Tjie IjULLETIN. 7 



in the mature plant (dry) as follows: leaves, .42 ])er cent; seed, 

 1.34 per cent; lint, .GG per cent; and stem, roots, etc., combined, 

 l.SG per cent. Hence, it is seen that the seed are well stored with 

 potash, as well as phosphoric acid, but the stems, roots, etc., are the 

 parts containing the highest per cent of this constituent. 



Nitrogen. 



As is the case with phosphoric acid and potash, the percentage of 

 nitrogen contained in the various parts of the cotton plant is influ- 

 enced, within rather narrow limits, by the quantity and proportion 

 in which the fertilizing constituents are combined in the fertilizer 

 used. The highest per cent of nitrogen in the leaves and other 

 vegetative parts was found in plants which were produced on un- 

 fertilized land, while its lowest per cent was present in the seed and 

 stems, bolls, roots, etc., of plants receiving the fertilization indicated 

 in Table I by NPK. Fertilization high in nitrogen and potash 

 seemed to stimulate an increase of the nitrogen-content of the seed. 

 The seed and leaves are very rich in this clement, and especially so are 

 the seed. The average nitrogen-content of the different parts of the 

 cotton plant, analyses reported on dry sample, was found to be 1.46 

 per cent in the leaves; 2.98 per cent in the seed; .30 per cent 

 in the lint; and .65 per cent in stems, roots, etc., combined. It 

 might be noted in passing that the plat receiving the highest ap- 

 plication of nitrogen, with normal quantities of phosphoric acid and 

 potash and represented ISTgPK, was the one from which the seed 

 and lint of the cotton draw most heavily, in pounds per acre, upon 

 the plant-food constituents of the soil. In other words, the plants, 

 as the result of this heavy application of nitrogen, not only took 

 up more nitrogen from the soil per acre in the seed and lint, but 

 were enabled, directly or indirectly, thereby to remove more of 

 the other fertilizing constituents than were removed as the result 

 of any of the other fertilizer applications used. The explanation 

 for this latter effect, resulting from a heavy application of nitrogen 

 in the form of cotton-seed meal, would seem to lie either in increased 

 solubility of the fertilizing constituents present in the soil through 

 the action of weak organic acids formed by the decomposing meal, or 

 in a strengthening of the attacking power of the root system as a 

 result of the promotion of a heavier growth of all parts of the 

 plant, accompanied by increased demands for these inorganic con- 

 stituents by the plant organism, or to a combination of both. 



