UNEP has just released the United Nations Environment Programme’s (UNEP) Year Book 2012 and it highlights assessments indicating that some kinds of conventional and intensive agriculture are triggering soil erosion rates some 100 times greater than the rates at which nature can form soil in the first place.
There could also be profound implications for climate change. Soils contain huge quantities of carbon in the form of organic matter that in turn binds the nutrients needed for plant growth and allows rainfall to penetrate into underground aquifers. By 2030, without changes in the way land is managed, over 20 per cent of terrestrial habitats such as forests, peatlands and grasslands in developing countries alone could be converted to cropland aggravating losses of vital ecosystem services and biodiversity.
Achim Steiner, UN Under-Secretary General and UNEP Executive Director said: “The thin skin of soil on the Earth’s surface is often one of those forgotten ecosystems but it is among the most important to the future survival of humanity. The Year Book cites many options for improved, sustainable management such as no-till policies to ones that can assist in productive agriculture without draining peatlands,”
The Benefits of Soil Carbon
The Year Book encourages the development of universally agreed and reproducible field and laboratory methods for measuring, reporting and verifying changes of soil carbon over time. Carbon stocks can be enhanced by ensuring that carbon inputs to the soil are greater than carbon losses. For example:
- Forests have considerable potential for reducing greenhouse gas emission to the atmosphere by storing large stocks of carbon both above and below ground.
- Improvements of grasslands offer a global greenhouse gas mitigation potential of 810 Mt of CO2 up to 2030, almost all of which would be sequestered in the soil.
- In croplands, integration of several crops in a field at the same time can increase organic material, soil biodiversity and soil health, as well as increase food production, particularly for subsistence farmers.
- Paludiculture is an innovative alternative to conventional peatland agriculture. It involves biomass cultivation on wet and rewetted peatlands, which can contribute to climate change mitigation by reducing emissions through rewetting of drained peatland soils, and by replacing fossil resources with renewable biomass alternatives.
The United Nations Environment Programme’s (UNEP) Year Book 2012 can be downloaded at UNEP.
IMAGE CREDIT: Flickr User Soil Science
根据2012年联合国环境署年鉴，由于人类不可持续的土地使用方式，在过去的四分之一世纪，24%的世界土地资源的健康与生产力出现了严重退化。年鉴着重指出，一些传统密集型农业生产方式使土壤的退化速度超过自然界土壤形成速度的约100倍。如果人类不改变土地管理方式，那么至2030年，发展中国家20%的陆地环境，如森林、湿地与草地，将变成耕地，这将直接严重损害生态系统服务功能与生物多样性。