JAMAICA. 



BULLETIN 



OF THE 



BOTANICAL DEPARTMENT- 



New Series.] NOVEMBER, 1896. V ° L 



SOIL FERMENTS IMPORTANT IN AGRICULTURE, 



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

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

 ( Continued). 



UTILITY OF TILLAGE. 



Among the influences which favour the process of nitrification tillage 

 of the soil must be mentioned. A thorough breaking up of the soil 

 and of the upper layers of the subsoil is necessary to the aeration, which 

 is an indispensable condition to the progress of nitrification. The cul- 

 tivation of the soil, therefore, in this way not only makes it possible 

 for the rootlets of the plants to extend to a greater distance, and thus 

 secure larger quantities of foid, but actually increases the available 

 quantity of nitrogenous food in the soil. In connection wirh thorough 

 drainage the best tillage of the soil tends to make available its stores of 

 inert nitrogen. 



NECESSITY FOR LIME. 



Since the final action of the nitrifying organisms results in the pro- 

 duction of nitric acid, it is highly important that the soil contain some 

 substance capable of combining with this acid, and thereby preventing 

 its accumulation in a free state. The activity of these ferments is di- 

 minished by the presence of an acid and increased by a moderately alka- 

 line environment. If the acid be allowed to accumulate to a certain 

 point, not only is the activity of the ferments suspended, but a positive 

 injury may be done to a growing crop. All practical farmers know- 

 how poorly sour lands respond to cultivation, and this injurious influ- 

 ence is due not only to the action of the acid upon plant growth, but 

 also in a high degree to its effect in preventing the evolution of the 

 nitrifying organisms. It is well known that a soil which has an abund- 

 ant content of carbonate of lime is, as a rule, fertile. The value of 1 me 

 as a fertilising agent in many soils is well attested, yet it is certain that 

 this favourable effect is not due to the fact that an additional amount 

 of lime is necessary for plant food. Soils are rarely found which do 

 not contain an abundant supply of lime for all the nutritive needs of 



