MISCELLANEOUS PUBLICATION 1271, U.S. DEPARTMENT OF AGRICULTURE 



Grazing systems should be designed for spe- 

 cific objectives, and need to be flexible (in stock 

 numbers and season of use) to match climatic 

 variations and, therefore, plant responses. Flexi- 

 bility should also be adequate to allow for periods 

 of environmental stress, such as droughts. In de- 

 signing management systems, all factors and con- 

 straints affecting the entire management plan 

 should be considered, for example, location of 

 fences, water, and alternative areas for stock. Al- 

 lowance should be made for animals other than 

 domestic stock. 



In all the examples mentioned at the meeting, 

 experimental rotational grazing s3 T stems were in- 

 ferior to, or no better than, yearlong grazing. 

 However, it was recognized that considerable 

 scope exists for applying flexible, seasonal graz- 

 ing practices designed from a knowledge of plant 

 responses. One reason for the lack of good re- 

 search data on such practices is the difficulty of 

 designing experiments involving flexible treat- 

 ments. 



Research results from the short grass plains 

 and the California annual grass type in the 

 United States, and from Mitchell grass in Aus- 

 tralia indicate that there is a critical level or 

 amount below which vegetation cannot be grazed 

 without impairing its recuperative capacity. The 

 specific critical levels are 300 pounds per acre of 

 blue grama for the short grass plains, 500 

 pounds per acre of mulch in the annual type, and 

 a 5-inch stubble for Mitchell grass. There was a 

 strong suggestion that such a critical level exists 

 for each range type, and that it is the most im- 

 portant factor affecting range management. 



An associated aspect, on which there was gen- 

 eral agreement, is that insufficient attention has 

 been given to the region a few centimeters above 

 and below the soil surface. It is in this region 

 that rainfall is partitioned into runoff and soil 



water, that most decomposer activity occurs, and 

 that seeds and nutrients accumulate. The condi- 

 tions in this region, therefore, have a profound 

 effect on the future of the ecosystems. 



The importance of managing for maximum seed 

 crops has been over-emphasized in the past. An- 

 nual plants will produce adequate seed supplies 

 under most grazing systems and certainly under 

 yearlong grazing. Some perennials do not need 

 £o produce seeds and most others only need to 

 seed occasionally. 



Different range types require different criteria 

 for judging condition and trend and, therefore, 

 for assessing success or otherwise of management. 

 The original or climax condition is not necessarily 

 the best. Care is needed in extrapolating results, 

 standards, and management systems from one 

 range type to another. The whole infrastructure 

 of range inventor} 7 and range monitoring tools 

 (particularly range condition and trend stand- 

 ards), which is taken for granted in the United 

 States, is not available in Australia. The same 

 principles probably apply but need to be adapted 

 to Australian conditions. There is a dearth of 

 range management training, at both research and 

 operator level, in Australia. 



Conservative range management practices need 

 to be based on a knowledge of the phenology of 

 range plants. The general lack of information on 

 the growth and development of 'range plants 

 (particularly shrubs and forbs) and their re- 

 sponse to defoliation makes it difficult to devise 

 soundly based grazing systems, and even to inter- 

 pret the results of some grazing trials. For ex- 

 ample, it is not always clear whether experimental 

 results are due to rest periods or grazing periods. 

 Plant physiologists have an important role to 

 play in providing information in a form which 

 can be used in devising management strategies. 



