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，世界上约有33%的土壤中度至高度退化，每年因土壤侵蚀而损失的表土多达400亿吨。此外，这些问题在发展中国家尤为严重，因为土壤侵蚀可能导致粮食产量急剧下降，并造成贫穷和饥饿。对土壤退化的关注主要集中在可耕地上，但它也是世界草原的一个主要问题，草原覆盖了地球陆地表面的37%，对粮食供应和生计至关重要。其中一个严重土壤退化的热点是青藏高原。该地区是欧亚大陆上面积最大的草原，占中国陆地面积的25%。它也是地球上最高和最大的高原，面积为250万平方公里，平均海拔4500米。约有800万人生活在高原上，其中48%生活在贫困中，主要原因是农村人口所依赖的草原普遍退化。草原覆盖了青藏高原的65%，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，主要是通过传统的牦牛，绵羊和山羊放牧，但也是传统中药中使用的野生植物和真菌的来源。然而，近年来，这些草原上的牲畜饲养率增加了一倍多，过度放牧造成了大规模的草原退化和土壤侵蚀，导致农村贫困加剧。这些问题还因气候变化而加剧，特别是干旱等极端事件日益频繁，使土壤更容易受到侵蚀。目前，估计青藏高原约有30-50%的草地退化，在许多情况下，土壤完全失去了支持草地生产的能力，对当地人民造成了极端后果;许多传统牧民生活在贫困之中，这是中国第三大贫困地区。尽管如此，土地管理者和政策制定者仍然对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气候变化的变幻莫测感到困惑。草原退化是由许多因素造成的，因此恢复它们并不简单。但关键是重建一个功能齐全的土壤，支持牲畜的植物依赖。我们还认为，这种土壤健康的恢复需要一个整体的方法，包括重建土壤的化学，物理和生物特性，其功能和对气候变化的适应能力取决于。我们的目标是恢复青藏高原退化草原土壤的肥力，增强其缓冲未来气候变化的能力。我们建立在我们在英国草原的研究基础上，我们已经表明，通过操纵草原植物群落的多样性和组成，可以促进土壤健康和恢复力。我们希望测试这种方法，以恢复青藏高原退化草原土壤的功能和恢复力，从而帮助增加该地区的粮食产量和改善人类福祉。为了实现这一目标，我们不仅计划开展新的研究，在青藏高原退化的土壤上测试我们在英国草原上开发的想法;而且我们还将建立一个多学科团队，包括草原科学家和利益相关者，有能力根据合理的生态和社会经济原则，在这个国家和其他中低收入国家恢复土壤功能和对退化草地的复原力。

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.