16 



SOILS OF THE TEUCKEE-CARSON IRRIGATION PROJECT. 



held together by some cementing material. As shown in figure 6, the 

 nitrifying power of samples from plat 180 is almost nothing. In this 

 figure the chlorid and sulphate curves are of interest, as those of plat 

 180, the poor soil, are far above those of plat 190, the good soil.^ 



Fig. 7.— Diagram showing the nitrification of ammonium sulphate in samples of soil from different depths 

 from plat 200, Truckee-Carson Experiment Farm. Original nitrate present in samples: Depth, to 6 

 inches, 7.68 parts per million; 6 to 12 inches, 5.8; 12 to 18 inches, 3.93; 18 to 24 inches, 4.32; 24 to 36 inches, 

 1.82. 



Figures 7 to 10, inclusive, show the nitrifying power of samples of soil 

 from plats 200, 210, 220, and 230. They are in fields which have only 

 recently been leveled and irrigated; in fact, 1909 was the first year 

 they had been cropped. They produced a fair crop of barley, but the 



II 



^*^ in 



0£Pr/y /IT lA/MC^ S/JPfPl£S l^£/?£ Z4/(£/^ 



.:l'roe>' e'rria" la'^ie" i8"7d24" 24^36" 



r.^ates-_P[^^l2. 



200^ 



100 §1^ 

 -100 11^ 



Fig. 8.— Diagram .sliowing Ihe nilrification (.fuinmoniiun sulphate in samples of soil from dillerent depths 

 from plat 210, Tnukee-Carsou KxperinioiU Farm. Original nitrate present in samples: Depth, to (1 

 inches, 2.06 parts per million; (i to 12 inche.s, 4.8; 12 to IS inches, 4.1(1; 18 to 24 inches, 3; 24 to 3C. inches, 2. 



young alfalfa sown in the barley was doing only fairly well. The 

 curves from all of these plats show a very low nitrifying jjower, yet a 

 glance at the figures shows that nitrates were ])resent in moderate 

 quantities in the original samples. 



' Uridge readiugs ou these samples were made by Mr. Jensen. 



211 



