220 



and injuring the growing plants. Some lands will produce neither 

 ferments nor crops, while limestone lands are everywhere very fertile. 

 Hence, small quantities of lime or some other base, are essential to nitri- 

 fication. 



7. The most essential condition of all, the presence in the soil of some 

 organic matter containing nitrogen. If the soil be deficient in this, it 

 must be artificially supplied in some form, stable manure, cotton seed 

 and meal, dried blood, tish scrap, etc. The use of stable manure and 

 compost as a manure is doubly valuable They not only supply directly 

 the plant food, but nitrifying organisms of a particularly vigorous 

 character in great numbers, and the latter, when incorporated with the 

 soil, together with their progeny, exercise their activity upon the inert 

 nitrogen of the soil, when the more nitrifiable portions of the manure 

 are exhausted. Hence, stable manure and compost produce fertilising 

 results beyond what was expected from the quantity of plant food con- 

 tained therein. Even our poorest soils are tound by chemical analyses 

 to contain plant food amply sufficient for remunerative crops, and this 

 addition of ferments" by the compost renders much of it available. 

 It may be asked here whether much of the infertility of some of our 

 soils may not be due to the absence of these ferments and, if so cannot 

 they be supplied ? In reply, I say, certainly Different soils vary 

 greatly in the quantity and vitality of these ferments, and frequently 

 good results have followed the thin sprinkling of a rich garden loam 

 over a poor field. This has been frequently done on reclaimed swamp 

 lands, rich in vegetable matter, sterilised by long inundation A dose 

 of lime and a small quantity of ferment scattered over them, have 

 quickly converted them into fertile ils. 



But science has gone further and prepared the way commercially for 

 another class of fertilisers which are now on the market. Professor 

 ISobbe, Director of the Experiment Station at Tharandt. Saxony, is 

 now preparing for the m rket " pure cultivation of the bacteria." The 

 preparations consist of " colonies of the bacteria on agar gelatine enclosed 

 in sealed bottles, each one of which contains organisms enough for half 

 an acre of land." These preparations are diluted in water, and sprinkled 

 over the soil, or over the seed to be sown, or diluted in water and then 

 mixea with about fifty pounds of the soil, and the mixture scattered 

 over the land. He has named the preparations from the roots of 

 seventeen different legumes, " Nitragin," and they are for sale on the 

 market. 



Besides producing nitric acid from organic matter through nitric 

 ferments, the leguminous plants, particularly our own cow pea and some 

 cryptogams, have through the colonies of bacteria which infect their 

 roots, the power of converting free nitrogen of the air into plant food, 

 and it is also believed that other organisms which are capable of oxidiz- 

 ing free nitrogen of the air, exist in soils that are devoid of organic 

 nitrogen. 



As I have remarked, these beneficial bacteria are accompanied by 

 ferments inimical to agriculture; eg., a ferment has been discovered 

 which will decompose nitric acid, and has been styled " denitrifying 

 ferment." A study of this ferment has developed the gratifying fact 



