EFFECTS OF BURNING ON FORAGE PRODUCTION 221 



ductivity of the soil and the continued production of forage; 

 on the perpetuation and healthy growth of the choicest and most 

 valuable plants; and, on mountain lands especially, on the 

 efficiency of the watershed for irrigation and on the supply of 

 water for domestic purposes as well as for navigation. 



EFFECTS OF BURNING ON FORAGE PRODUCTION 



The vegetation that remains on the ground at the end of the 

 season performs three unportant functions, (i) It enriches the 

 soil by the addition of humus and nitrogenous matter made 

 available through the decomposition of the roots and aerial 

 parts of the vegetation. (2) The humus in turn creates a sponge- 

 like condition in the upper soil layer which increases its capacity 

 to absorb water as it is received, thus making a maximum amount 

 of water available for absorption by plant life during the dry 

 part of the season. (3) Whatever old Vegetation remains after a 

 proper season of grazing, because it acts more or less as a mulch 

 on the soil surface, decreases the evaporation from the soil and 

 thereby conserves the moisture for plant growth. At the same 

 time the semi-decomposed vegetable matter helps to prevent 

 the soil from baking. Hence it acts as a regulator of the temper- 

 ature and evaporation, both of which are controlhng factors in 

 the development of plant Hfe. An area upon which the soil is 

 exposed is sometimes subject to such wide and sudden fluctua- 

 tions in temperature and moisture content that the vegetation 

 which it supports, being often killed or seriously injured, is re- 

 placed by more drought-enduring plants. On the other hand, 

 on areas whose soil fertility is high, and whose surface is partly 

 protected by plant remnants from excessive evaporation, there 

 is found a stable and luxuriant type of vegetation, generally the 

 most profitable type the area is capable of producing. 



It is contended that the only way to maintain in the soil the 

 mineral and organic matter absorbed by the plant cover is to 

 return to mother earth in the form of ash, as large a proportion 

 of these constituents as is possible. Burning what vegetation 

 remains at the end of the growing (grazing) season obviously 

 defeats this plan and at once upsets the natural balance between 



