ROTATION AND CULTURAL METHODS AT EDGELEY, N. DAK. 15 



the humus content of dry-land soils, thus increasing the yields. It 

 was argued that they could be used in extensive or exclusive grain 

 farming where barnyard manure was not available in adequate 

 quantity. 



Experiments were instituted to determine the effect of using 

 winter rye, field peas, and sweet clover for green manures. At the 

 Edgeley station this group of experiments was confined to 4-year 

 rotations in which the land is green manured once every four years. 

 The crops in the other three years are wheat, oats, and corn. Each 

 green manure is used in two rotations. In one rotation oats follow 

 the green manure and the wheat is after corn, which follows the oats. 

 In the other the wheat follows the green manure and the oats are on 

 corn ground. 



Rotation No. 14 is rye for green manure, oats, corn, and wheat ; 

 rotation No. 15 is rye for green manure, wheat, corn, and oats; rota- 

 tion No. 16 is peas for green manure, oats, corn, and wheat ; rotation 

 No. IT is peas for green manure, wheat, corn, and oats ; rotation No. 

 32 is sweet clover for green manure, oats, corn, and wheat ; and rota- 

 tion No. 31, is sweet clover for green manure, wheat, corn, and oats. 

 The sweet clover in these rotations is sown with the preceding wheat 

 or oats and plowed under when in blossom in its second year. 



For comparison with these green-manure rotations are two similar 

 ones having bare fallow in place of the green manure. These are 

 rotations Nos. 18 and 19, already described. In rotation No. 18 the 

 wheat is on fallow and the oats on corn ground, and in rotation No. 

 19 the oats are on fallow and the wheat on corn ground. 



The green-manure rotations are fairly comparable with the fallow 

 rotations in that each of them involves the loss of the use of the land 

 for one year in four. After the green-manure crop is turned under 

 the plats are treated as fallow for the remainder of the season. They 

 are essentially modified fallows, requiring the extra expense of seed 

 and seeding. 



Rotations Nos. 14, 15, 16, and 17 were started in 1906 and the other 

 four in 1907. 



The results are difficult to determine in all their relations, on 

 account of the natural variations in plat yields. The 1 study at the 

 present time is further complicated by the fact that the last period 

 of four years has been one of low yields and two of the four have 

 been bad rust years. With all their discrepancies and apparent 

 contradictions, however, they point to a general conclusion : The 12- 

 year averages from 1908 to 1919, inclusive, afford no basis of hope to 

 increase yields by the use of green manures. One possible exception 

 to this will be considered farther on. The expense of the green 

 manures precludes all possibility of their profitable employment. 

 Further, when a crop is grown there is no basis of justification for 

 plowing it under in the hope of increasing the yield of succeeding 

 crops. 



