191'J] AGRICIfLTURAL CHEMISTRY — AGBOXECHNY. 503 



"Ash constituents fall Into t\\<> groups: fit Those present In quantities that 

 show relatively little variation whatever be the chemicals added to the soil — 

 lime, magnesia, phosphorus pentoxid, sulphur trloxid, manganous oxld, alumina, 

 and ferric oxld; and (2) those which show great fluctuations in the quantity 

 present — silica, potash, and soda. In the iir>t group the plants Beemed t«> be 

 able to get the required quantity of constituents mentioned from the boII <»f all 

 plats studied whatever was offered in excess, and reached an equilibrium that 

 was little affected hy the varying conditions, in the second group wide varia- 

 tions OCCUr, sometimes With an increase of the ions offered in excess, as in 

 sodium Chlorld and sodium nitrate, somel imes hy the absorption Of something 

 else, as increase in silica in plats receiving calcium carbonate and acid phi 



pliate. 



" Bfanganous oxld is the only constituent regularly present In greater propor- 

 tion in the roots than in the tops. 



" In some cases the high absorption of one constituent is accompanied by the 

 low absorption of another, and vice versa. Such reciprocal pairs are silica and 

 potash, soda and lime, and potash and magnesia. The silica-potash ratio is 

 relatively steady. When silica equals 1, potash varies between 1.16 and 2.18 in 

 the tops and between 1.33 and 2.32 in the roots, except when the substance 

 added to the soil is high in calcium, when the value of potash becomes less 

 than unity in both tops and roots. 



"The soda-potash ratio is much more variable, being always more than 1 in 

 both lops and roots. When mixtures of sails are added to the soil, potash rises 

 to very high relative values. 



"There is a suggestion that sodium may perform some functions also per- 

 formed hy potassium, indicating the possibility that sodium might in part re- 

 place potassium in fertilizers. 



"The calcium-magnesium ratio in spinach, both in leaves and in roots, is 

 exceptional in having a value greater than unity. The only exception is seen 

 in the tops of plaids receiving a heavy treatment with calcium carbonate. 

 This fact seems to suggest the practical importance of magnesium salts as fer- 

 tilizers for spinach." 



Bacteriological studies on alfalfa silage, O. W. IIuntkk (lour. Agr. Re- 

 search [U. S.], 15 (1918), No. 11. p\). 571-692, figs. 3).— This is a report of 

 bacteriological studies made in connection with the Investigations at the Kansas 

 Experiment Station on alfalfa silage (E. S. R., 37, p. 709). Three series of 

 studies were made, the first two on samples of the silage obtained under aseptic 

 conditions from the experimental silage of 1914 and 191"), previously described 

 ( E. S. R., 37, p. 671), and the third on green and cured alfalfa stored in sterile 

 milk bottles with and without carbohydrates. Chemical analyses were also 

 made of the bottled silage in order to determine the effect of carbohydrates on 

 the quality of the Bilage. 



The results obtained from the first two studies Indicate that alfalfa when 

 siloed alone undergoes a typical silage fermentation which is caused by micro- 

 bial flora, and is practically identical with that obtained from silau'e made from 

 the common forage crops. The final product is of very poor quality. When a 

 fermentable carbohydrate is added to the alfalfa at the time of siloing, a good 

 quality of silage is produced, although but little difference can be noted between 

 the microbial flora of such silage and that of silage .made from alfalfa alone. 



Similar results were obtained in the third series of experiments. The chem- 

 ical data Indicate that silage produced from alfalfa with a carbohydrate sup- 

 plement has a higher acid content than the alfalfa alone. More amino nitrogen 

 and more ammonia were formed in the alfalfa silage than in th<e alfalfa and 



