Restoring soil function and resilience to degraded grasslands

土壤退化对粮食安全和人类福祉构成重大威胁。正如联合国最近的一份报告所强调的那样，世界上约33%的土壤处于中度至高度退化状态，由于土壤侵蚀，每年流失的表土多达400亿吨。此外，这些问题在发展中国家尤其严重，那里的土壤侵蚀可能导致粮食产量急剧下降，并导致贫困和饥饿。人们对土壤退化的关注大多集中在可耕地上，但这也是全球草原的一个主要问题。草原占地球陆地面积的37%，对粮食供应和生计至关重要。青藏高原就是这样一个土壤严重退化的热点地区。该地区是欧亚大陆草原面积最大的地区，占中国陆地面积的25%。它也是地球上最高和最大的高原，面积250万平方公里，平均海拔4500米。大约有800万人生活在高原上，其中48%的人生活在贫困中，主要原因是农村人口赖以生存的草原大面积退化。草原覆盖了青藏高原65%的面积，在为农村人口提供食物和生态系统服务方面发挥着重要作用，主要是通过传统的放牧牦牛、绵羊和山羊，但也是用于中药的野生植物和真菌的来源。然而，近年来，这些草原上的牲畜放养率增加了一倍多，过度放牧造成了大规模的草地退化和土壤侵蚀，导致农村贫困加剧。气候变化也加剧了这些问题，尤其是日益频繁的干旱等极端事件，使土壤更容易受到侵蚀。目前，据估计，青藏高原约有30-50%的草地已经退化，在许多情况下，土壤已经完全失去了支持草地生产的能力，给当地人民带来了极端后果；这个地区是中国第三贫穷的地区，许多传统牧民生活贫困。尽管如此，土地管理者和政策制定者仍然困惑于如何将退化的草原恢复到曾经的健康状态，以及如何使它们能够更好地缓冲变幻莫测的气候变化。草地退化是由多种因素造成的，恢复草地并不是一件简单的事情。但关键是重建一个功能齐全的土壤，这是支持牲畜生长的植物所依赖的。我们还认为，这种土壤健康的恢复需要一种全面的方法，包括重建土壤的化学、物理和生物特性，而土壤的功能和对气候变化的适应能力取决于这些特性。我们的目标是恢复青藏高原退化草地土壤的肥力，增强其缓冲未来气候变化的能力。我们在英国草原上的研究表明，通过控制草地植物群落的多样性和组成，可以促进土壤的健康和恢复力。我们想测试这种方法，以恢复青藏高原退化草地土壤的功能和恢复力，从而有助于增加该地区的粮食生产和改善人类福利。为了实现这一目标，我们不仅计划开展新颖的研究，在青藏高原退化的土壤上测试我们在英国草原上发展起来的想法；此外，我们还将建立一支包括草地科学家和利益攸关方在内的多学科团队，有能力根据健全的生态和社会经济原则制定强有力的解决方案，以恢复我国和其他中低收入国家的土壤功能和对退化草地的恢复能力。

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.