Restoring soil function and resilience to degraded grasslands
- Richard Bardgett (PI) University of Manchester
- John Quinton (Co-I) Lancaster University
- Nickolas Ostle (Co-I) Lancaster University
Funding: BBSRC GCRF
Soil degradation presents a major threat to food security and human wellbeing. As highlighted in a recent UN report, some 33% of the world’s soils are moderately to highly degraded and as much as 40 billion tons of topsoil are lost annually as a result of soil erosion. Further, these problems are especially acute in developing countries, where soil erosion can cause dramatic declines in food production and result in poverty and hunger. Much focus on soil degradation is centered on arable lands, but it is also a major problem across the world’s grasslands, which cover ~ 37% of the earth’s land surface and are of major importance for food supply and livelihoods. One such hotspot of severe soil degradation is the Qinghai-Tibetan plateau. This region is the largest area of grassland on the Eurasian continent, covering 25% of the land area in China. It is also the highest and largest plateau on Earth with an area of 2.5 million km2 and an average altitude of 4500 m. Some 8 million people live on the plateau, of which 48% live in poverty, largely due to widespread degradation of the grasslands on which rural people depend. Grasslands cover 65% of the Qinghai-Tibetan plateau and play a major role in providing food and ecosystem services for rural people, largely through traditional yak, sheep and goat grazing, but also as a source of wild plants and fungi used in traditional Chinese medicine. However, livestock stocking rates on these grasslands have more than doubled in recent years, and overgrazing has contributed to massive grassland degradation and soil erosion, leading to increased rural poverty. These problems are also exacerbated by climate change, especially extreme events such as droughts, which are becoming more frequent, making soils more vulnerable to erosion. At present, estimates suggest that some 30-50% of grasslands on the Qinghai-Tibetan plateau are degraded, and in many cases soils have completely lost their ability to support grassland production, with extreme consequences for local people; many traditional herders live in poverty in this region, which is the third poorest in China. Despite this, land managers and policy makers remain puzzled about how to restore degraded grasslands to their once healthy state, and how to make them better able to buffer the vagaries of climate change.
Grassland degradation is caused by many factors, so restoring them is not straightforward. But key is the re-building of a fully functioning soil, on which plants that support livestock depend. We also argue that this recovery of soil health requires a holistic approach, involving the rebuilding of chemical, physical and biological properties of soil on which its functioning and resilience to climate change depends. Our goal is to restore fertility to degraded grassland soils of the Qinghai-Tibetan plateau and enhance their ability to buffer future climate change. We build on our research in UK grasslands where we have shown soil health and resilience can be promoted through manipulating the diversity and make up of grassland plant communities. We want to test this approach for restoring the functioning and resilience of degraded grassland soils of the Qinghai-Tibetan plateau, thereby helping to increase food production and improve human welfare in this region. To achieve this, we not only plan to carry out novel research, testing our ideas developed in UK grasslands on the degraded soils of the Qinghai-Tibetan plateau; but also we will build a multi-disciplinary team, including grassland scientists and stakeholders, with the capacity to develop robust solutions, based on sound ecological and socio-economic principles, for the restoration of soil functioning and resilience to degraded grassland in this and other low to middle income countries.