How LEGUMES HELP THE FARMER 163 



and take into consideration the serious losses of nitrogen which are always 

 in progress in soil, and especially in a rich soil." 



Some of the nitrogen in the soil comes from the ammonia and nitric 

 acid in the air brought to the soil in rain or snow. In localities distant 

 from large manufacturing towns this has been shown to be very small. 



Some believe that plants can assimilate through their, leaves the gaseous 

 ammonia in the air, but this has not as yet been proved to be a fact, though 

 the late Dr. Gray thought that they ought to do so, though he admitted 

 that he had never proved that they do. Schlosing found, however, that moist 

 soil freely exposed to the air, took up nitrogen at the rate of about 38 pounds 

 per acre per annum in the surface, mainly in the form of ammonia. But as 

 his experiments were conducted in Paris, the amount is entirely too high for 

 the open country 



TAKING FREE NITROGEN FROM THE AIR THROUGH PLANT GROWTH. 



We have of late years learned a great deal in regard to the acquisition 

 of nitrogen from the air by leguminous plants. All the scientists now 

 admit that the microscopic fungous plants that form the tubercles on the 

 roots of leguminous plants, do in some way not as yet understood fully, get 

 the free nitrogen of the air and leave it in the soil in the shape of organic 

 nitrogenous matter. The leguminous plant, like all other plants, can absorb 

 nitrogen from the soil through the action of its root hairs, but it has the 

 further advantage over other kinds of plants, that it can get, through the 

 agency of the microbes in the tubercles on its roots, a still further and greater 

 supply than the soil affords to other plants. The microscopic organisms 

 may exist in the soil where there are no plants of clover or other legumes, 

 but no experiments have shown that they can fix the free nitrogen of the 

 air in the soil until they become attached to the roots of the leguminous 

 plant. But, as we have said, there is no need for us, as farmers, to go into 

 the investigation of the biological processes by which the plants do get the 

 nitrogen of the atmosphere. Their life history has been too briefly studied 

 as yet to demonstrate the exact process. Sufficient for the present purpose 

 is the fact that the organic nitrogen is thus fixed in the soil and becomes 

 available for succeeding crops. 



NITRIFICATION OF ORGANIC MATTER IN SOILS. 



Having located the free nitrogen of the air, through the action of the 

 root tubercles of the leguminous plants, let us consider how this organic 

 matter becomes food for the plants, or how any organic matter in soils is 





