2 BULLETIN 1170, U. S. DEPARTMENT OF AGRICULTURE. 



is one well worthy of serious consideration and careful experimenta- 

 tion, for the value of the products of pastures greatly exceeds that 

 of many of the important cultivated crops. As it has become neces- 

 sary to establish experiment stations for the purpose of studying 

 problems of crop production, the need of experiments bearing upon 

 pasture problems has also developed. In one instance the object is 

 to supply information about crops, while in the other it is to give 

 information on range and pasture management. The two problems 

 are intimately related. • 



The results obtained by the Office of Dry-Land Agriculture In- 

 vestigations in determining the possibilities and best methods of crop 

 production on the Great Plains early indicated the necessity of live- 

 stock production and the utilization of the native grasses as an 

 integral part of the farming system in the greater portion of the 

 area. It was not until the establishment of the field station near . 

 Mandan, N. Dak., however, that this phase of the investigations 

 could be undertaken. It was made possible because of the equipment 

 afforded this station and the desire of T. P. Cooper, director, and 

 Prof. J. H. Shepperd, vice director, of the North Dakota Agricul- 

 tural Experiment Station, to cooperate in this work in their State. 



The cooperative grazing experiment at the Northern Great Plains 

 Field Station, near Mandan, N. Dak., was begun in 1915. This ex- 

 periment is conducted by the Office of Dry-Land Agriculture In- 

 vestigations of the Bureau of Plant Industry, United States Depart- 

 ment of Agriculture, in cooperation with the North Dakota Agri- 

 cultural Experiment Station. The office mentioned furnishes the 

 land and equipment and conducts the details of the experiment. 

 The State furnishes the cattle used for grazing and follows them 

 with observations before they are put on the grass in the spring, 

 while they are on the pastures, and after they are removed in the 

 fall. The work of the State includes a study of economic feeding 

 and marketing, shipping, shrinkages, dressing percentages, and other 

 special livestock features. 



All the details of the grazing experiment, including the handling 

 and weighing of the cattle, the technical botanical studies, the tak- 

 ing of notes, and the keeping of records are under the immediate 

 supervision of J. T. Sarvis. All notes, records, and results of this 

 experiment are available for publication or other purposes alike to 

 the North Dakota Agricultural Experiment Station and to the 

 United States Department of Agriculture. 



The initial purpose of the experiment was to study the effect of 

 different intensities of grazing upon the native vegetation and to 

 note the gains of the cattle. The question of primary importance 

 was considered to be the number of acres of native range required 

 to feed a steer during the grazing season and at the same time enable 

 him to make a reasonable gain in weight. At the beginning of the 

 experiment it seemed that this would be an easy phase of the prob- 

 lem to determine. However, as the experiment progressed, other 

 factors arose which were of equal or superior significance. These are 

 (1) the effects of grazing upon the native vegetation, (2) the ex- 

 tent of gains of the cattle, and (3) the maximum utilization of the 

 vegetation. 



In a grazing experiment of this nature it is not only necessary 

 to recognize the species of plants that make up the native vegetation, 



