20 
BULLETIN 675, TJ. S. DEPARTMENT OF AGRICULTURE.' 
nation of higher water-holding capacity and higher percentage of 
available water when the soils are saturated there remains for the 
plant 16.7 23er cent more water in the noneroded than in the eroded 
soil. 
Tables 8 and 9 and figures 4 and 5 summarize the results as to vege- 
tative growth and the water requirements of field peas, native brome- 
grass, and cultivated wheat grown- in the two soils. In the case of 
each of the three plants the table shows that a much greater amount 
of water was required for the production of a unit of dry matter in 
eroded than in noneroded soil. 
Table 8. — Pounds of irate' required by peas, bromegrass, wheat, and wheat 
heads per pound of dry matter produced. 
Soil, 
Peas. 
Brome 
grass. 
Wheat. 
Wheat 
heads. 
Eroded 
841 
467 
1,339 
1,110 
472 
343 
1,370 
407 
Noneroded 
80.3 
20.6 
37.6 2.66. 
Table 9. — Summary of vegetative growth and water 
bromegrass, and wheat . 
requirements of peas, 
Plant and soil. 
Peas: 
Eroded soil 
Noneroded 'soil 
Native bromegrass; 
Eroded soil 
Noneroded soil 
Wheat: 
Eroded soil 
Noneroded soil 
Water 
used per 
pound 
dry mat- 
ter pro- 
duced. 
i In the case of peas the length of stem is given instead of the leaf length. 
Figure 5, summarizing the vegetative growth and water require- 
ment of peas on the eroded and noneroded soil, shows a remarkable 
contrast in the vegetative growth and other activities. The number 
of leaves is as 1 to 2.7 ; the leaf length, 1 to 3.3 ; the total dry weight 
produced, 1 to 8.3 ; and the water used per plant, 1 to 4.6, all in favor 
of the noneroded soil. In the water requirement per unit of dry 
matter, on the other hand, the ratio is reversed, being as 1.8 to 1 on 
the eroded and noneroded soils, respectively. Hence there are a great 
many more leaves, greater stem and leaf length, and more dry mat- 
ter produced on the noneroded than on the eroded soil, with a notably 
smaller amount of water (PL IV). The latter fact, of course, is ac- 
