RANGE PRESERVATION AND EROSION CONTROL. 
19 
tamped firmly in cans 14 inches wide and 17 inches high. Six large 
test pots were used, three of which contained eroded and three non- 
eroded soil, and each was planted to five seedling plants as follow-: 
One set, consisting of one pot of eroded and one of noneroded soil, 
to a pedigreed field pea known as Kaiser variety; one set to native 
bromegrass, locally called wild oats (Bromus marginatum semi- 
nudus) ; and the third set to a pedigreed wheat known as Kubanka 
No. 1110. 
The pots were hermetically sealed and so arranged that all the 
water loss from the soil had to pass through the plants in the form 
of transpiration or evaporation. The pots were weighed at regular 
intervals and water was added to the soil so that the moisture content 
was kept practically constant. Throughout the experiment the aver- 
age moisture content was about 30 per cent, a supply ample to pro- 
duce the most vigorous growth on both soil types. 
Owing to the action of the elements on the two soils studied there 
was an interesting and significant difference both in their chemical 
and physical properties. The percentages of salts important to the 
growth and development of plants in these soils are as follows : 
Table 7. — Salts important to the growth and development of plants on the two 
soils studied. 
Soil. 
Lime 
(CaO). 
Potash 
(K 2 0). 
Phos- 
phoric 
acid 
(P*0 5 ). 
Total 
nitro- 
gen. 
Loss on 
igniti n 
(humus). 
Eroded 
Percent. 
1.26 
1.49 
Per cent. 
1.53 
1.30 
Percent. 
0.22 
.33 
Per cent. 
0.156 
.488 
Per cent. 
6.64 
Noneroded 
14.65 
In all the constituents considered except potash, the noneroded 
soil is much the richer. The greatest difference is found in the total 
nitrogen content, one of the most important of plant foods. This is 
due to the fact that a large proportion of the nitrogen compounds 
are more or less soluble in water and consequently had been largely 
washed out of the eroded soil. 
The chief physical properties are those which affect the total water- 
holding capacity of the soils and the amount of water that can be 
absorbed from them by a plant. These properties are intimately as- 
sociated with the amount of organic matter in the soils. The eroded 
soil was found to have a maximum water-holding capacity of 46.8 
per cent as compared with 67.2 per cent in the case of the noneroded 
soil. At the same time the soil moisture which can not be absorbed 
by the root hairs of the plant, and which is therefore termed " non- 
available" water, was found to be 15.6 per cent in the eroded soil 
and 19.3 per cent in the noneroded soil. Owing to this the combi- 
