May 14,1917 
225 
Soil Nitrogen and Nutrition of Citrus Plants 
At the time of the first irrigation the nitrate content of the upper 6 
inches of soil Q amounted to 3.07 mgm. In this soil the maximum nitrate 
content of 17.81 mgm. was secured in the upper 6 inches after the third 
irrigation. The highest nitrate content at each depth was found at the 
point farthest from the furrows, while the lowest in each depth was 
/ST J/PO 4 ? 77 f /ST 
ao. or//?/?/&rr/o/v 
Fig. 12.—Diagram showing the distribution of nitrates in plot Q before and after irrigations. Season of 
1916. 
below the furrows. However, the minimum amount under the furrows 
was in no case less than 0,2 5 mgm., and the minimum amount 9 inches from 
the furrow was 0.56 mgm. Thus, it would seem that while the nitrate 
supply in this soil is somewhat uneven, there is no part of the soil which 
does not contain a considerable amount of available nitrogen (fig. 12). 
