[SHUTT A charron] NITROGEN-ENRICHMENT OF SOILS 



63 



ISTothing ' more conclusive in the way of evidence could be wished 

 for. The practical field tests confirm in the most emphatic manner 

 the results obtained by chemical research and show beyond dispute the 

 great value of clover as a fertilizer. 



While it is the purpose of this paper to discuss 'simply the nitrogen- 

 enrichment of soils through the growth of legumes, the 'fact must not 

 be lost sight of that there are many other ways in which this plan of 

 " green 'manuring " benefits the land. The turning under of the grow- 

 ing crop, such as clover, adds a large amount of vegetable matter which 

 eventually becomes humus, one of the soil's most important constituents. 

 Besides acting as Nature's storehouse for the nitrogen — for humus and 

 nitrogen are always associated, and, as has been observed they increase and 

 decrease together — humus furnishes by its decay a considerable quantity 

 of mineral plant food, lime, potash, and phosphoric acid, 'and these are 

 undoubtedly Ulcerated in forms readily available to growing crops. 

 Further, humus has two valuable functions — it supports the bacterial 

 life of the soil and thus in a very important and direct way is con- 

 nected vnth the preparation of the food for crops. It also materially 

 affects the physical condition of the soil, chiefly in making it more re- 



