60 
IOWA ACADEMY OF SCIENCES. 
TABLE I. 
SOILS. 
No. 3. Continuously unmanured— 
1st 9 inches 
3d 9 inches 
No. 10 A. Ammonium Salts only— 
1st 9 inches 
3d 9 inches 
No 5 A. Mixed mineral manures without nitrogen— 
1st 9 inches. 
3d 9 inches 
No. 7 A. Mixed minerals and ammonium salts — 
1st 9 inches 
2d 9 inches 
Potash solu- 
ble in dilute 
acetic acid 
Phosphoric 
acid soluble 
in dilute ni- 
tric acid. 
Percent. 
Percent, 
.015 
.0T5 
.018 
.047 
.013 
.076 
.019 
.047 
.038 
.108 
.023 
.058 
.039 
.136 * 
.018 
061 
No 2 Farm j^ard manure— 
1st 9 inches 
3d 9 inches 
.011 .0,93 
.026 .065 
These results are striking, especially those for potash solu- 
ble in dilute acetic acid. The surface soils that had annually 
received supplies of available potash (in the mineral and barn- 
yard manures) showed two to three times as much potash solu- 
ble in acetic acid as did the soils not thus reinforced ; while the 
subsoils showed much smaller differences. Unfortunately the 
amounts soluble in strong HCl were not reported in the abstract 
to which I have access, if determined at all. 
In 1881, Deherain*'^ observed that in the neighborhood of 
Grignon, France, where phosphatic manures had but little or no 
effect, the soil contained no more than an average amount of 
phosphoric acid, and yet gave up to acetic acid from one-fourth 
to one-half of the total amount present. Later, having followed 
up his studies in the use of acetic acid as a means of distin- 
guishing between assimilable and non- assimilable phosphates, 
he finds that ' ‘while the plots manured with phosphatic manures 
yield appreciable quantities of phosphoric acid to the action of 
acetic acid, the phosphate-exha asted soils yield only insignifi- 
cant quantities. ” These last would, of course, have yielded very 
considerable quantities to strong hydrochloric acid, by the usual 
mode of analysis. 
In 1882, A. Vogelf suggested that if a sample of soil tested 
with acetic acid yields no indications of phosphoric acid, its 
^Quoted iu Jour. Oliem. Soc., London, 1894, p. 119. 
4Loc. cit. quoted from Bied. Oentr., p. 852. 18^3. 
