it. In practice 

 this can be done only by feeding the products of the 

 farm to live stock and returning to the soil the ma- 

 nure, both solid and liquid, produced by the animals. 

 This brings up at once the much discussed question 



