202 MISCELLANEOUS FARM SUBJECTS 



exceedingly thin films over the surfaces of the particles, its abound- 

 ing species of bacteria operating in the water on the decaying plant 

 substances and affecting the solution of the minerals, minute quan- 

 tities of mineral and organic compounds in the soil water, fungus 

 plants, and the ever acting and hungry roots of crops constantly 

 taking in from the soil mineral and nitrogenous food and giving 

 out solvents, make of this an almost bewildering maze of physical, 

 chemical and biological changes. It is not strange that scientists 

 are slow in arriving at an understanding of or that no one is now 

 prepared to comprehensively state the laws of fertility. The study 

 of the biological activities in the soil is throwing new light upon 

 the chemistry of fertility ; and the study of soil chemistry will con- 

 tinue to show many facts concerning the preparation and use of 

 plant food in the soil. 



It is well known that vegetable matter or humus improves 

 most arable soils. It at least improves soils that are somewhat run 

 down by grain growing. Wherever partially decayed manure or 

 roots are found in the soil, moisture is usually present, and such 

 material also permits a free circulation of air. The real value of 

 this condition of the soil is explained by the following facts. In 

 order to grow, plants must have food in a soluble form in contact 

 with their roots. Plant food is made soluble by the decomposition 

 of organic matter and disintegration of mineral matter. Disinte- 

 gration of mineral matter is aided very materially by the acids 

 formed by decomposition of vegetable matter. Decomposition of 

 organic matter in the soil takes place as the results of the action 

 of bacteria and the bacteria which render plant food available can 

 act only in the presence of air and moisture. 



By a rational rotation of crops the land is kept in far better 

 tilth than would otherwise be the case. The importance of the 

 presence of organic matter in process of decomposition is often 

 far greater than is generally supposed. Thus the occasional turn- 

 ing under of a grass or clover sod, or the plowing in of a green 

 crop, is generally followed by marked physical benefit. By this 

 procedure fresh food is introduced into the soil for the bacteria and 

 fungi, many of which are highly beneficial aside from their direct 

 aid in effecting the decomposition of the vegetable matter. (Univ. 

 of Minn. B. 109; S. Dak. Agr. Col. B. 79; R. I. Ex. Sta. B. 74; 

 Y. B. 1905.) 



Necessity of Rotation. That the fertility and productivity of 

 farm soils are rapidly deteriorating is a fact so well established that 

 it needs no confirmation. Even the rich soils of the Illinois prair- 

 ies have shown decided marks of decay, and this is true of the soils 

 of every State in the Union and every Province in Canada. The 

 question is being asked by nearly all farmers, "How can the worn 

 lands be most speedily and economically restored to their primi- 

 tive fertility?" This question is especially serious in the corn belt 

 section. With the kind of farming carried out on the better class 

 of farms, the crops that are grown and the live stock kept, rotation 

 is well nigh indispensable. The yields by the ordinary methods of 



