8 BULLETIN 214, U. S. DEPARTMENT OF AGRICULTURE. 



Under the subhead "Green manured" are given the yields of wheat 

 following the plowing under of rye, peas, or sweet clover, as speci- 

 fied. This treatment is in 4-year rotations in which one of the other 

 crops is corn and the other is one of small grain. 



At each station several plats of spring wheat are grown on sum- 

 mer-tilled land. One of these is from land alternately summer 

 tilled and cropped to wheat; one is from a 3-year rotation of summer 

 tillage, wheat, and oats; and others are from 4-year rotations in 

 which the other crops are corn or potatoes and oats or barley. 



The method of summer tillage practiced has been of the intensive 

 type. The ground is fall plowed and clean cultivation is continued 

 through the next year and until the wheat is seeded in the second 

 spring. In some cases it is necessary in order to destroy weeds to 

 replow during the summer when the land is fallow. At other sta- 

 tions summer-tilled plats are plowed but once. Experiments not 

 here reported are under way to ascertain the best method of fallowing. 

 Indications are that equally good results can be obtained with a less 

 intensive method than has been practiced in the investigations here 

 reported. 



The yields given in these tables begin with the second year of crop 

 production at each station. All crops are produced the first year on 

 land uniform in its treatment. In some cases an entire crop has 

 been lost by hail. These years are not considered in computing 

 averages, as the crops resulting from all methods alike were destroyed. 



By the use of the basic data which follows in Tables II, III, and 

 IV there has been compiled a second part embodying a summarized 

 statement of the table of yields for each station. In this summary 

 are brought together in different form the yields in the first part of 

 such table. The value of the average yields thus obtained is shown 

 together with the cost of production (as computed from the avail- 

 able data). In the last line of the table is given the average profit 

 or loss resulting from the production of wheat by the method shown 

 at the head of the column. Loss is indicated by the minus sign. 



COMPARISON OF CULTURAL METHODS ON THE BASIS OF COST. 



In order to make a» comparison of the relative profits or losses of 

 the several cultural methods, as shown in the second part of the 

 table for each station, it was necessary to establish the average cost 

 of production under each of these methods. The methods under 

 study vary a great deal in the labor involved and in the consequent 

 cost of preparation. Table IV has therefore been compiled in order 

 to show the average cost of the methods under study as determined 

 from the data of eight of the stations having the most trustworthy 

 records. An average of the records for 5^ years at each station has 



