EXPERIMENT STATION BULLETINS. 



219 



In 1904 a similar investigation was carried forward with cowpeas. The re- 

 sults are inserted here before comments on the foregoing table are made. 



COMPOSITION OF THE DRY MATTER OF COWPEAS WITH AND WITHOUT NODULES 



ON THE ROOTS. 



COMMENTS ON THE TABLES. 



The attention is first directed, naturally to the relative amounts of protein in 

 the forage of the inoculated and not inoculated plants. The leaves and stems 

 together of the inoculated soys carry 17.38 pounds of protein per hundred weight 

 while the not inoculated have but 11.08 pounds per hundred weight as the meaa 

 of the two years. Note that in both years the per cent of protein was higher 

 with the inoculated and that when both years are taken together the content of 

 protein was 56.86 per cent greater in the inoculated plants. 



With the cowpeas the inoculated plot was 47 per cent richer in protein tham 

 the one with plants free from nodules on the roots. 



The importance of this fact is apparent. While little difference could be de- 

 tected between the several plots during the growing season, either in color or 

 general thrift, the chemist found a wide variation in the values of the harvests 

 as to either feeding or manurial constituents. If the presence of the nodules 

 insures no greater yield of these legumes on a fairly fertile soil, if the farmer 

 reaps no heavier harvest where the nodules are, he may expect a richer harvest, 

 better alike for his cattle and his soil. 



It is notable that the roots of the uninoculated plot are richer in protein than 

 those of the inoculated. The nodules were removed, of course, from the roots 

 of the inoculated specimens. These nodules have the following composition: — 

 Protein, 26J.9 per cent; Nitrogen, 4.19 per cent; Potash, 2.05. The nodules of 

 Cowpeas were analyzed separately and were found to be made up as follows. — 

 Protein, 24 39 per cent; Nitrogen, 3.90 per cent; Phosphoric acid, .96 per cent. 



As to why the roots of the uninoculated legumes contain a greater per cent of 

 nitrogen than those of the inoculated, the answer is not obvious. It may be that 

 the material furnished by the germs in the nodules is more quickly carried by 

 osmosis through the cell walls and therefore sooner transferred to the growing 

 parts of the plants. 



