112 



THIRD ANNUAL SESSIONS 



operation. Prof. Chilcott, the chief of this office, explained the nature 

 of the work at the first meeting of this association held at Denver. 



Comparative Results. 



"Durum wheat, on spring plowed wheat stubble, yielded at the rate 

 of 22.7 bushels per acre; on fall plowed wheat stubble, 27.3, and on sum- 

 mer tilled wheat stubble, 40.5. Common six-rowed barley, on spring 

 plowed barley land, yielded at the rate of 19.6 bushels per acre; on fall 

 plowed barley land, 43.3 bushels per acre; and on summer tilled barley 

 land, 67.7. Kherson oats, on spring plowed oat land, yielded at the rate 

 of 34.4 bushels per acre; on fall plowed oat land, 68.5; and on summer 

 tilled oat stubble, 82.3 bushels per acre. The plats giving these returns, 

 lie side by side on a uniform soil. 



Soil Treatment. 



"The seeding was done on all at the same time and at the same rate. 

 The difference in the yields can be accounted for only by the different 

 methods of tilling the land. We do not presume that fall plowing will 

 always yield so much more than either of the other methods, as it did 

 this spring, but we offer these figures to show what a wonderful differ- 

 ence in yield may result from tillage. These are some of the results as 

 represented by yields from summer tillage on the Sub-Station farm. 



IVIoisture Tests. 



"During the two past seasons, considerable attention has been given 

 to the study of soil moisture. The results to date, indicate that the North 

 Platte soil will retain only about 16 per cent, of water, reckoned in pro- 

 portion to the dry weight of the soil. The winter crops as wheat and oats, 

 will take out of the soil about seven per cent, of the moisture, or reduce 

 the moisture in the soil to abount nine per cent., before the plants suffer 

 di/outh. It also seemis appiarent that such crops as the above, have use 

 of the water in the surface six feet of the soil. In round numbers, one 

 per cent, of moisture in a six foot column of the North Platte soil is 

 equivalent to one inch of water. 



Summer Fallow. 



"Therefore, it seems evident that we can store by summer tillage, 

 seven inches of water that may be available for the succeeding crop. 

 This amount of water distributed as it is throughout the soil, is worth 

 very much more — probably fully twice as much — as the same amount of 

 rainfall. 



Depth of Moisture. 



"Another noticeable feature is that the moisture content of the soil 

 is influenced to a depth of ten feet, possibly farther, by summer tillage. 

 Whether the water driven to this depth, later becomes available for the 

 use of the plant is not known. It is quite probable that the increase in 

 yields from summer tillage, comes largely because of this deep reservoir 

 of water, which is drawn on during the periods of drouth. The amount 



