Continuousgrazing by sheep or cattle is a widespread extensive farming system, with low inputs and outputs.
Extensive farming most commonly means raisingsheep andcattle in areas with low agricultural productivity, but includes large-scale growing ofwheat,barley,cooking oils and othergrain crops in areas like theMurray-Darling Basin inAustralia. Here, owing to the extreme age and poverty of the soils, yields per hectare are very low, but the flat terrain and very large farm sizes mean yields per unit of labor are high.Nomadic herding is an extreme example of extensive farming, where herders move their animals to use feed from occasional rainfalls.
Extensive farming is found in themid-latitude sections of most continents, as well as in desert regions where water for cropping is not available. The nature of extensive farming means it requires less rainfall than intensive farming. The farm is usually large in comparison with the numbers working and money spent on it. In 1957, most parts ofWestern Australia had pastures so poor that only onesheep to the square mile could be supported.[1]
Just as the demand has led to the basic division of cropping and pastoral activities, these areas can also be subdivided depending on the region's rainfall,vegetation type and agricultural activity within the area and the many other parentheses related to this data.
Extensive farming can have the following problems:[3]
Yields tend to be much lower than withintensive farming in the short term.
Large land requirements limit the habitat of wild species (in some cases, even very low stocking rates can be dangerous), as is the case withintensive farming.
Less profitable then intensive farming per unit of area.
Extensive farming was once thought to produce moremethane andnitrous oxide per kg of milk than intensive farming.[4] One study estimated that the carbon "footprint" per billion kg (2.2 billion lb.) of milk produced in 2007 was 37 percent that of equivalent milk production in 1944.[5] However, a more recent study byCentre de coopération internationale en recherche agronomique pour le développement found that extensive livestock systems impact the environment less than intensive systems.[6]
^Thomas, Tyrone (2000)My Environmental Exposé, Hill of Content, pp. 42–50;ISBN0-85572-301-7
^Johnson, K. A.; Johnson, D. E. (August 1995). "Methane emissions from cattle".Journal of Animal Science.73 (8):2483–92.doi:10.2527/1995.7382483x.PMID8567486.
