EXPERIMENTS IX SUBSOILING AT SAX ANTONIO. 



11 



EFFECT OF SUBSOILING ON CROP YIELDS. 

 Tabic II shows the effects of subsoiling on the yields of corn, cot- 

 ton, and oats. 



Table II. — Average yield of crops in rotations subsoiled and rotations not sub- 

 soiled at the San Antonio Experiment Farm, WW to 191.2, inclusive. 



Summary of Averages. 



Crop. 



Corn bushels. . 



Cotton pounds.. 



Oats, grain bushels. . 



Oats, hay pounds. . 



A verage 



Yield per acre. 



Not sub- 

 soiled. 



20.2 

 549. 4 

 11.5 

 3,557 



Sub- 

 soiled. 



18.7 



521.9 



11.7 



3,121 



Gain(+) 



or 

 loss (— ). 



- 1.5 



- 27.5 

 + .2 

 -430 



Yield expressed in percent- 

 ages of untreated plats. 



Not sub- 

 soiled. 



100 

 100 

 100 

 100 



100 



Sub- 

 soiled. 



92.6 

 95 



101.7 

 87.7 



94. 25 



Gain(-f) 



or 

 loss (— ). 



-7.4 

 - 5 

 + 1-7 

 -12.3 



From the foregoing table it is seen that in four rotations snl (soil- 

 ing has decreased the yields of corn and in one rotation it has 

 slightly increased the yield. The cotton yields have been increased 

 in two rotations and decreased in three rotations. In those portions 

 of the table showing the average yield by years it is seen that subsoil- 

 ing gave decreased average }delds of corn and cotton in each of the 

 three years. The summary shows that when the three-year average 

 for all crops concerned is taken into consideration, subsoiling has 

 decreased the yield of all crops except oats for grain. Since the tests 

 with oats have not been so extensive as with other crops, it is doubt- 

 ful whether this result can be taken as conclusive. 

 [Cir. 114] 



