JAMAICA. 



BULLETIN 



OF THE 



BOTANICAL DEPARTMENT- 



New Series.] OCTOBER, 1896. ^"lO . 



SOIL FERMENTS IMPORTANT IN AGRICULTURE . 



"By Dr. W. H. Wiley, Chief of the Division of Chemistry, 

 TJ. S. Department of Agriculture, in Louisiana Planter. 



VITALITY OF THE SOIL. 



Not many years ago the soil was regarded by the agriculturist as dead, 

 inert matter, devoid of all vitality. The theories of fertilisation of the 

 soil were based upon this idea, and the methods of culture were con- 

 ducted according to the same theory. The only vital thing which the 

 farmer considered was the growing crop itself, and there was no sus- 

 picion of the relation existing between the vitality of the crop and of 

 the living organism of the field. The reader of the agricultural 

 literature of to-day does not need to be told how all this has been 

 changed in the last twenty years. The soil is no longer regarded as 

 dead and inert matter, but is known to be so permeated with living beings 

 as to entitle it to be considered a living mass. The parts of the soil 

 which are not endowed with life now receive their highest significance 

 as the environment of the living organisms which they contain 

 and which they may help to nourish. The plant which forms the 

 growing crop receives its nourishment through the media of the air and 

 soil, but this nourishment must uniergo a process of digestion before it 

 becomes available as plant food, similar to that suffered by the food 

 which nourishes animals. Indeed, the purely mineral, inorganic foods 

 of plants are probably not always absorbed as such, and must undergo a 

 decompositon before they are assimilated. A striking instance of this 

 is shown injthe case of silica, an important plant food and a type of inert 

 mineral matter. Silica is highly insoluble and apparently the least 

 suited of the mineral constituents of the earth to enter the vital or- 

 ganisms of the plant. Yet not only do we find it in the tissues of the 

 mature plant, but also, strange to say, in greatest abundance in those parts 

 of the plant organisms, viz. : the leaves, most remote from the sources of 

 supply. It is evident from this that the highly insoluble salica of the soil 

 must undergo a complete solution in order to be carried by the juices of 



