16 



BULLETIN 157, U. S. DEPARTMENT OF AGRICULTURE. 



would have been obtained. With the data available, however, the 

 question seems to be not so much how deep to plow as how well to 



plow. 



Depth op Fall and Spring Plowing. 



As already stated, there is always need in the spring of replowing 

 or double disking land that has been plowed the previous fall. Be- 

 cause of this condition, an experiment was commenced in 1911 to 

 determine whether it is best to plow deep in the fall and then shallow 

 in the spring, or vice versa. In this test, plats 24C and 25C have 

 been used alternately with plats 25A and 26A. One plat was plowed 



V7ELD /A/ SUS/VELS PER AC/?E 

 O 2 4- 6 8 /O /2 /? /6 /3 20 22 



/3.Q V/////////////////////////////////>//A 



/3.0l 



/20\ 



Fig. 8.— Diagram comparing the annual and average yields obtained in the fall depth-of-plowing 

 tests at the Nephi substation, 1910 to 1913, inclusive. 



only 3 inches deep in the fall, while the other was plowed 8 inches 

 deep at the same time. The following spring the plat which was 

 fall plowed 3 inches deep was replowed 8 inches deep, while the other 

 plat was replowed only 3 inches deep. These plats were compared 

 with an adjacent plat treated according to general practice in the 

 region. 



The soil-moisture determinations made in 1912 show no difference 

 between the two methods. The yields of 1913, however, slightly 

 favor the plat plowed 8 inches deep in the fall and 3 inches deep in 

 the spring, but the difference is not significant. The test must be 

 continued for several years before the results will be of value. 



