PRACTICAL APPLICATIONS 257 
leguminous crops are raised and plowed under for the sake 
of the nitrogen in them, this being called “ green manuring,’* 
a practice which was carried on for a long time before the 
reason for its value was learned. 
Figure 246. — Effect of Inoculation on Garden Peas. 
No. 1, uninoculated. No. 2, inoculated. 
