New insights into soil formation, organic matter turnover and degradation of soils over long, decadal to millennial timescales

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The FAO has recently stated that within 60 years the topsoil of our planet will be lost via soil degradation . In the UK soil researchers have suggested that 'Britain has only 100 harvests left' . The scientific basis for these statements are unclear. However, they do point to the global concern over the future of the world's soils and the importance of understanding how long soils can continue to provide the critical soil functions: the soil lifespan.Over medium (10s of years) to long (100s of years) timescales we hypothesise that the soil's lifespan is dependent on the balance between the soil production processes e.g. mineral weathering, and those that remove soil e.g. organic matter decomposition. These changes may occur rapidly, often due to human interventions, for example the removal of the topsoil by erosion following land use change, or more slowly, such as changes in organic carbon in response to climate change. Perhaps surprisingly, there are major gaps in our knowledge of the rates of soil production. Filling these are critical if we are predict soil lifespan's . To date soil production rate investigations have been limited to semi natural vegetation on the West coast of the US and South Australia, with virtually no measurements in agricultural lands. In the UK we have only one measurement from Bodmin moor .The aims of this PhD project are to:1. Determine soil formation rates at three contrasting sites across the UK;2. Develop a model capable of predicting soil lifespans;3. Predict the soil lifespan for a soil catena at each of the sites.