TILLAGE AND ROTATION EXPERIMENTS AT NEPHI, UTAH. 
The facts thus brought out seem to indicate that at Nephi stubble 
land allows the winter precipitation to penetrate to greater depths 
than fall-plowed land and that the loose surface of the fall-plowed 
land retains more of the precipitation of winter than the compact 
surface of the stubble land. They indicate, further, that when the 
stubble land is plowed in the spring it loses much of the moisture in 
the surface foot, as does also the fall-plowed land when it is replowed 
or double disked, one of these operations always being necessary in 
the spring on fall-plowed land. This is decidedly to the disadvantage 
22 
SP/P/A/G PLOIA//A/G 
FALL PLOW/A/G 
4 S- 6 / 
OETPr/J //V 
Fig. 3.— Graphs showing the average seasonal decline in percentage of moisture in each of the upper 
6 feet of soil, as found in the spring-plowing and fall-plowing tests at the Nephi substation, 1909 to 
1912, inclusive. 
of the fall-plowed land, which during the winter retains so much 
moisture in the surface foot. Lastly, the facts brought out' show 
that the moisture content of the soil below the surface foot was prac- 
tically constant throughout the season. This was favorable to the 
spring-plowed land, which had allowed the moisture to penetrate 
into the third, fourth, and fifth feet. That winter wheat makes use 
of moisture found at these depths is evidenced by the fact that in 
1910 the roots of a winter- wheat plant growing on the station were 
found to extend more than 7 feet below the surface of the ground. As 
the spring-plowed plats had some advantage in soil-moisture content 
below the second foot, the higher yields on these plats were anticipated. 
63648°— Bull. 157—15 2 
