FAHMERS' INSTITUTES. 395 



is correspoudiugly limited, but when they are present in suflicient quantity and 

 in avaihible form, if the physical conditions of the soil and the climate are 

 favorable, any crop can be grown and brought to perfect maturity. Tiiey are 

 the chemical agents of j^^ttnt growth. In tlie entire absence of either lime or 

 magnesia, or potash, or sulphates, or phosphates, no ])lant can grow, much less 

 mature its seed. 



In studying the results of chemical analysis of the soil, we should fix our 

 attention mainly u))on these indispensable ash elements of plant growth. In 

 the following table I omit the mechanical agents of the soil, and present only 

 the sum of ash elements contained in one hundred parts of soil : 



1. River Raisin bottom lands, culti- 



vated forty years 7.17 



2. River Raisin bottom lands, virgin 



soil 7.58 



3. Burr-oak wheat land. Saline 4.33 



4. Prairie soil, never plowed, Cass 



Co 4.99 



5. Prairie soil, cultivated 30 years, 



Cass Co 3.98 



6. Soil from South Haven 2.47 



7. Gilmore, Isabella Co 2.72 



8. Warren, Midland Co 2.94 



9. Midland, Midland Co 6.6G 



10. Sheridan, Clare Co 1.55 



11. Chase, Lake Co 2.76 



12. Grant, Clare Co 5.37 



13. Webber, Lake Co 1.90 



14. Evart, Osceola Co 3.56 



15. Eden, Mason Co 1.98 



16. Eden, Mason Co 5.46 



17. Lake City, Missaukee Co 5.76 



18. St. Louis, Gratiot Co 2.45 



19. BayCity, Bay Co 3.04 



20. Grand Traverse, Grand Traverse 

 Co 3.26 



21. Greenville, Montcalm Co 3.12 



22. Colfax, Mecosta Co 5.33 



23. Benzonia, Benzie Co 2.76 



24. Gaylord, Otsego Co 1.76 



25. Agricultural College garden 3.56 



26. Agricultural College vineyard... 6.11 



27. Agricultural College field No. 8.. 5.56 



28. Tawas, Iosco Co 3.12 



29. Big Rapids, Mecosta Co 5.16 



30. Sherman, Wexford Co 2.35 



31. Elk Rapids, Antrim Co 3.03 



If we reject from this list the exceptionally rich bottom lands of the Raisin 

 (1 and 2), and of the Tittabawassee (9), and the exceptionally poor land (10, 

 13, 15 and 24), taking the average of the burr-oak land of Washtenaw county 

 and the prairie soils of Cass county as a basis of comparison (4.43), we find 

 that the average of all the rest of the soils in this list differs from this high 

 standard of soil excellence by only 58 hundredths of one per cent. All the 

 soils of this list (with the four exceptions) contain a large excess of ash ele- 

 ments beyond the requirement of any crop that may grow upon it. Soil No. 

 1 from River Raisin bottoms, has been cultivated forty years without manure, 

 yet, in 1876, it produced 83 bushels of shelled corn to the acre. 



In the case of the four exceptional soils, while the relative amount of ash 

 materials seems small, the absolute amount to the acre is large. Take No. 10, 

 which is the lowest in the list, having only 1.55 per cent of ash elements; fix 

 your eye upon potash .54 and phosphoric acid .15 percent, these substances be- 

 ing most important in the production of cereal crops; we find that an acre of 

 this soil taken to the depth of 12 inches, contains 10,800 pounds of potash 

 and 4,000 pounds of phosphoric acid ; yet 30 bushels of wheat remove less than 

 22 pounds of potash and 34 pounds of phosphoric acid. It will thus be seen 

 that even the poorest of these soils cannot be called chemically barren, because 

 they contain all the necessary ash elements of plants and in quantities suffi- 

 cient to sustain remunerative crops. If they are unfruitful it must be because 

 of unfavorable physical conditions, or because the ash elements are not in an 

 available form. 



KELITION" OF THE SOIL TO WATER. 



One prime condition of vegetable growth is water. No matter what the 

 chemical composition of a soil, or what its physical properties, nothing can 



