24 EXPERIMENT STATION. [Jan. 



The results of eliemieal analysis of soils do not, as a rule, afford a 

 satisfactory basis for determining manurial requirements. The chem- 

 ist, it is true, can determine what the soil contains, but no ordinary 

 analysis detennines with exactness what proportion of the several ele- 

 ments present is in available form for the crop. Indeed, there is no 

 such thing as a constant ratio of availability. While one crop may find 

 in a given soil all the plant food it requires, another may find a shortage 

 of one or more elements. Further, on the very same field one croja will 

 find an insufficient amount of potash, another may find enough potash 

 for noiTaal growth but insufficient phosphoric acid, and a third may 

 suffer from an insufficient supply of nitrogen. 



Most of our soils are of mixed rock origin, and as a rule possess 

 similar general chemical characteristics, provided they have been 

 farmed under usual conditions. The manurial and fertilizer require- 

 ments are detennined more largely in most instances by the crop than 

 by peculiarities in the chemical condition of the soil. The chemical 

 analysis of soils, then, does not, as a rule, afford results which have a 

 value commensurate with the cost, and as a rule this station will not 

 make such analyses unless the soil differs widely from the nonnal in 

 natiu-al characteristics, or has been subjected to unusual treatment of 

 such a nature as to probably greatly influence its chemical condition. 



In some cases the corresj^ondent reports that his crop is diseased and 

 that he desires a chemical analysis in order to ascertain what is the 

 cause. The chemical composition of the soil may in some instances exer- 

 cise a controlling influence in determining a condition of health or 

 disease, and is never unimportant from the standpoint of vigorous, 

 normal and healthy growth ; but in the case of most diseases the imme- 

 diately active cause is the presence of a parasitic fungus, and this 

 fungus is usually capable of fixing itself upon the plant whatever may 

 be the composition of the soil. A knowledge of the chemical composi- 

 tion of soils, therefore, will not make it possible to advise such manurial 

 or fertilizer treatment as will insure immunity from disease. 



It will be noted that the corresponrlent quoted evidently be- 

 lieves that the chemical composition of the soil will determine 

 its suitability for different crops. The chemical composition 

 may not be without importance in determining what the soil 

 is fitted to produce, but the physical characteristics of the soil 

 and subsoil, as affecting drainage, the capacity to hold water, the 

 capacity to conduct water from below upwards, texture and 

 aeration, are of much greater importance in determining what 

 crops the soil is fitted to produce. It will be noted that the 

 correspondent expresses a willingiiess to pay the cost of analysis. 

 Very many express themselves to that effect. The fact that 



