COVER CROPS. 293 



one or two may be removed for hay, though by this plan 

 the full benefit of the crop cannot be secured. The last 

 cutting should not be so late as to prevent seed forma- 

 tion, for if once well established, the crop will reseed itself 

 year after year, if well managed. 



The amount of nitrogen collected, up to the time of 

 the formation of flower buds, is shown by the following 

 unpublished analysis made by Prof. W. A. Blair, of the 

 Department of Chemistry, in the University of Florida: 



Weight in pounds of dried stems and leaves per acre 3,489.15 



Weight in pounds of dried roots per acre 105.85 



Weight of nitrogen per acre in stems and leaves 90.71 



Weight of nitrogen per acre in roots 10.02 



Total nitrogen in roots, stems and leaves per acre... 100.73 



But a single cutting is represented in the above analy- 

 ses. If allowed to grow throughout the whole summer, 

 or if cut once or twice and the crop allowed to return to 

 the soil, the amount of nitrogen collected during the 

 entire season would probably be increased one-half. 



A straight, strong tap-root with numerous laterals 

 is produced. These penetrate well into the soil, loosen- 

 ing and opening it to a depth of twelve to fifteen inches, 

 or even more. The nodules are comparatively small, 

 rounded, smooth, and under favorable conditions, pro- 

 duced abundantly. Figure 69 shows the nodules natu- 

 ral size and also gives a fair idea of how plentifully they 

 are formed on the roots. 



From five to ten pounds of seed are required per acre, 

 but, as already noted, when once seeded, sowing is not 

 necessary for the next season. The seed should be scattered 

 broadcast on freshly harrowed ground, and a second har- 

 rowing then given. If it is deemed necessary to 



