Editing Rotational grazing (section)

==Nutrient availability and soil fertility==

If pasture systems are seeded with more than 40% legumes, commercial nitrogen [[fertilization]] is unnecessary for adequate plant growth.<ref>{{cite journal |last1=Berntsen |first1=J. |last2=Grant |first2=R. |last3=Olesen |first3=J. E. |last4=Kristensen |first4=I. S. |last5=Vinther |first5=F. P. |last6=Molgaard |first6=J. P. |last7=Petersen |first7=B. M. |title=Nitrogen cycling in organic farming systems with rotational grass-clover and arable crops |journal=Soil Use and Management |date=June 2006 |volume=22 |issue=2 |pages=197–208 |doi=10.1111/j.1475-2743.2005.00016.x |bibcode=2006SUMan..22..197B |s2cid=96402221 }}</ref> Legumes are able to fix atmospheric nitrogen, thus providing nitrogen for themselves and surrounding plants.

Although grazers remove nutrient sources from the pasture system when they feed on forage sources, the majority of the nutrients consumed by the herd are returned to the pasture system through manure. At a relatively high [[stocking rate]], or high ratio of animals per [[hectare]], manure will be evenly distributed across the pasture system. The nutrient content in these manure sources should be adequate to meet plant requirements, making commercial fertilization unnecessary.<ref name=PastProfit/> Rotational grazing systems are often associated with increased [[soil fertility]] which arises because manure is a rich source of [[organic matter]] that increases the health of soil. In addition, these pasture system are less susceptible to [[erosion]] because the land base has continuous ground cover throughout the year.

High levels of fertilizers entering waterways are a pertinent environmental concern associated with agricultural systems. However, rotational grazing systems effectively reduce the amount of nutrients that move off-farm which have the potential to cause [[environmental degradation]].<ref name="Blanchet, K. 2003">Blanchet, K., Moechnig, H., and DeJong-Hughes, J.  2003.  [http://www.extension.umn.edu/distribution/livestocksystems/components/DI7606.pdf Grazing systems planning guide] {{webarchive|url=https://web.archive.org/web/20130618055354/http://www.extension.umn.edu/distribution/livestocksystems/components/DI7606.pdf |date=2013-06-18 }}. USDA-NRCS and University of Minnesota Extension and University of Minnesota Water Resource Center</ref> These systems are fertilized with on-farm sources, and are less prone to leaching as compared to commercial fertilizers. Additionally, the system is less prone to excess nutrient fertilization, so the majority of nutrients put into the system by manure sources are utilized for plant growth.<ref name="Blanchet, K. 2003"/> Permanent pasture systems also have deeper, better established forage root systems which are more efficient at taking up nutrients from within the soil profile.<ref name=IowaGuide2005/>