SPEING WHEAT IN THE GEEAT PLAINS AEEA. 39 



account for an increase of more than 1 bushel per acre. At Judith 

 Basin the increase has been 1.9 bushels and at Scottsbluff 2.5 

 bushels. This evidence from eight stations, some of which have 

 records for study covering eight years, together with the evidence 

 at hand but not here reported of other work on depth of plowing, 

 which includes deep tilling and dynamiting, would seem to be con- 

 clusive that the nature of the Plains and the trend of their agriculture 

 are not to be changed by the simple expedient of working them to a 

 greater depth than is reached by the ordinary plow and equipment. 



Listing wheat stubble instead of plowing it in the fall has resulted 

 in a small increase of yield at seven of the eight stations where it has 

 been tried. At Amarillo it has increased the yields in the years of 

 heaviest wheat production, but it shows on the average a loss of 0.6 

 bushel per acre at this station. As it is a somewhat cheaper method 

 of preparation than fall plowing, it has consequently been a more 

 profitable one. 



Except at the Judith Basin and Akron stations, summer tillage 

 has given the highest average yields of any method under trial. At 

 Akron the yield on summer tillage has been exceeded by that on 

 spring-plowed corn ground by 0.3 bushel per acre. The reason for 

 the departure at the Judith Basin station from the general rule is 

 discussed under that station. For the whole 14 stations under 

 study the average increase in yield over disked corn ground has been 

 3.1 bushels per acre. Summer tillage requires the use of the land 

 two years to produce a crop and requires an extra amount of culti- 

 vation to keep it free from weeds in the fallow year. It consequently 

 has the highest acre cost of any method under trial except that of 

 green manuring. A study of the relative profits and losses from 

 different methods, as given in Table XIX, shows that the increase in 

 cost of production by summer tillage has been relatively greater 

 than the increase in yields resulting from it. With one or two 

 exceptions the highest yields have been obtained by this method. 

 It has not at any station been the most profitable when a profit was 

 realized nor has it been the source of the least loss where wheat has 

 been raised at a loss. At eight stations it shows a profit, but a smaller 

 one than was realized from some other method or methods. At 

 three other stations it has resulted in a loss while some other methods 

 have resulted in profit. At the remaining three stations its practice 

 has increased the loss attending the use of less expensive methods. 



Green manuring is the most expensive method under trial. It 

 resembles a fallow hi that it requires the use of the land for two years 

 for the production of one harvested crop, with the added expense of 

 seed and seeding. There is a saving in cultivation during the spring 

 while the crop is growing, but this is offset by the necessity of plowing 

 to turn the crop under and is not sufficient to make up for the cost 



