

How Much of A plANT shoulcJ bE qRAZEd? 



One of the most important factors in determining when and where to schedule and 

 distribute grazing use is knowing how much grazing certain plant communities can 

 withstand. The grazing tolerance for most plants depends on the basic makeup of the 

 plant, season of use, soil, climate, vigor and health of plants, and competition with other 

 plant species. Plant health can be adversely affected by grazing when greater than 60 

 percent of the current year's growth is removed unless additional rest is provided from 

 grazing. 



To ensure that management objectives are being met, set target grazing use levels for each 



unit in your grazing schedule. A target grazing use level is a percentage of the plant's 



weight that can be removed on a yearly basis without having a negative impact on the 



plant's health. This level must he established on a site-specific basis that recognizes 



resource needs as well as management unit objectives. After assessing the condition of 



the rangeland in a grazing unit, set a target level tor grazing use that balances animals' 



nutritional needs with the need to maintain a healthy plant community. Consider current and planned resource conditions, scheduled rest periods, 



and the grazing tolerance of key species. Setting a target level for key plant species, though not an objective in itself, will give you a reference point for 



evaluating grazing use throughout the unit. 



Generally, if the plant community is relatively stable and healthy, plan target grazing use levels for no more than 50 to 60 percent use of the key 

 species. The plant must have adequate leaf area for photosynthesis and recovery of growth after grazing. If the plant community is not stable, or if less 

 desirable plants are competing for space, set lower target use levels. This percentage can be correlated for each plant species to a specific stubble 

 height remaining after grazing. For example, on an average year, 50 percent use on bluebunch wheatgrass correlates to about a 4'inch stubble height. 

 Remember that this level must be determined at each site. 



To ensure lUul uuma^cincnl objectives are bciu^ i 

 levels for each unit in your grazing schedule. 



ct tar^Li grazing use 



V i'i ^1 



! I ■-\--'..irt'-'JJ l| ( 



d^ 



m 



J '.li 'U-iin''y--fi.'i'i: i; 



Unmunched 



Slight Munch (A) Slight Munch (B) Light Munch Moderate Munch Heavy Munch 



Seedheads 



clipped off 



10% use 



20% nubbed 

 off close 

 10% use 



40% nubbed 

 off close 

 50% use 



70% nubbed 

 off close 

 50% use 



Kcft HAi^A<A*t^efU P'Ui^^cet (^MP^) ^jOi CjoAoM^ 



Whole plant 



nubbed off close 



70% use 



11 



