24 



SOILS OF THE TEUCKEE-CARSON lERIGATTON PROJECT. 



Table II.- 



-Denilrification in solution of samples of soil from plats 180. 190, 230, 260, 

 270, 280,^ and 290,^ Truckec- Carson Experiment Farm. 



' Plats 280 and 290 are located in an old alfalfa field one-fourth mile north of Fallon. 

 RELATIVE NUMBERS OF BACTERIA IN DIFFERENT SOILS. 



An estimation of the number of bacteria in a gram of soil that 

 woukl develop aerobically upon beef agar was made for many of the 

 sampling plats in accordance with the method jireviously described, 

 the results of which are shown in Table III. In accord with the 

 reports of other investigators, * the data presented in Table III 

 clearly show that the numbers of bacteria found in the different 

 samples bear no consistent relation to the fertility or crop-producing 

 power of the respective fields. 



No attempt was made to determine the relative numbers of proto- 

 zoa in samples of soil from the good and poor areas. If the develop- 

 ment of protozoa is determined by their food supply,- in other words, 

 by the numbers of ))acteria existing in the soil, it is obvious that in this 

 region the cro})-producing power can not be limited ^ by the abundance 

 of protozoa. 



' Lohnis, F. Ein Beitrag zur Methodik der bakteriologischen Bodenuntersiichung. 

 Central])latt fiir Bakteriulogie, ParawitenkuiKle und Infektioii.skrankheiteii, pt. 2, 

 vol. 12, no. 6-8, June 24, 1904, pp. 262-267. 



Chester, Frederick D. The Bacteriological Analysis of Soils. I'ldletin 65, Dela- 

 ware College Agricultural Experiment Station, March ], 1904. 



Voorhees, Edward B., and Lipinan, Jacob G. A Review of Investigations in Soil 

 Bacteriology. Bulletin 194, Office of Experiment Stations, U. S. Dept. of Agriculture, 

 October 26, 1907. 



- Russell, E. J., and Hutchinson, II. B. The Effect of Partial Sterilization of Soil 

 on the Production of Plant Food. Contributions from the Laboratory of the Rotham- 

 Bted Experimental Station, October, 1909, pp. 111-144. 



' Hall, A. D. The Fertility of the Soil. Science, n. s., vol. .'^2, no. 820, September 

 16, 1910, pp. 86:^-371. 

 211 



