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

粮农组织最近表示，在60年内，地球上的表土将因土壤退化而丧失。在英国，土壤研究人员认为“英国只剩下100个庄稼了”。这些说法的科学基础尚不清楚。然而，它们确实指出了全球对世界土壤未来的担忧，以及了解土壤能够持续提供关键土壤功能的重要性：土壤寿命。从中等(10s年)到长(100s年)的时间尺度，我们假设土壤的寿命取决于土壤生产过程(如矿物风化)和那些去除土壤的过程(如有机物分解)之间的平衡。这些变化可能发生得很快，通常是由于人为干预，例如，土地利用变化后的侵蚀使表层土壤消失，或者更缓慢地发生，例如，有机碳对气候变化的反应。也许令人惊讶的是，我们对土壤生产率的了解存在很大差距。如果我们要预测土壤的寿命，填充这些是至关重要的。到目前为止，对土壤生产率的调查仅限于美国西海岸和南澳大利亚的半自然植被，几乎没有对农业用地进行测量。在英国，我们只有一项来自Bodmin Moor的测量。这个博士项目的目的是：1.确定英国三个不同地点的土壤形成率；2.开发一个能够预测土壤寿命的模型；3.预测每个地点土壤连锁区的土壤寿命。

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.