May 14,1917 
Soil Nitrogen and Nutrition of Citrus Plants 
219 
At a depth of 18 to 30 inches the nitrate content was very low in all cases, 
the maximum amount found being only 0.32 mgm. 
The nitrate content of the surface 6 inches in plot 3? as shown in figure 
6 amounted to only 1.2 mgm. at the time of the first irrigation. During 
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Fig. 5.—Diagram showing the distribution of nitrates in plot C before and after irrigations. Season of 1916, 
the time intervening between the first and second irrigation the nitric 
nitrogen increased to 2.48 mgm., after which the amount remained fairly 
constant for the remainder of the season. The increase between the first 
