192 BULLETIN 1301, U. S. DEPARTMENT OF AGRICULTURE 
The plan of grazing the rotation pasture is shown in Table 29. 
This plan illustrates the application and management of deferred and 
rotation grazing. The 70-acre area is divided by cross fences into 
three divisions, all approximately the same. The divisions are des- 
ignated as A, B, and C. When this pasture was first grazed in 1918. 
division A was grazed in the spring; division B in the summer; and 
division C was allowed to mature its crop normally and was grazed 
in the fall.. In 1919 division B was grazed first, division A second, 
and division C was again deferred until third before grazing, or after 
the crop had matured without disturbance. During the “following 
seasons divisions A and B were in turn treated as was division C in 
1918 and 1919. The grazing starts in the spring of each season, so 
that a division that has been deferred until fall for two successive 
years is not grazed first. This 1s done so that any seedlings that may 
have started from the second year’s seeding may have a chance to 
become more firmly established before the division is. orazed. 
As far as has been possible to determine, there has been no meas- 
urable increase of any of the species by reseeding in the rotation 
pasture. This was no doubt influenced to some extent by the very 
unfavorable seasons. The advantage gained in this region by this 
system of grazing is in the physiological effect upon the plants. 
This experiment does not take into consideration winter grazing, 
which should not be depended upon in this section of the plains. 
The seasonal period of grazing has been five months during the sum- 
mer. Grazing has started from May 15 to June 1 and continued to 
October 15 or November 1. Four years of the seven the seasonal 
grazing started in May and three years on June 1. 
TaBLE 29.—Plan of grazing the deferred and rotation pasture at the Northern Great 
Plains Field Station for the 6-year period, 1918-1923, inclusive 
Divisions of pasture, and periods Divisions of pasture, and periods 
| of grazing of grazing 
Year Bec I | Year z <r 
parses B © ey A Bo vee 
1 & | a Peseta A ee Dene Pe a ere ee ee eee 4 £ 
iO Re ae Ses ae Spring____| Summer__) Fall. | 214 eines Ree | Summer__} Fall_____._ Spring. 
LOR Fey t Sec | Summer__}| Spring-_-_- Do. 1922 eee eS ib oes 1) te Summer__| Do. 
LO2QE ERs ee Lae Sprang 2-5 |SBalleess yes SUMMICEs | e923 eee ees [22200 2eaeers Spring___-. Summer, 
| 
The cattle used in the grazing experiment are 2-year-old grade 
steers of the standard beef breeds. Figure 8 illustrates the “type 
used during 1922. 
The 2-year-old beef steer was decided upon as the unit, as (a) he seemed to be 
most used by ranchmen figuring on this question; (b) he has about the average 
eapacity for consumption between yearlings, cows, and large steers; (c) he is 
not disturbed like the heifer, by periods of cestrum or by calving during the trial.!® 
The cattle are weighed individually at the end of regular 30-day 
periods. Whenever the grazing season starts before June 1 they 
are weighed at the start in May and again on May 31. This is done 
so the periods will correspond to the months. At the beginning and 
close of the season the cattle are weighed on three consecutive days. 
16 Shepperd, J. H. Carrying capacity of native range grasses in North Dakota. Jn Jour. Amer. Soc. 
Agron., v. 11, p. 129-142, pl. 3-5. 1919. 
