60 MASS. EXPERIMENT STATION BULLETIN 196. 



a part of the harvested portion of the crop or left behind in the stubble 

 and roots, on plots S than on plots N, thus reducing materially the neces- 

 sity for application of nitrogen to crops in later years. 



Bibliography. 

 Wm. p. Bro'oks. Reports of the Progress of the Experiment. Hatch 

 Experiment Station annual reports: 14, p. 48; 15, p. 145; 16, p. 

 147; 17, p. 147; 18, p. 32. Massachusetts Agricultural Experi- 

 ment Station annual reports: 19, p. 54; 20, p. 55; 21, Pt. II, p. 

 36; 22, Pt. I, p. 44; 23, Pt. I, p. 48; 25, Pt. I, p. 32. 



