AGRICULTURAL UTILIZATION OF ACID LANDS. 133 
There is one other feature of the acid-soil question which merits 
the serious consideration of agriculturists. Recent investigators 
have shown that various fungi are able to fix and feed upon the 
nitrogen of the atmosphere, just as do the bacteria of the clover root 
tubercles and certain free bacteria of alkaline and neutral soils. One 
Swiss investigator, Charlotte Ternetz, has isolated from acid soils 
several fungi in which this faculty not only occurs but is developed 
to a high degree of efficiency. It has not yet been fully demon- 
strated that true mycorhizal fungi possess this faculty of nitrogen 
fixation, but there 1s much evidence that they do. Should this be- 
come definitely established, agriculture must recognize in the my- 
corhizal fungi a direct and powerful means of adding to the store 
of available nitrogen, and the culture of mycorhizal plants in acid 
soils will have a significance far beyond the mere value of the crops 
produced by them. 
CONCLUSION. 
In closing this paper the writer desires to impress on agricultural 
investigators (1) that soil acidity is not always an objectionable 
condition which invariably requires an application of lime, (2) that 
under certain economic conditions a complete system of acid-land 
agriculture 1s practicable and desirable, and (3) that the extent to 
which our cheap eastern acid lands can be utilized with small apph- 
cations of lime, or under some conditions without its use, is a legiti- 
mate and important subject for detailed investigation, from which 
may reasonably be expected results of far-reaching economic im- 
portance. 
DDITIONAL COPIES of this publication 
may be procured from the SUPERINTEND- 
ENT OF DOCUMENTS, Government Printing 
Office, Washington, D. C., at 5 cents per copy 
WASHINGTON : GOVERNMENT PRINTING OFFICE : 1913 
