Feb.26,1917 Effect of Water and Manure on Nitrates in Soils 339 
nitrates found in the soil after the crop had been harvested, and the 
total yield of grain and straw. The moisture treatments in the illus¬ 
tration have been so arranged that the amount of water in the soil 
decreases from left to right. 
The total salts do not seem to vary consistently with any of the other 
determinations shown. In general, however, the nitrates vary inversely 
as the percent 
SM 
o 
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5 " W. 
5 " W. 
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10" w. 
20" W. 
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30“ W. 
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40' W. 
40 " w. 
age soil moisture 
and the crop 
yield, the crop 
yields standing 
somewhat in 
proport ion 
to the total 
amount of water 
for the season 
in the tanks. The variations are thought 
to be due largely to changes in soil- 
moisture content at the different stages. 
FIELD EXPERIMENTS 
The field experiments were carried 
on at the Greenville Experimental Farm, 
2 miles north of the Utah Agricultural 
College, at Logan, Utah. The soil is of 
a sedimentary nature, being derived 
from the mountains near by, which con¬ 
sist largely of limestone, quartzite, and 
dolomite. In physical nature the soil is 
mostly fine sand, silt, and clay, with 
remarkable uniformity to at least 10 feet, 
the depth to which the samples were 
taken. The soil contains about 43 per 
cent of calcium and magnesium car- 
.</» 
o\ 
JAW 
No 
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W 
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w. 
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20 " 
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W. 
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40 “ 
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S u w. 
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Fallot 
NO W* 
Fig. 4.—Arrangement and treatment of plots 
in field experiment. 
bonates and is rich in all the essential plant-food elements with the 
exception of nitrogen. The plots had received no manure for many 
years before the experiment was begun. A more detailed description of 
the soil and conditions of the farm have been published by the Utah 
Station. 1 
Figure 4 shows the arrangement of the plots and the treatments 
received. There were 12 cropped and 18 fallow plots unmanured, 12 
cropped and 12 fallow manured at the rate of 5 tons, and 12 cropped 
and 12 fallow manured at the rate of 15 tons to the acre. 
1 Widtsoe, J. A., and McLaughlin, W. W. The movement of water in irrigated soils. Utah Agr. Exp. 
Sta. Bui. 115, p. 197-268, illus. 1912. 
