Feb. 26,1917 
Effect of Water and Manure on Nitrates in Soils 
353 
While the percentage moisture, total salts, and nitrates all decrease 
in the cropped soil receiving 5 tons of manure as compared with that 
receiving none, the total salts show a much greater proportional lessening 
Fig. 14.—Graph stowing effect of irrigation water on nitrates, total soluble salts, and percentage of mois¬ 
ture in fallow soil in the fall. Average for all manuring treatments during three years to a depth of io 
feet. 
with no irrigation and an application of 5 inches of‘water than does that 
of the nitrates at the same treatments, while the moisture percentage 
decreases because of the manure, about the same amount for each 
Fig. 15.—Graph showing effect of manure on nitrates, total soluble salts, and percentage of moisture 
cropped and fallow soil at the close of the cropping season. Average for all moisture treatments during 
three years to a depth of io feet. 
irrigation treatment. These differences, while quite evenly distributed 
in depth for the total salts and nitrates, are greater at the fifth, sixth, 
and seventh feet for the percentage of moisture. 
