Editing Rotational grazing (section)

==Weed control==
A well managed rotational grazing system has low pasture weed establishment because the majority of [[Ecological niche|niches]] are already filled with established forage species, making it harder for weeds to compete and become established.<ref name=IowaGuide2005/> The use of multiple species in the pasture helps to minimize weeds. Established forage plants in rotational grazing pasture systems are healthy and unstressed due to the "rest" period, enhancing the [[competitive advantage]] of the forage. Additionally, in comparison to grain crop production, many plants which would be considered weeds are not problematic in perennial pasture.<ref name=PastProfit/> However, certain species such as [[thistles]] and various other weeds, are indigestible or poisonous to grazers. These plant species will not be grazed by the herd and can be recognized for their prevalence in pasture systems.

A key step in managing weeds in any pasture system is identification. Once the undesired species in a pasture system are identified, an [[integrated pest management|integrated approach of management]] can be implemented to control weed populations. No single approach to weed management will result in weed free pastures; therefore, various cultural, mechanical, and chemical control methods can be combined in a weed management plan.<ref name=PastProfit/> Cultural controls include: avoiding spreading manure contaminated with weed seeds, cleaning equipment after working in weed infested areas, and managing weed problems in [[fencerow]]s and other areas near pastures. Mechanical controls such as repeated mowing, clipping, and hand weeding can also be used to effectively manage weed infestations by weakening the plant. These methods should be implemented when weed flower buds are closed or just starting to open to prevent seed production. Although these first two methods reduce need for [[herbicides]], weed problems may still persist in managed grazing systems and the use of herbicides may become necessary. Use of herbicides may restrict the use of a pasture for some length of time, depending on the type and amount of the chemical used.  Frequently, weeds in pasture systems are patchy and therefore spot treatment of herbicides may be used as a least cost method of chemical control.<ref name=PastProfit/><ref name=IowaGuide2005/>