- published: 10 May 2011
- views: 5499
Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature reserves. It can also be cause by immobile, travel restricted populations of native or non-native wild animals.
It reduces the usefulness, productivity, and biodiversity of the land and is one cause of desertification and erosion. Overgrazing is also seen as a cause of the spread of invasive species of non-native plants and of weeds. It is not caused by nomadic grazers in huge populations of travel herds, such as the American bison of the Great Plains, or migratory Wildebeests of the African savannas, nor by holistic planned grazing.
Sustainable grassland production is based on grass and grassland management, land management, animal management and livestock marketing. Grazing management, with sustainable agriculture and agroecology practices, is the foundation of grassland-based livestock production since it affects both animal and plant health and productivity. There are several new grazing models and management systems that attempt to reduce or eliminate overgrazing like Holistic management and Permaculture
In cricket, a follow-on is where the team that bats second is forced to take its second batting innings immediately after its first, because the team was not able to get close enough to the score achieved by the first team batting in the first innings. If the second team to bat scores substantially fewer runs than the first team, the first team have the option of enforcing the follow-on, instructing the second team to bat again immediately. In this case the sequence of batting innings will be first team, second team, second team and then, if needed, the first team again. This is in contrast to the normal progression of batting innings which is first team, second team, first team, second team.
The rules governing the circumstances in which the follow-on may be enforced are found in Law 13 of the Laws of Cricket.
The number of runs by which a team must lead to enforce the follow-on upon its opponent is determined by Law 13 of the Laws of cricket, which takes the length of the match into consideration: