Xo. 4.] KEEPING UP FERTILITY. 79 



farmer cannot change, except within narrow limits, the 

 relative proportion of coarse and fine materials in his soil, 

 he can, by intelligent, thorough and careful culture, do much 

 to insure profitable returns from his use of manures and 

 fertilizers. It is folly to lavish these while withholding the 

 work necessary to insure fine tilth both before planting the 

 seed and during the growth of the crop. 



Let it be understood, then, at the outset, that one of the 

 most im[)ortant methods of keeping up the fertility of the 

 soil is by thorough preparation and careful culture. Not 

 only do these insure such physical conditions that manures 

 and fertilizers applied will do their best, they also favor the 

 action of the beneficial natural agencies which are constantly 

 at work under favorable conditions converting the raw 

 materials of the soil into available food for plants. The 

 great importance of this action becomes evident when we 

 consider the chemical composition of the soil. 



At this point it is necessary to say that, in considering 

 the composition of soils, plants, manures and fertilizers, I 

 shall confine my attention to the three constituents, — 

 nitrogen, phosphoric acid and potash. It is well known 

 that all contain numerous other constituents, such as lime, 

 magnesia, soda, silica, etc. ; but, it being generally admitted 

 that the natural supply of these is so liberal that our crops 

 rarely suffer because of a deficiency of any of them, it seems 

 best to leave them out of consideration, inasmuch as a 

 thoroughly satisfactory treatment of our subject even thus 

 restricted is an impossibility in the time available. 



In connection with experimental work carried on under 

 my direction during the last six years and in preparation for 

 the Columbian Exposition I have had a considerable number 

 of soils from different parts of this State and of dift'erent 

 geological characters subjected to analysis. The partial 

 results of some of this work I desire to bring to your atten- 

 tion, not in percentages as reported from the laboratory, but 

 worked out in pounds i)er acre, in which form their signifi- 

 cance becomes much more apparent ; and for comparison 

 therewith I present similar details for a few prominent field 

 crops. These figures I shall have occasion to use later also 

 in considering the application of manures and fertilizers. 



