Increased Land Clearance for Crop Cultivation

The ingredients for animal feed concentrates are tradable on international markets and the effects of increased demand for livestock feed are likely to result in environmental effects at a distance from the locations where industrial animal production occurs. An increased demand for livestock feed concentrates results in an expansion and intensification of cultivated area and thus potentially exerts a wide range of pressures on the environment. This increased crop cultivation occurs at the expense of other forms of land use, especially pastures and forested areas. | Depletion of Resources Loss of Plant Varieties Loss of Wildlife Habitat Loss of Carbon to the Atmosphere Further Reading Environmental Assessment: Pressure State Response Indicators Policy Pressure and Policy Options Technology Options

Depletion of Resources

Land clearing to enable the expansion of crop production is a potential threat to the environment through: loss of biomass, habitat, biodiversity and to undesirable changes in the aesthetic aspects of the landscape. In addition there are direct effects of cropping on soils, water and air. Cultivation of the land results in erosion, loss of nutrients, loss of organic matter and depletion of fresh water resources. Soil quality could be restored through use of crop residues, composts, animal manure and crop rotations with legumes. However, these need to be supplemented with an increased use of organic fertiliser, which requires fossil energy for manufacturing and has the potential risk of nutrient losses (particularly N and P) to the environment through leaching or run-off.

Loss of Plant Varieties

Increasing land clearance for cultivation of crops leads to the loss of habitat and may ultimately result in the loss of plant species or varieties. A related issue is the loss of varieties of cultivated crops as a result of an increased reliance on high yielding varieties. The result is a reduction of both natural and agricultural biodiversity.

Loss of Wildlife Habitat

Increasing land clearance for cultivation of crops also leads to the loss of habitat used by wildlife. As a result of changing conditions in agricultural fields, many species of wildlife – especially birds – are undergoing significant population declines. For example, many species of British farmland birds have declined drastically as agricultural practices have changed resulting in the removal of hedgerows. Such loss of habitat has contributed substantially to the decrease in biodiversity in Europe over the last century. There is also evidence that species diversity and abundance are lower on those farms using chemicals as fertilisers and pesticides than on farms using organic farming techniques.

Loss of Carbon to the Atmosphere

Over the last century, the atmospheric concentration of CO2 has about doubled. Through photosynthesis, plants incorporate the carbon from CO2 and produce oxygen. Concerns about the threat of global climate change due to the greenhouse effect have caused considerable attention to be given to the role of vegetation, and of forests in particular, in locking up carbon – carbon sinks or carbon sequestration. The clearance of natural vegetation and its replacement by cultivated land generally results in an increase in atmospheric carbon. Conversely, encouraging the growth of forests is now widely seen as a means of sequestering carbon dioxide - and in so doing reducing the global build-up of CO2 levels. Clearance of forested land, either directly for livestock or indirectly for cultivation of animal feed, therefore has an impact on atmospheric CO2.

Further Reading

McNeely, J.A., Gadgil, M., Leveque, C., Padoch, C. & Redford, K. (1995). Human Influences on Biodiversity. Pp 711-821 in. Heywood, V.H. & Watson, R.T. Global Biodiversity Assessment. UNEP. Cambridge University Press. ISBN 0 521 56481 6.

Increased Use of Fossil Fuel for Transport and Processing of Concentrates

Increased Use of Fossil Fuel for Inputs (Mechanization, Fertilizers and Agro-chemicals)

Carbon Sinks

Carbon Sequestration

Carbon Sequestration on Pasture Land

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