ii: 



Journal of Agricultural Research 



Vol. X. No. 3 



with a gradual decrease in this difference toward the surface. Below 

 7 feet, however, the cropped plots show a larger content than the fallow 

 ones. The larger difference in moisture content between cropped and 

 fallow plots in the upper layers of soil is readily explained by the fact 

 that the crop draws most water from that zone. The action of the crop 

 in lowering the moisture content of the soil is quite distinct although 

 rather peculiar. 



The lowest moisture content is found in the cropped plots in the fifth 

 and sixth feet, with an increase below and above that depth. In the 



Percenfaqe of moisture 



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FaUouu S Cropped 



Fig. I. — Diagram showing the effect of cropping and fallowing under irrigation on the distribution of soil 

 moisture in the fall to a depth of lo feet. Average of three years. 



fallow, on the other hand, it is in the sixth and seventh feet that the 



largest moisture content is found, a rapid decrease taking place below 



that depth. 



Under Dry-Farming 



This test was carried out at the Nephi Substation between the years 

 1908 and 1 91 2, inclusive. Cropped plots which were devoted to a 

 rotation including com, peas, potatoes, and wheat are here compared 

 with fallow plots rotated with wheat. Except for the wheat, all plots 

 were cultivated, so that the cropped plots are strictly comparable with 

 the fallow ones. 



The plots were sampled in duplicate in the spring about May 2 1 , in 

 the summer about June 16 and July 21, and in the fall about the first 

 week in October. 



