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^ MAY 18:344 ^ 



B. P. 1,-404. V, /y "W^ W 



>jgiied October 3, 7908. ^<^ 



United States Department of AmcMteLA^ Jg^ ' 



BUREAU OF PLANT INDUSTRY-Circular No. 15. 

 B. T. GALLOWAY. Chief of Bureau. 



THE FERTILIZING VALUE OF HAIRY VETCH FOR 

 CONNECTICUT TOBACCO FIELDS. 



By T. R. Robinson, 



Assistant Fhysiologist, Soil Bacteriologij Investigations. 



INTRODUCTION. 



In connection with the introduction of a leguminous cover crop on 

 tobacco lands in Connecticut it became at once desirable to know to 

 what extent such a crop would lessen the need for fertilizers, especially 

 those supplymg nitrogen. Many experiments, mainly based on analyses 

 of legumes, might be cited to show the amount of nitrogen which 

 legumes furnish to a succeeding crop. Their very disparity serves to 

 mdicate, however, that the results may be largely influenced by soil 

 and chmatic conditions, so that for any one locality the results obtained 

 elsewhere might prove misleading. 



ADAPTABILITY OF HAIRY VETCH TO TOBACCO FIELDS. 



Mr. A. D. Shamel, of the Bureau of Plant Industry, pubHshed in 

 1905, m cooperation with the Connecticut Agricultural Experiment 

 fetation, the prehminary facts in regard to "a new and valuable cover 

 crop for tobacco fields," namely, Russian or hairy vetch ( Vicia villosa) ^ 

 This legume was found to be resistant to cold, heat, and drought- 

 occupied the ground during the fall, winter, and spring; decayed rapidly 

 when turned under; and enriched the soil by its ability to "fix" or 

 utilize atmospheric nitrogen when properly inoculated-that is, when 

 the bacteria were present to cause the formation of root nodules. Unless 

 the bacteria were artificially supplied it was found that the desired 

 inoculation was lacking or very tardy on the tobacco lands of the Con- 

 necticut Valley.2 



iSee Conn. Agr. Expt. Sta. Bui. 149. 



2;*The roots of plants from inoculated seed bore many tubercles, some aggre- 

 gations of them being as large as corn kernels. When the seed was not inocu- 

 ated the roots bore few, if any, nodules and the growth of the plants was much 

 less vigorous." (Conn. Agr. Expt. Sta. Bui. 149, p 6 ) 



