LEGUMES AND GRASSES 



17 



time the following spring. Green 

 manuring had no beneficial effects 

 on the second- and third-year crops. 



In 1937, Bell (2) reported on 

 dryland crop investigations at the 

 North Montana Branch Station at 

 Havre. Winter rye, pea, and sweet- 

 clover green manures had a de- 

 pressing effect on yields of small 

 grains the following year compared 

 with ordinary fallow (table 10). 



In 1959, Army and Hide (1) 

 reported on the effects of green- 

 manure crops on dryland wheat 

 production at Havre, Huntley, and 

 Moccasin for 28- to 43-year periods. 

 They found that, compared with 

 ordinary fallow, green-manure fal- 

 low crops of winter rye, field peas, 

 and sweetclover decreased yields of 

 spring wheat at Havre, Huntley, 

 and Moccasin an average of 3.2, 

 3.6, and 3.8 bushels per acre, 

 respectively. At Huntley, from 

 1913 to 1951, yields of winter wheat 

 were decreased 8 bushels per acre 

 by green-manure fallow. At Moc- 

 casin, from 1909 to 1951, yields of 

 winter wheat were increased 0.7 

 bushel per acre by green-manure 

 fallow. 



In 1956, Post and Army (67) 

 examined dryland fallow spring 

 wheat yields to determine whether 

 or not productivity had declined 

 with time. They compared yields 

 for the first 10 years of cultivation 

 at Havre, Huntley, and Moccasin 

 with those for a later 10-year 

 period (1942-51). The yields in- 

 creased with time at Havre and 

 Huntley — from 14 to 18 bushels per 

 acre at Havre and from 16 to 17 

 at Huntley. The yields decreased 

 at Moccasin — from 19 to 16 bushels 

 per acre. Rainfall from seeding to 

 harvest was 6.5 inches at Havre 

 and Huntley and 8.4 inches at 

 Moccasin for both periods. Soils 

 at Havre and Huntley are deep; 

 the soil at Moccasin is shallow over 

 gravel. 



Windecker and Geeseman 4 found 

 that crested wheatgrass in rotation 

 was beneficial. Two rotations were 

 used for comparison — crested wheat- 

 grass for 8 years, flax, fallow, 

 spring wheat, oats; and fallow, 

 spring wheat, oats. 



From 1947 to 1957, yields of 

 spring wheat in the crested wheat- 

 grass rotation were increased 4.2 

 bushels per acre and oat yields 7.5 

 bushels per acre. 



Crested wheatgrass hay reached 

 peak production of one-half ton 

 per acre in the second and third 

 year and then gradually declined 

 each year. Flax yields were low — 

 an average of 2.9 bushels per acre. 



In spite of increased wheat and 

 oats yields in the grass rotation, 

 the low yields of flax and hay made 

 this an unproductive rotation. The 

 year of fallow prior to the wheat 

 and oats probably removed the 

 deleterious effect of depleted soil 

 moisture that is characteristic of 

 sod crops. 



Chemical and Physical Effects of 

 Legumes and Grasses on Soils 



In 1959, Army and Hide (1) 

 reported the carbon and nitrogen 

 analyses of the 0- to 12-inch depths 

 of soil from the green-manure study 

 at Havre, Huntley, and Moccasin. 

 Green-manure crops of winter rye, 

 field peas, and sweetclover had not 

 materially affected the nitrogen and 

 carbon contents of the soil. They 

 suggested that green manures 

 should not be used for dryland 

 spring and winter wheat production 

 on soils of the Brown and Chestnut 

 Great Soil Groups. 



4 Windecker, Claude, and Geese- 

 man, G. E. SUMMARY REPORT OF AGRON- 

 OMY, SOILS AND HORTICULTURE RESEARCH 

 WORK AT THE NORTH MONTANA BRANCH 

 STATION, HAVRE, MONT. Mont. Agr. 



Expt. Sta. [Mimeo. Rpt.] 1957. 



