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



over a series of years. The same is true as regards the gain per acre 

 produced. 



THE 100-ACRE PASTURE. 



The 100-acre pasture, which is grazed at the rate of one 2-year-old 

 steer to 10 acres, has produced an abundance of feed each season 

 that the experiment has been in progress. It has not been injured 

 by overgrazing but has slightly deteriorated because of undergraz- 

 ing, but not to the same degree or in the same way that other pas- 

 tures have deteriorated from overgrazing. This deterioration is 

 shown by the increased coarseness of the " weeds " and the accumu- 

 lation of old vegetation, which the cattle avoid as long as possible. 

 There has been enough forage produced in this pasture at all times 

 to allow the cattle to make nearly the maximum gains per head. 

 The size of the pasture, however, has resulted in low gains per acre. 

 An area of 10 acres is more land than is required to carry a steer 

 for five months during the summer season under a system of con- 

 tinuous grazing. Such an underutilization of land is not beneficial 

 to the native vegetation or to the cattle grazing upon it. 



THE 70-ACRE PASTURE. 



The 70-acre pasture, which is grazed at the rate of one 2-year-old 

 steer to 7 acres, has produced abundant feed to meet the require- 

 ments of the cattle and make the maximum gains per head. The 

 number of acres has kept it from producing a high gain per acre, 

 but its gains have been higher than in the 100-acre pasture. The 

 pasture has not been overgrazed nor has it shown the same effect of 

 undergrazing that is apparent in the larger pasture. An area of 

 7 acres approximately is required to graze a steer for five months 

 during the summer season under a system of continuous grazing. 

 In good years there will be an excess of forage, and in poor years 

 the forage produced will be sufficient to feed the usual number of 

 steers without overgrazing. In order to insure a pasture from over- 

 grazing under this system it is necessary that from 15 to 25 per cent 

 of the vegetation remain standing at the close of the season. When- 

 ever the vegetation under a system of continuous grazing falls below 

 this, the pasture is on the danger line of destructive overgrazing. It 

 should not be overlooked that this pasture has produced remarkably 

 well. 



THE 50-ACRE PASTURE. 



The 50-acre pasture is grazed at the rate of one 2-year-old steer 

 to 5 acres. It has not yielded enough forage to carry the cattle 

 through the season and produce maximum gains per head. The 

 gain per acre has been greater than that of the two larger pastures 

 because of the reduced acreage. During the first two years of the 

 experiment there was feed enough to enable the cattle to make gains 

 equal to those in the 70-acre pasture. Since that time the gains have 

 decreased because of feed shortage. During only one year has it been 

 necessary to move the cattle to another pasture before the close of the 

 season ; but they have lost weight toward the end of the season every 

 year since 1917. An area of 5 acres is not enough to insure forage 

 sufficient to carry a steer for five months during the summer without 



