DETAILED STUDY OF SOIL TYPICAL OF EXTENSIVE AREAS. 25 
TaBLE II].— Number of bacteria per gram of soil and nitrifying power of samples from 
plats 10, 20, 30, 40, 180, 190, 290,' 240, 260, and 270, Truckee-Carson Experiment 
Farm. 
Gi ; NiyIne 
7 umber o power o 
No. of Been of bacteria per | soils (parts | Character of soil. 
plat. ae gram. per mil- | 
lion). | 
es Pere ee ee S| er |e |e nes 
Inches 
10 0-6 435, 000 4.4 Very poor. 
6-12 251, 000 2.0 
12-18 26, 650 .0 
18-24 146, 250 3.0 
| 24-36 1,000 .0 
20 0-6 19, 500 54, 2 Very productive. | 
6-12 11, 250 6.8 Good growth of | 
12-18 30, 000 1.0 alfalfa. | 
18-24 4,500 .0 
24-36 3, 000 .0 | 
30 0-6 160, 000 3.0 Poor and com- | 
6-12 65, 000 .0 pact. 
12-18 262, 000 .0 
18-24 19, 855 .0 
24-36 10, 000 20 
40 0-6 210, 000 20. 4 Productive. 
6-12 20, 000 4.0 Good growth of 
12-18 135, 000 1.0 alfalfa. 
18-24 45, 000 0 
24-36 1, 000 30 
180 0-6 60, 000 4.72 | Very poor. 
6-12 175, 000 1.54 | Alkali high. 
12-18 180, 000 4.32 (See fig. 6.) 
18-24 4, 000 2.54 
190 0-6 -3, 600 36.30 | Productive. 
6-12 168, 000 37. 45 
12-18 1,554, 000 12.75 
18-24 704, 000 12. 25 
290 1 0-6 273, 000 30.00 | Productive. 
6-12 396, 000 20.00 | Old alfalfa field. 
12-18 262, 500 14. 60 (See fig. 13.) 
18=24 327, 000 4.00 
240 0-6 52, 000 69.00 | Fallow. (See 
6-12 78, 700 4.50 fig. 11.) 
12-18 56, 000 . 40 
260 0-6 81,000 18.00 | Fallow. (See 
6-12 153, 300 40. 00 fig. 12.) 
. 270 0-6 72, 000 100. 00 
6-12 2,790, 000 92. 30 
} 
1 Plat 290 is located in an old alfalfa field one-fourth mile north of Fallon. 
DETAILED STUDY OF SOIL TYPICAL OF EXTENSIVE AREAS. 
Plats 300 to 350 are representative of a somewhat extensive type 
of soil of the Truckee-Carson project. This soil is very unproductive 
as a rule, almost barren in many cases, yet all through it, wherever 
properly leveled and irrigated, are spots of a few square rods in area 
that are normal and productive. The difference between these two 
conditions seemingly can not be explained by any of the now known 
causes of infertility. There is a certain difference in texture, or rather 
in the physical properties; the productive soil is loose and sandy, 
while the unproductive type, although sandy, contains a small quan- 
tity of clay which when shaken up with water remains suspended 
indefinitely and the soil cements on drying. These physical differ- 
ences, while no doubt factors, do not seem adequate causes of the 
extremely low fertility. The total alkali content is not high enough 
211 
