1919] FIELD CROPS. _ 823 



manure per acre to brome grass during a period of 11 years produced an in- 

 crease of 72 per cent in yield of hay, and of 22 per cent of nitrogen and 33 per 

 cent of phosphorus in the surface 7 in. of soil. The increase in yield thus far 

 obtained is estimated to be worth 60 cts. for each ton of manure applied. 



Clover has produced a higher yield of hay than timothy, and the yields of 

 succeeding crops of wheat and corn have been higher after clover. As an aver- 

 age of the 3 years, 1914-1916, in which clover and timothy were followeil by 

 wheat and corn the clover rotation is estimated to have produced a gross 

 income of $i3.61 per acre more than the timothy rotation. Clover is also said 

 to be a more profitable crop in the rotation than peas. In 1914 clover pro- 

 duced 3.22 tons more hay per acre than peas, and in 191.5 wheat following 

 clover yielded 6.9 bu. per acre more than that following peas. 



The highest average income, $29.01, was secured from a six-year rotation 

 consisting of potatoes, wheat, barley, and alfalfa 3 years. Owing to the failure 

 of alfalfa in 1910 and 1911 the average income on the duplicated plat of this 

 rotation was only $1S. In the second ranking rotation, consisting of corn, 

 wheat, barley, clover, and wheat, when two cuttings of clover were obtained 

 the average annual gross income was $24.49 per acre. On account of the better 

 distribution of labor and the larger acreage of grain the latter rotation is 

 deemed better suited to Red River Valley conditions. 



Wheat, barley, timothy, brome grass, and potatoes responded to applications 

 of farm manure, the average value of the increased yield being $1.16 for each 

 ton of manure during a period of 3 years. Clover, peas, and alfalfa have not 

 responded to applications of manure. 



It is estimated that the increase from one ton of rotted manure has been 

 worth $1.22 as an average of five plats, and the average increase on seven plats 

 from one ton of fresh manure worth $1.13. Considering the cost of the extra 

 handling of rotted manure, it is regarded as more profitable to haul the manure 

 directly from the barn to the field. 



The second part of the bulletin (pp. 216-251) has to do with studies made 

 in connection with a series of experiments previously described (B. S. R., 28, 

 p. 338). These studies were planned in an effort to ascertain the effects of 

 German millet, broom corn millet, corn, potatoes, and bare fallow on wheat 

 grown in rotation with them, and also the influence of these crops upon the 

 soil moisture and available nitrogen supply of succeeding wheat crops. Obser- 

 vations were made during the growing seasons of 1911-1918, inclusive, on the 

 moisture and nitrate content of the soil at different stages in the growth of 

 crops in various places in the rotation, and the data are presened in tabular 

 form. The results secured may be summarized as follows : 



German millet and broom corn millet improved the condition of the soil for 

 wheat when the land was comparatively new and free from weeds. Where 

 such a cropping system was followed continuously, however, the yield of wheat 

 was reduced. In these experiments the second and third wheat crops following 

 millet have frequently yielded more than the first crop where this cropping 

 system had been practiced for 8 years or more, this being specially noticeable 

 when the first wheat crop was preceded by a heavy crop of millet. 



The growing of corn once in four years resulted in the maintenance of the 

 yield of the first and second wheat crops following the corn, but the yield of 

 the third crop decreased. The beneficial effects of the corn crop extended over 

 a shorter time on old land than on new land, as indicated by the fact that the 

 first wheat crop yielded 5.72 bu. more than the third crop in the last four years 

 of the experiment while the preceding 4-year period it yielded but 1.95 bu. more. 

 158071°— No. 9—20 3 



