SOIIv FERTIIvlTY. 21 



results, however, were not encouraging. A more recent and 

 more promising attempt has been to inoculate soils with the 

 particular germs which thrive upon the roots of alfalfa or other 

 special leguminous plants. This practice has merit when a 

 plant is introduced upon a soil where it has never been grown, 

 and where the particular germs which thrive upon that plant 

 are lacking. Unfortunately some of the methods of prepara- 

 tion have been unsatisfactory, and have tended to throw the 

 whole matter into disrepute. It should be remembered that 

 little is to be gained by introducing these germs into a soil where 

 they already exist, as, for instance, adding clover bacteria to 

 fields where clover thrives. In attempting to introduce a new 

 crop, like alfalfa or soy beans, however, a marked advantage may 

 be gained, if the method of handling is successful. Sowing and 

 harrowing in a little soil from a field upon which the particular 

 crop is successfully grown, is one of the most certain means of 

 successfully inoculating a new field. 



These, then, are the four fundamental factors of soil fertility, 

 — texture, moisture, plant-food and living organisms. To 

 secure the conditions which favor them all, means good tillage, 

 accompanied by underdraining if necessary, a systematic rota- 

 tion which adds liberally to the humus supply of the soil, and 

 thorough cultivation to maintain the moisture supply. A fertile 

 soil must be mellow and friable, in condition to admit air readily, 

 to take up moisture quickly and allow the surplus to drain away, 

 to hold a good supply for future needs, and it must not be so 

 acid as to prevent the work of the unseen germs within it. If 

 these conditions are met, artificial fertilizers, if needed, will give 

 their best results. 



