28 BULLETIN 218, U. S. DEPARTMENT OF AGRICULTURE. 



production is taken into consideration, as in the last part of Table 

 XII, it is shown that the average increase in production due to sum- 

 mer tillage has not been sufficient to pay for its increased cost as 

 compared with several other methods. It shows a loss of $3.03 per 

 acre. Disked corn ground with its smaller yield shows an average 

 profit of 87 cents per acre. Spring and fall plowing with about the 

 same yields as disked corn ground have just about paid expenses. 

 The use of green manure, with a high production cost and an average 

 yield of only 22 bushels per acre, has resulted in an average loss of 

 $7.76 per acre. 



AKRON FIELD STATION, COLO. 



The soil of the field-station farm at Akron, Colo., is of a clay-loam 

 type, locally known as "tight land." It is characterized in the 

 native vegetation by a growth of short grass. As it carries in each 

 unit section a considerable supply of water, and as it offers no phys- 

 ical resistance to the development of roots, it is possible to store in 

 it a large quantity of water available to a crop. It is a soil on which 

 maximum results would be expected by practicing methods of tillage 

 calculated to store water. 



Of the six years offered for study from this station, two years have 

 been productive of good crops of oats, two of light crops, and two 

 of poor. They do not show in their average a very wide range 

 in yields as a result of different cultural or cropping practices. The 

 heaviest yields have followed summer tillage, which has given an 

 average for the six years of 28.7 bushels per acre. The next highest 

 yield, 25.3 bushels per acre, has been from spring-plowed corn 

 ground. This has been only 1 bushel per acre more in its yield than 

 spring-plowed wheat stubble. 



Green manuring has barely maintained yields as high as those 

 from land on which a crop of grain was harvested. 



Disked land shows a strong advantage in its yields of oats in favor 

 of corn as a preceding crop, as compared with the use of sorghum, 

 milo, and kafir as preceding crops. 



The poorest yields of oats have been obtained following alfalfa 

 and brome-grass sods and on disked sorghum land. 



Oats following wheat have been better by both spring and fall 

 plowing than oats following oats. 



The relative merits of fall and spring plowing appear to be depend- 

 ent on the season, but the average of the seasons under study is 

 slightly in favor of spring plowing. 



Subsoiling, when compared with plowing at the same time without 

 subsoiling, has been done at the expense of sharp reductions in yield. 



Furrowing with a lister and leaving the ground rough through the 

 winter has produced slightly greater average yields than plowing 

 similar stubble either in the fall or spring. 



