18 



SOILS OF THE TRUCKEE-CARSON IRRIGATION PROJECT. 



and sulphates, as well as the curve showino; nitrification, should be so 

 erratic and variable. 



Figure 13 shows the nitrifying power of samples from plats 280 and 



1200 



■100 



-200 



Fig. 11.— Diagram showing the nitrification of ammonium sulphate in samples of soil from different deptha 

 from plats 240 and 2.")0, Truckee-Carson Experiment Farm. Original nitrate present in samples from 

 plat 240: Depth, to inches, (i.8 parts per million; r, to 12 inches, 8; 12 to 18 inches, 10.4; IS to 24 inches, 

 C; 24 to 30 inches, 5. From plat 250: Depth, to 6 inches, 28 parts per million; 6 to 12 inches, 48; 12 to 

 18 inches, fi; IS to 24 inches, 5.2; 24 to 30 inches, 7. 



290, located in an old alfalfa field just north of Fallon. These soils 

 are very productive, and it was expected that they would show 

 a greater nitrifying ]M)wer than they did. This may possibly be 



211 



