TILLAGE AND ROTATION EXPERIMENTS AT NEPHI, UTAH. 



9 



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 



SPP/A/G PLOLV/A/G 



FALL. PLOW/A/G 



2 3 4 & 6 / 2 3 

 OE-PT/J /A/ pl^bt. 



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 



