VALUE Or THE SOUTHERN PEA. 261 



to the quantity of the crop given to the soil. That cause, I presume, 

 will be found partly in the greater product and quantity of residue 

 to the acre than is left by most other crops ; but still more because 

 of the greater quantity of azote contained in the residue of roots 

 and stubble, as well as of the crops consumed as forage, or left to 

 be ploughed under, and in both cases, though in different ways, 

 serving as manure to the land. 



Of grain crops, or any others which take all their contents of 

 azote from the soil, and, if sold or removed from the farm, those 

 which have taken up and removed the most azote from the land, 

 must be the most exhausting of its fertilizing principles. And such 

 would be the leguminous crops, far beyond all others, if they came 

 under the conditions named, as they contain much the largest quan- 

 tities of azote. As they are known by observation to be among the 

 least exhausting, even when removed from the farm, that alone 

 would strongly indicate, what Boussingault's experiments have 

 proved, that these crops take a portion, and probably the larger 

 portion, of their azote from the atmosphere. * Of course, when re- 

 turned to the earth as manure, the azote so drawn from the air is 

 so much of supply of the richest principle, in addition to all others 

 contained, in common with other vegetable substances. We can 

 supply barn-yard and other animalized and azotized manures to our 

 farms only in limited and insufficient quantities. But by ploughing 

 in leguminous manuring crops, azote may be furnished to much 

 greater extent. 



Field peas, such as are raised in England, and in our Northern 

 States, are varieties of and very like to the kinds we know here only 

 as garden vegetables. These field peas contain even more azote 

 than clover does. Lucerne is also superior to clover in that respect, 

 and European field beans not inferior. All these plants are un- 

 suited to our climate, or unprofitable for culture on extensive 

 spaces. 



But we have a leguminous plant, in numerous varieties, native 

 to our country, and little known except in Virginia and the more 

 Southern States, which, as a green manure, and meliorating crop, 

 is scarcely inferior to clover and for some qualities, and always in 

 more southern regions, is preferable to clover. This is our southern, 

 or "corn-field pea," as commonly called, from being most generally 

 raised as a secondary crop among corn. In truth it is not a pea, 

 but a bean* Of this plant, I know of no chemical analysis. But 



* Miller's Gardener's Dictionary states a sufficiently plain distinction 

 between beans and peas, by describing the seeds of the former as " kidney- 

 shaped," and the latter as "roundish." The only pea known to me as a 

 cultivated plant, other than our European garden peas, has very small and 

 "roxindish" pale green seeds, in a black pod. Even this is more like the 

 vetch (vicia sativa) or our bad weed the "partridge pea," as to seeds and 



