LEGUMES AXD GRASSES 



Table 2. — Relative yields of wheat and corn for two periods of time and loss 

 in soil nitrogen in various rotations, Mandan, N. Dak., 1915-18 and 

 1947-53 ' 







Relative 



vield of — 







Rotation 



Wheat 



Corn 



Loss 

 in 

 soil 





1915 



to 

 1918 



1947 



to 

 1953 2 



1915 



to 

 1918 



1947 



to 

 1953 



nitrogen 



Corn, wheat, small grain 



Corn, wheat, small grain, grass 



Corn, wheat, small grain, sweetclover. 



Corn, wheat, small grain, alfalfa 



Corn, wheat, small grain, manure 



Continuous wheat 



Percent 

 100 



86 

 105 

 110 

 101 



96 



Percent 

 100 

 97 

 124 

 140 

 149 

 113 



Percent 

 100 

 76 

 94 

 97 

 94 



Percent 

 100 

 110 

 110 

 123 

 116 



Percent 

 34 

 30 

 30 

 19 

 3 

 18 



Continuous corn 



111 



6S 



42 











1 Data from Haas (££). 



* 4-year average, as 3 years omitted because of hail damage. 



doubled by fertilization. Fertilizers 

 were more effective in increasing 

 wheat yields than the use of legumes 

 and grass. 



Chemical and Physical Effects of 

 Legumes and Grasses on Soils 



In 1949, a study was initiated at 

 Mandan on cultivated Cheyenne 

 fine sandy loam and Agar silt loam 

 to determine the effects of legumes 

 and grasses on the maintenance of 

 organic matter and nitrogen. 3 Fer- 

 tilizers were applied annually. Sod 

 crops were mowed and the hay 

 removed. Wheat was combined 

 and straw was returned to the soil. 

 The sod was plowed in 1955. Soil 

 samples were taken in 1949 and 

 1955. Nitrogen changes for the 0- 



3 Haas, H. J. fertility management 



USE OF LEGUMES AND MANURES FOR THE 

 MAINTENANCE OF ORGANIC MATTER AND 

 NITROGEN. AND SUBSTITUTION OF FERTI- 

 LIZED CONTINUOUS WHEAT FOR WHEAT- 

 FALLOW. Paper presented at ARS-SCS 

 Research Application Workshop, Rapid 

 Citv, S. Dak., Feb. 16-17, 1960. (Alimeo 

 Rpt.) 



711-108—64 2 



to 24-inch depths were measured 



(table 3). 



The data indicate that crested 

 wheatgrass and continuous wheat 

 without fertilization both resulted 

 in nitrogen losses on the fine sandy 

 loam soil; however, these losses 

 were small. Where fertilizers were 

 applied or legumes were grown, 

 small nitrogen increases occurred on 

 both soils. The silt loam soil 

 showed greater nitrogen increases 

 than did the sandy loam soil. 



In this same study, one-half of 

 each plot on the Cheyenne soil was 

 mowed and the residue left on the 

 surface from 1949 through 1955. 

 All plots were plowed in 1955 and 

 cropped to spring wheat in 1956 and 

 1957; in 1957 samples of the soil 

 were tested. Xo fertilizer was 

 applied dining 1956 and 1957 except 

 on the continuous-wheat plots that 

 had previously received 30 pounds 

 of both X and P 2 5 . Nitrogen gains 

 and losses for the 0- to 24-inch 

 depths were measured (table 4). 



Haas' data indicate that wheat 

 and nonfertilized crested wheat- 



