62 



HATCH EXPERIMENT STATION. 



[Jan. 



bacteria, and only those which did made vigorous growth. 

 The next year, as already reported, about one-half of the 

 plants apparently possessed nodules and made vigorous 

 growth early in the season. Later all seemed to acquire 

 the ability to make use of the atmospheric nitrogen which 

 these nodular bacteria give. The crop of this season has 

 been extremely vigorous from the very first. The rapid 

 growth of this legume in early spring seemed to indicate 

 its possible value as a cover crop for green manuring ; and 

 to test this point one square yard (believed to be average) 

 was harvested at each of three different dates, and a deter- 

 mination of dry matter and of nitrogen contained therein 

 was made. The results calculated per acre were : — 



Date. 



neight 

 (Feet). 



Dry Matter 

 (Pounds). 



Nitrogen 

 (Pounds). 



June 6, 

 June 15, 

 July 10, 



3,661.6 

 3,961.7 

 7.573.0 



136.8 

 130.2 

 192.5 



The crop was in full bloom at the time the last cutting 

 was made, but it goes on blooming freely for almost the 

 entire summer. 



Corn for the silo may here be planted up to the middle 

 of June, with a good prospect of success ; and, as will be 

 seen, previous to that date the sweet clover makes a large 

 growth and contains a heavy amount of nitrogen. The 

 amount of this element at the date of the second cutting is 

 equivalent to that contained in about 6 cords of rich manure. 

 To what extent, however, this nitrogen has been taken 

 from the soil, and to what extent from the air, our experi- 

 ments afford us no means for determining. Kiihn has 

 pointed out that the acquisition of atmospheric nitrogen by 

 plants of the clover family takes place most abundantly in 

 the later stages of their growth ; and that, if they be 

 ploughed under immature, we can hope for but little gain 

 in that element. Our experiment, then, is not conclusive, 

 as yet, as to the value of this clover as a green manuring 

 crop. Since, however, being sown in the latter part of July 



