APPENDIX. 167 



BULLETIN No. 16. 



INVESTIGATION OX THE FORAGING POWERS OF S0:ME 

 AGRICULTURAL PLANTS FOR PUOSPUORIC ACID.* 



Prof. Walter Balentine. 



Of recent investigations in plant nutrition those establishing the 

 fact that leguminous plants are able to gather a portion of their 

 nitrogen either directly or indirectly from the free nitrogen of the 

 air are by far the most important, both from the scientific and the 

 practical stand points. 



These investigations settle a question that has attracted the 

 attention of agricultural chemists for half a century. On the prac- 

 tical side the results enable us to say, that it is possible, by grow- 

 ing and feeding to farm animals such plants as peas and clover, to 

 increase the stock of nitrogen for manurial purposes without resort- 

 ing to the various expensive commercial nitrogenous materials. 



Stating the results of these investigations concisely, it has been 

 found that the leguminous plants are able to forage on the atmos- 

 phere for a portion of their nitrogen. Other plants either possess 

 this power to a much less degree or not at all. If we look for a 

 reason why this family of plants has attracted so much attention 

 from scientists we find it in the fact that some of its members, the 

 clovers especially, have been found in practical farming to be 

 plants which by their growth on the soil, apparently leave it richer 

 in plant food than before, and that farmers are actually able to 

 produce more of grass, grain and potatoes when clover is used 

 as one of the crops in rotation. It was to learn why a plant 

 that takes up such large quantities of nitrogen as clover, should 

 still leave the ground in a better condition for succeeding crops, 

 that the sources of supply of nitrogen to the leguminous plants 

 have been so carefully studied. 



The value of the results of this work to the agriculture of the 

 world cannot be over-estimated. There are, however, other prob- 

 lems in plant nutrition which deserve as careful study as the nitro- 

 gen question and which may yield results of equal practical impor- 

 tance. 



*This buUetin is an extract from the report of Prof. Balentine in the Station 

 report for 1893.— W. II. J. 



