Corn Growers' Association. 



345 



sequently it is to these three only that we need give special atten- 

 tion in a discussion of soil fertility. 



The accompanying table shows the actual amounts of these 

 three elements found in the surface seven inches of an acre in sev- 

 eral prominent Missouri soils as compared with a very fertile soil 

 as a standard. 



Nitrogen, 

 lbs. 



Phosphorus, 

 lbs. 



Potassium, 

 lbs. 



A very fertile soil contains. . 



Union ville 



Adrian 



Monroe City 



Victoria 



Lamar 



Billings 



Dixon 



Salem 



Truesdale (White Oak) 



Maryville (Rolling Prairie) . . 

 Malta Bend (River Bottom) 

 Maryville (Gumbo Bottom). 



5,800 



2,000 



5,300 



4,140 

 2,840 

 3,020 

 1,460 

 2,480 

 2,020 

 1,680 

 1,140 

 1,240 

 5,440 

 3,140 

 4,660 



785 



698 



628 



453 



445 



427 



400 



290 



440 



1,230 



1,590 



1,600 



6,706 

 5,080 

 5,578 

 4,583 

 3,835 

 814 

 569 

 590 

 660 



10,700 



12,530 



9,540 



It will be seen that both nitrogen and phosphorus are strik- 

 ingly lacking in most of these soil types, while potassium is usually 

 fairly abundant. It will be noticed, too, that since the nitrogen sup- 

 ply of all soils occurs in the vegetable matter or humus, those soils 

 that are blackest in color, such as the prairie of North Missouri 

 are consequently highest in total nitrogen, while the dry, gravelly 

 uplands of the Ozarks are lowest in nitrogen. The lack of phos- 

 phorus is most striking in the Ozark uplands also, although even 

 in the prairie of North Missouri the lack is plainly evident. 



It should be said regarding these analyses that while they do 

 not as many believe tell exactly what fertilizers will give best re- 

 sults on any particular season, for the reason that the season af- 

 fects the availability of the store of food which the soils contain, 

 yet they nevertheless indicate clearly where the soils are deficient 

 and what systems of farming one should adopt for the best ulti- 

 mate returns. I may say, too, that our results to date show a very 

 close agreement between these analyses and the produce which the 

 various plant foods bring. 



EXPERIMENTS ON THE NORTHEAST MISSOURI FLAT PRAIRIE. 



Monroe City Field. 



One of the first soils on which experiments were begun was 

 the flat prairie soil of North Missouri, found most typically in the 



