REVIEW: Nutrient stripping: The global disparity between food security and soil nutrient stocks

Abstract

1. The Green Revolution successfully increased food production but in doing so created a legacy of inherently leaky and unsustainable agricultural systems. Central to this are the problems of excessive nutrient mining. If agriculture is to balance the needs of food security with the delivery of other ecosystem services, then current rates of soil nutrient stripping must be reduced and the use of synthetic fertilisers made more efficient. 2. We explore the global extent of the problem, with specific emphasis on the failure of macronutrient management (e.g. nitrogen, phosphorus) to deliver continued improvements in yield and the failure of agriculture to recognise the seriousness of micronutrient depletion (e.g. copper, zinc, selenium). 3. Nutrient removals associated with the relatively immature, nutrient-rich soils of the UK are contrasted with the mature, nutrient-poor soils of India gaining insight into the emerging issue of nutrient stripping and the long-term implications for human health and soil quality. Whilst nutrient deficiencies are rare in developed countries, micronutrient deficiencies are commonly increasing in less-developed countries. Increasing rates of micronutrient depletion are being inadvertently accomplished through increasing crop yield potential and nitrogen fertiliser applications. 4. Amongst other factors, the spatial disconnects caused by the segregation and industrialisation of livestock systems, between rural areas (where food is produced) and urban areas (where food is consumed and human waste treated) are identified as a major constraint to sustainable nutrient recycling. 5. Synthesis and applications. This study advocates that agricultural sustainability can only be accomplished using a whole-systems approach that thoroughly considers nutrient stocks, removals, exports and recycling. Society needs to socially and environmentally re-engineer agricultural systems at all scales. It is suggested that this will be best realised by national-scale initiatives. Failure to do so will lead to an inevitable and rapid decline in the delivery of provisioning services within agricultural systems.