EFFECTS OF DIFFERENT SYSTEMS OF GRAZING. 5 



plants can spread by means of the ripened seed. This can be accomplished by 

 dividing the range up into separate pastures and grazing the different fields in 

 rotation. 2 



The Forest Service of the United States Department of Agricul- 

 ture later developed and put into practice in the management of 

 grazing lands within the national forests the system of " deferred 

 and rotation grazing." 3 A similar system has also been applied on 

 a large range in the Southwest. 4 



In 1918 a 70-acre pasture managed under the system of deferred 

 and rotation grazing was established. This is locally referred to 

 as the " rotation pasture." It is not a new system of range manage- 

 ment developed with the experiment at Mandan, but rather a direct 

 application in the northern Great Plains of a system of grazing 

 already highly developed. This system, as applied in this experi- 

 ment, follows closely the detailed plan outlined in the Yearbook for 

 1915. 5 The only change made at Mandan, in the plan, is to transfer 

 the cattle from the division grazed in the fall to the one grazed in 

 the spring of the same year. This is done for a short time near 

 the close of the season when the feed supply in the fall division 

 becomes short and inferior to that in the spring division. There is 

 usually some growth made in the spring division after the cattle 

 are transferred to another unit. If this growth is grazed after 

 maturity there are no ill effects to the vegetation, and there is no 

 reason why this secondary growth should not be utilized if neces- 

 sary. Another change is that the number of cattle is not reduced 

 during the second season of fall grazing on a unit. 



In 1921 a field of brome-grass was established adjoining the 

 pastures. This will be grazed in direct relation to the native pastures 

 under the continuous system of grazing and should furnish in- 

 formation on the relative value of a cultivated grass as compared 

 with the native vegetation for grazing purposes. It was planned 

 to start this pasture in 1919, but the seasons were so unfavorable 

 that it was not possible to do so until the spring of 1921. The ad- 

 dition of the cultivated pasture now makes the grazing experiment 

 very complete without being too complicated. While it would have 

 | been desirable to start all pastures at the same time, the fact that 

 they were not so started should not make the results obtained any 

 less valuable. Each pasture or system of grazing must stand on 

 its own merit. In order to be of most value, a pasture under any 

 system of grazing must maintain its productiveness over a series of 

 years and not be greatly influenced by conditions that may ob- 

 tain for one or two seasons only. 



LAND USED FOR THE EXPERIMENT. 



The area of land used for the grazing experiment was formerly 



I a school section, located about ?4 miles south of Mandan, upon what 



is locally known as the Custer Flats. The section for a number of 



2 Smith, Jared G. Forage conditions of the prairie region. In Yearbook, U. S. Dept. 

 Agr., 1895, pp. 309-324, figs. 70-74. 1896. 



8 Sampson, Arthur W. Range; improvement by deferred and rotation grazing. U. S. 

 Dept. Agr. Bill. 34, 16 pp.. 5 pis. 1913. 



4 Jardine, James T., and Hurtt, L. C. Increased cattle production on southwestern 

 ranges. U. S. Dept. Agr. Bui. 588, 32 pp., 12 pis., 2 figs. 1917. 



5 Jardine, James T. Improvement and management of native pastures in the West. 

 In Yearbook, U. S. Dept. Agr., 1915, pp. 299-310, pis. 69-72. 1916. 



