6 BULLETIN" 214, U. S. DEPARTMENT OF AGRICULTURE. 



varietal tests, breeding, or seed selection makes available for general 

 use a better variety. The same seed is used on all plats at any one 

 station in any particular year. 



All seeding is done with a drill. Drill rows are spaced from 6 to 8 

 inches. As compared with more humid sections, light seeding is 

 practiced. The rate varies from 2 to 4 pecks, depending upon the 

 location and the consequent average climatic conditions. At Edgeley 

 N. Dak., where summer rains are more frequent and weeds more 

 troublesome, the seeding rate is 6 pecks per acre. Generally speaking, 

 the drier the condition the lighter the seeding. The seeding rate ? 

 date, and manner of seeding are the same for all plats at the same 

 station in any one year. 



For comparative study of the effect of environment and for securing 

 data on production certain of the work is made uniform at all stations. 

 This results in the attempted growth of spring wheat and other crops 

 in sections to which they are not adapted and in their growth at 

 certain stations by methods not adapted to the conditions obtaining 

 there. Such work, however, is limited, the most intensive studies at 

 each station being undertaken on the crops which are of greatest 

 promise in that locality. 



In the present study a table is presented for each station. The 

 first part of such table shows the yields that have been obtained in 

 each year by each of the different methods under which wheat has 

 been grown, considering only the treatment during the one year imme- 

 diately preceding the crop. The reasons for not differentiating the 

 study further have already been stated. 



Where more than one plat has been grown under the same treatment 

 for the previous year, only the average yield of the whole number 

 of plats so grown is given. Column 2 of the table shows the number 

 of plats so averaged. In the presentation of yields, the column 

 headed " Treatment and previous crop" indicates the method of 

 preparation, whether fall plowed, spring plowed, listed, subsoiled, 

 disked, green manured, or summer tilled. Some of these are again 

 subdivided to show the previous crop. To illustrate: The table for 

 Judith Basin (Table V) shows that there were five plats of whea^ 

 each year grown on fall-plowed land. On two of these the wheat 

 followed corn, on two it followed oats, and on one it followed wheat. 

 The average yield on fall plowing as given is the average of the five 

 plats, not the average of the given averages. To obtain these aver- 

 ages it is necessary to use the figures as many times as there were 

 plats averaged in obtaining them. The succeeding columns need 

 no explanation, as they are the yields for each year as indicated and 

 the average of each method for the whole period of years. In the 

 last column, where the average appears under the heading "Average," 



