6 



BULLETIN" 253, U. S. DEPARTMENT OE AGRICULTURE. 



Table IV presents the yields of corn from fall-plowed oat stubble 

 in two rotations, from spring-plowed oat stubble in one rotation, and 

 from both fall-plowed and spring-plowed wheat stubble in one rota- 

 tion each. 



Table IV. — Annual and average yields of corn from fall-plowed and spring-plowed 

 plats at the Akron Field Station, 1909 to 1914, inclusive. 





Rota- 

 tion 

 No. 



Yield per acre of grain (bushels). 



Treatment. 



1909 



1910 



1911 



1912 



1913 



1914 



Average. 



Fall plowed: 



1 

 3 



4 



26.4 

 25.7 

 23.1 



7.9 

 5.0 

 4.6 



9.3 

 9.2 



4.7 



29.1 

 34.3 

 34.3 



6.0 











16.7 



14.7 



7.6 



15.9 



Do 



14.8 





12.4 









25.1 



5.8 



7.7 



32.6 



2.0 



13.0 



14.4 





2 

 9 





Spring plowed: 



26.3 

 25.3 



7.6 

 12.4 



1.2 

 



33.7 

 37.5 



10.3 

 



17.4 

 12.6 



16.1 





14.6 









25.8 

 .7 



10.0 

 4.2 



.6 



-7.1 



35.6 

 3.0 



5.2 

 3.2 



15.0 

 2.0 



15.4 



Gain or loss of spring-plowed 





1.0 









Table V presents the yield of winter wheat from two continuously 

 cropped plats, the plowing of which was sometimes early and some- 

 times late. 



Table V. — Annual yields of winter wheat from, plats plowed at different dates at the 

 Akron Field Station, 1909 to 1914, inclusive. 





Plowing date and yield of grain (bushels). 



Plat. 



1909 



1910 



1911 



1912 



1913 



1914 





Plowed. 



Yield. 



Plowed. 



Yield. 



Plowed. 



Yield. 



Plowed. 



Yield. 



Plowed. 



Yield. 



Plowed. 



Yield. 



A 



B 



Sept. 14 

 Sept. 22 



14.5 

 12.9 



Sept. 18 



11.4 

 10.3 



Sept. 3 

 Aug. 12 



1.7 

 6.8 



Sept. 8 

 Aug. 15 



25.8 

 26.7 



Sept. 20 

 Sept. IS 



3.3 

 2.0 



Sept. 30 

 ..do.... 



24.5 

 24.8 



SOIL MOISTURE. 



Some of the factors determining the yields of small grain are 

 apparent to the casual observer. One of these is the greater number 

 of weeds growing with the grain crop on fall-plowed land at the 

 Akron Field Station. 



Another factor not so readily seen is the moisture content of the 

 soil at the time of seeding. A knowledge of the exact percentage of 

 moisture in the soil is not necessary. While the water-carrying 

 capacities of soils vary with their composition and compactness, it 

 may be taken as a working hypothesis that on the hard land of 

 eastern Colorado the relative depths to which water has penetrated 

 on different fields is a fair approximation of the relative amounts of 



