|Title||Life cycle assessment to evaluate the environmental impact of biochar implementation in conservation agriculture in Zambia|
|Publication Type||Journal Article|
|Year of Publication||2012|
|Authors||Sparrevik, Magnus, Field John, Martinsen Vegard, Breedveld Gijs D., and Cornelissen Gerard|
|Journal||Environ. Sci. Technol|
Biochar amendment to soil is a potential technology for climate change mitigation. It may, in addition, be a valuable soil fertility enhancer for agricultural purposes in sandy or weathered soils. A life cycle assessment including ecological, health and resource impacts has been conducted for field sites in Zambia to evaluate the overall impacts of biochar for agricultural use. In this study, conventional agricultural methods were compared to conservation farming using cultivation growth basins and precision fertilization with and without biochar addition. Three different biochar production methods were evaluated: traditional earth-mound kilns, improved retort kilns and micro top-lit updraft (TLUD) gasifier stoves. The results confirm that the use of biochar in conservation farming is beneficial for climate change mitigation purposes. However, when including health impacts from particle emissions originating from biochar production, conservation farming plus biochar from earth-mound kilns generally results in a larger negative effect over the whole life cycle than conservation farming without biochar addition. The use of cleaner technologies such as retort kilns or TLUDs can overcome this problem, mainly because fewer particles and less volatile organic compounds, methane and carbon monoxide are emitted. These results emphasize the need for a holistic view on biochar use in agricultural systems. Of special importance is the biochar production technique which has to be evaluated from both environmental/climate, health and social perspectives.