458 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



of the root I have described to you here, the function of giving 

 to water the power to dissolve inorganic matter in the soil. If, 

 as already exemplified in a former lecture, a quantity of common 

 Boil, Avith water, carbonic acid and ammonia, be placed in two 

 vessels of water, and in one of them be also introduced the root 

 of a growing plant, the portion of inorganic matter dissolved in 

 the latter vessel, will be found to be twenty-five times greater 

 than that dissolved in the vessel without the root. 



It is for this reason that a green fallow is so important to the 

 Boil. The growing crop give^ the humidity, the moisture cover- 

 ing every substance in its vicinity, the power of being a better 

 solvent of inorganic matter, and it is thus storing up in an ad- 

 vanced state the inorganic constituents of the soil as food for 

 the next crop ; and particularly when that crop is itself suffered 

 to decay in the soil, as in plowing under a clover. We find that 

 the sulphate of lime has the power to retain the gaseous pro- 

 ducts of decomposition, beyond the power of water to waste 

 them away; the power to absorb and retain them against all 

 conditions other than the presence of a root of a growing plant. 

 When the soil is deficient in these constituents, clover is caused 

 to grow in it, and send down its roots, ramifying, as we know to 

 a great depth, performing the functions I have described through 

 large areas. Thus it lifts through subsoil, and up to the surface of 

 the soil, large quantities of progressed inorganic pabulum, which 

 may be readily appropriated by the ensuing crop. If that clover 

 be plowed under, we have the conditions consequent upon the 

 addition to the soil of all the progressed material that crop 

 has gathered. In addition to this, the decay of the clover in 

 the soil secures many mechanical advantages. It occupies space. 

 From the gradual decay of this matter, there is necessarily a 

 slight motion ; the particles occupying less space as they change 

 their condition. Thus, they freely admit atmosphere and moisture, 

 giving to the soil that peculiar property described by Hayes and 

 others as " ferment." No manure has material value that will 

 not give this to the soil. All these advantages arise from the 

 Bowing of clover. 



This is not the only green crop we may use. In some districts 

 we grow buckwheat for that purpose, and the process may be 

 repeated twice in the same season, and in some districts oftener. 

 Field peas, in some soils, form an admirable grain crop, because 

 the vines decay first in the centre of the straw, when buried 



