142 



In the air-dried material the vines weighed from three to seven and 

 one half times as much as the roots, the average being six times. Such 

 variations are not surprising in observations on so small areas. 



The commercial values of the valuable fertilizing ingredients in vines, 

 roots, and stubble, taking the average of the four samples and assum- 

 ing the phosphoric acid to be worth 7J cents, the potash 5 cents, and 

 the nitrogen 19^ cents per pound, are computed to be, vines, $29.90; 

 roots and stubble, $2.67 ; total, $32.57 per acre. 



Loss of nitrogen in vines by lying on the ground. — Samples of dry vines 

 which had lain on the ground during the fall and winter, were collected 

 in the last weeks of December and January, and the percentages of 

 nitrogen determined. The leaves had mostly disappeared, and it is 

 noted that the data do not suffice for exact comparison of the amounts 

 of nitrogen in the green vines as harvested in October and dried in the 

 laboratory, with the amounts in the corresponding or dried materials 

 as gathered from the ground in winter; or show how much of the nitro- 

 gen lost from the plants by loss of leaves, leaching, decay, or other- 

 wise, had been taken and held by the soil. The results of the nitrogen 

 determinations were as follows : 



Percentages of nitrogen in air-dry material. 



From these experiments and from results of late research regarding 

 the acquisition of nitrogen from the air by leguminous plants, the fol- 

 lowing conclusions are drawn : " (1) Cow-pea vines contain a large per- 

 centage of phosphoric acid, potash, and nitrogen, the three valuable 

 constituents of commercial fertilizers, and are especially rich in nitro- 

 gen, which they accumulate directly or indirectly from the atmosphere 

 and furnish as a fertilizer to other crops. (2) In these experiments 

 the vines weighed about six times as much as the roots, and were about 

 eleven and one fifth times as valuable for a fertilizer, calculating their 

 value on the basis of valuations used in Alabama for commercial fer- 

 tilizers. (3) The vines lose a large percentage of their nitrogen when 

 left on the ground during the fall and winter months." 



Fertilizer analyses, K. T. Lupton, LL. D. (pp. 10-40). — This 

 contains tables of analyses of one hundred and seventy-nine commer- 

 cial and other fertilizers, including phosphates, bone dust, muriate of 

 potash, kainit, ammonium sulphate, tankage, bat manure, cottonseed- 

 hull ashes, cotton-seed meal, and green sand; guaranteed composition 

 of commercial fertilizers licensed ; list of licenses for season of 1889-90, 

 and the fertilizer laws of Alabama. 



