Input constraints to food production: the impact of soil degradation

Global demand for food is increasing in terms of the quantity, quality and reliability of supplies. Currently, over 90 % of our food is grown on (or in) a virtually irreplaceable, non-renewable natural resource - the soil. This paper examines the latest research on selected soil degradation processes (soil erosion by water, compaction, loss of organic matter, loss of soil biodiversity and soil contamination) and specifically how they impact on food production. Every year, an estimated 12 million hectares of agricultural land are lost to soil degradation, adding to the billions of hectares that are already degraded. It is estimated that soil degradation leads to a potential loss of 20 million tonnes of grain per annum, but this is likely to be an underestimate, because the evidence base is limited in identifying direct impacts of soil degradation on food production. Some soil management practices have been used to mask the effects of soil degradation on food production (e.g., additions of chemical fertilisers), but comprehensive soil conservation practices are required to respond to the multiple problems of soil degradation if the world is to be able to feed more than 9 billion people by 2050.