Feb. 26,1917 Effect of Water and Manure on Nitrates in Soils 
355 
plots show the effects of the manure strongly, while with nitrates it is 
noticed most in the top feet. 
On the average, moisture, total salts, and nitrates are greater for a 
manuring of 15 than for 5 tons. This effect is more noticeable for the 
percentage of moisture with the larger irrigation applications and for 
the total salts and nitrates with the smaller ones. The nitrates are 
affected proportionately more by the manure applied than are the total 
salts or moisture content. For each of the determinations the top feet 
are influenced more than the lower ones by the larger application, when 
compared with the 5-ton manuring. 
When cropped plots are averaged for manure and depth the data 
show the moisture content to rise steadily with increasing quantities of 
irrigation water applied, while, in general, both total salts and nitrates 
decrease as the amount applied increases. In a comparison of the in¬ 
fluence of the irrigations, the nitrates show the greatest effect of the 
water. The ratio of total salts to nitrates as sodium nitrate rises from 
24.5 to 1 without water applied to 37.5 to 1 when 40 inches of irrigation 
water were used. 
For the fallow plots receiving no manure and 5 tons the moisture 
content of the soil was higher where the manure was not added, while 
both the total salts and the nitrates were higher with the manure when 
the irrigation applications were 10 and 5 inches, or more, respectively. 
The manure affects the nitrates proportionately more than it does either 
the total salts or percentage water. The nitrates are influenced propor¬ 
tionately more in the top feet than the other two factors discussed here. 
If the percentage of moisture in the soil where no water was applied 
be excepted, the moisture and nitrate content of the fallow plots re¬ 
ceiving 15 tons of manure were higher than for those on which no manure 
was applied, the differences being proportionately greater for the nitrates. 
The nitrates for these treatments showed the influence of the manure 
most when the irrigation was 5 inches, and where no water was added. 
The effect is a little more noticeable in the top feet than lower. The 
total salts were greater in every case where the soil was not manured 
than where it received 15 tons to the acre. 
The averages for nitrates and percentage of moisture are greater for 
the 15 than for the 5 tons of manure, although every irrigation treatment 
for nitrates does not show this tendency. Similar to the nitrates, the 
total salts increased more for the 15 tons of manure than with 5 tons 
only on the unirrigated and the 5-inch irrigated plots, but the average 
for the total salts favors the 5-ton application. The effect of manuring 
was especially noticeable for the total salts and nitrates in the upper 
feet, while with the percentage water the differences due to the manure 
were more evenly distributed for depth. 
The averages for the fallow plots show an increase in the moisture 
content and a decline in the nitrates for increasing applications of water, 
