FORAGE PRODUCTION IN EARLY SPRING 63 



in this weakened condition is readily killed by further close or 

 premature grazing. 



Sampson ^ has shown that the removal of herbage several times 

 in a season, especially if the first harvest is made a few days 

 after growth has started, seriously weakens the plant and im- 

 mediately decreases its forage production. In the Blue Moun- 

 tains of northeastern Oregon, and again in the Wasatch Moun- 

 tains of Utah, the writer harvested monthly, for three years in 

 succession, various species of bunchgrasses and other plants, 

 three cuttings being made each year on one plot and once a 

 season on another plot. Most of the plants so treated lived 

 through the period of the experiment, but at the end of the third 

 year only a few weak spears of leafage per plant were produced. 

 Moreover, each season, as the experiment of frequent harvesting 

 progressed, the time at which growth began was correspondingly 

 delayed, until finally no flower stalks were sent up. On the 

 other hand, plants of equal vigor when the test was started, but 

 whose herbage was not clipped until the seed crop had ripened, 

 were approximately 150 per cent greater in volume at the be- 

 ginning of the third year of treatment than those harvested three 

 times each season, and the forage yield from them was about 

 300 per cent greater. Furthermore, the growth of the vigorous 

 plants began in the spring ten to fifteen days earlier than on the 

 frequently clipped plots. Then, too, the leafage was quite as 

 abundant as where the plants were protected yearlong. Nor 

 was the difference in the development of the plants variously 

 treated confined to the aerial growth. Repeated examinations 

 of the roots in the autumn at the end of the third year of treat- 

 ment showed that the plants clipped monthly were practically 

 devoid of plant foods, whereas those not harvested until the seed 

 had matured contained a superabundance of food materials 

 (Fig. 17). 



An elaborate series of cropping tests with various forms of 

 bunchgrasses was carried out by the writer at the Great Basin 



1 Sampson, Arthur W., "Range Improvement by Deferred and Rotation Graz- 

 ing." U. S. Dept. of Agr. Bui. 34, p. 3, 1913. 



