26 
Colorado Experiment Station. 
There Was Some Difficulty With Sand. 
The total ash is high compared with the average, but when the 
sand and silicic acid are subtracted, the results are very close to those 
of the standard analysis. One of the difficulties with a few of the 
older samples of the cow manures was the presence of large amounts 
of sand and gravel which had been blown or trampled into them. Lit¬ 
erally a quart or two of gravel had to be picked out of some of the 
samples before anything in an analytical way could be done with them. 
For this reason the sand and silicic acid were carefully determined in 
the ash, although some of the silicic acid belongs to the ash of the 
manure as it was a constituent of the plants the animals fed upon. 
The Soluble Portion is Nearly a Constant Quantity. 
While discussing the soluble and insoluble ash in sheep manure, it 
was stated that the soluble ash did not increase with age, but remained 
near 7 percent. This is also the case with the cow manures, except 
that the soluble ash amounts to about 5 percent. This probably points 
to the fact that the manure can retain about that amount of soluble ash, 
the rest being lost through leaching. We know from many experi¬ 
ments, some of which have already been cited in connection with the 
discussion of sheep manure, that all manures lose rapidly in bulk and 
weight when exposed to the weather, and an increase in the ash con¬ 
tent, soluble as well as insoluble, should take place, but we find that 
the soluble ash remains constant. The loss consists chiefly of soluble 
salts and liberated gases, such as carbon dioxide and nitrogen, caused 
by the action of micro-organisms. From the results given in Table IV, 
it would seem that almost the whole of these soluble salts are lost 
since the manure retains only about 5 percent no matter how old it is. 
This loss is principally due to leaching, for some of our rainfalls are 
heavy, and sometimes extend over a considerable period. 
Solubility of the Nitrogen, Potash and Phosphoric Acid in Water. 
It was so unusual to find the potash retained by the manure to a 
greater extent than the nitrogen, that 200 grams of manure No. 17 
were extracted with water, and the potash and phosphoric acid de¬ 
termined in the extract. 
After washing with water there remained 164.4 grams of manure 
making a loss in the extract of 17.8 percent. The nitrogen was de¬ 
termined in the residue and in the original sample, the former giving 
1.817 percent and the latter 1.125 percent, a difference of 0.692 per¬ 
cent, which was the amount soluble in water. The phosphoric 
acid in the soluble portion amounted to 0.265 Percent and the potash 
to 1.700 percent calculated on the air-dry manure. This shows con¬ 
clusively that it was not because the potash was held as some insoluble 
