NITRIFYING POWEE OF SOILS AT DIFFERENT DEPTHS. 



17 



Figures 11 and 12 present the results obtained from samples of soil 

 from plats 240, 250, 260, and 270. The fields in which these plats are 



Fig. 9. — Diagram showing tlie nitrification of ammonium siilpiiate in samples of soil from different depths 

 from plat 220, Truekee-Carson Experiment Farm. Original nitrate present in samples: Depth, to 6 

 inches, 7.68 parts per million; (i to 12 inches, d. 91; 12 to 18 inches, 10; IS to 24 inches, 5. <i4; 24 to ;3G inches, 6. 



located have been merely leveled and left fallow, receiving regular 

 applications of irrigation water. The field containing plats 240 and 

 250 is never cultivated, while that containing plats 260 and 270 is 



I 

 I 



I 



I 



Nl 





40 



30 



20 



-10 



DEPTH /}T \^/H/CP S/JMP'LES tVEPE Ty^HEr/V. 

 ,0to6" 6'toI2" I2'^I8" I8%24' 24"ro36" 



Fig. 10. — Diagram showing the nitriCcation of animoniinn sulphate in samples of soil from different depths 

 from plat 2:'.0, Truckee-Carson Experiment Farm. Original nitrate present in samples: Depth, to 6 

 inches, 10 parts per million; (i to 12 inches, 8. Id; 12 tol8inches,5; IS to24inches,4..5t;; 24 to ;J0 inches, !).i'.. 



cultivated according to thorough summer-fallow methods. As the 

 conditions are abnormal it is not surprising that the curves of chlorids 

 78011°— Bui. 211—11 3 



