Restoring soil function and resilience to degraded grasslands

Lead Research Organisation: University of Manchester
Department Name: Earth Atmospheric and Env Sciences

Abstract

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.

Technical Summary

Soil degradation presents a major threat to food security, economic development, and human wellbeing. One such hotspot of soil degradation is the Qinghai-Tibetan plateau, which contains the largest area of grassland on the Eurasian continent, and covers 25% of the land area in China. Grasslands cover 65% of the Qinghai-Tibetan plateau and are crucial for providing food and ecosystem services for rural people, largely through traditional livestock grazing. However, stocking rates on these grasslands have more than doubled in recent years, contributing to massive grassland degradation and soil erosion, and increased poverty of rural people. Further, these problems are exacerbated by climate change, especially extreme events such as droughts, which are increasing in frequency and making soils more vulnerable to erosion. A key starting point for the restoration of degraded grasslands is rebuilding soil functioning and resilience to climate change. We recently discovered, via our BBSRC research, that manipulating grassland plant functional diversity can be used to enhance soil functions of fundamental importance to soil health; knowledge that we propose can provide a basis for restoring functioning of degraded grassland soils of the Qinghai-Tibetan plateau. Our goal here is to tackle this challenge by: (a) conducting novel research to test the idea that plant functional diversity can help to restore soil health and resilience to degraded grasslands; and (b) building a multi-disciplinary team, including key stakeholders, with the capacity to develop robust solutions for the restoration of soil functioning and resilience to degraded grassland in this and other low to middle income countries. A key outcome will be a road map for a future, more wide-ranging consortium to conduct research on sustainable grassland management, including consideration of agronomic practices and socio-economic factors, to promote economic development and welfare on the Qinghai-Tibetan plateau.

Planned Impact

The main beneficiaries of our research will be scientists, policy makers and land managers concerned with the restoration of soil functioning in degraded grasslands of the Qinghai-Tibetan plateau and other regions, and, in the longer term, grassland herders who will implement new approaches to grassland restoration developed in this project. Our project also addresses fundamental questions about the functioning and resilience of grassland soils in this region, and will draw together experts working on related topics in other LMICs; as such, our project will generate new scientific understanding of the functioning of grasslands and their resilience to future climate change. Finally, our project will also be of interest to the general public. The Qinghai-Tibetan plateau is an iconic place and is fast becoming a major eco-tourism destination; as such, we expect considerable interest in our project among the general public with interests in this region.

Engagement with stakeholders: The principal vehicle for engagement and dissemination of our findings is via WP3, which sets out to build a multi-disciplinary research consortium with the capacity to develop policy and management tools, based on sound ecological and socio-economic principles, to restore soil functioning and resilience to degraded grasslands in this and other LMICs. We take a step-by-step approach to capacity building, which will involve (1) a participatory regional meeting in Xining, China, in May 2017, which will include local experts and stakeholders with interests in grassland restoration and soil functioning on the Qinghai-Tibetan plateau, building on existing links from our previous NERC ESPA Development Grant and the contacts of our project partners; (2) a systematic literature review to develop a framework for grassland restoration and sustainable management for resilience to climate change, that is underpinned by scientifically relevant approaches to soil restoration and improvement; (3) a 'Global Grasslands Summit', to be held in Manchester, Nov 2018, which will engage grassland and soil experts and stakeholders from China, other LMICs, and the UK with the goal of developing core understanding of key solutions to grassland degradation and sustainable grassland soil management; and (4) Finally, at the end of the project in Feb 2019, we will hold a final project meeting in Xining, China, with the aim of consolidating understanding and putting together a 'road map' for a future comprehensive research proposal aimed at sustainable grassland management to promote economic development and welfare in this and other LMICs.

Dissemination of research findings: A key mechanism for dissemination of research findings from our research will be the publication of peer reviewed papers in leading international journals, and the presentation of research findings at international meetings. Our goal is to publish at least two research papers, each based on WP 1 and WP 2, and an overview conceptual paper on 'sustainable solutions to grassland degradation" based largely on the 'Global Grassland Summit' to be held in Manchester, Nov 2018. In addition to publication of our work, we will encourage the PDRA's to present findings at national and international conferences.

To raise public awareness: We have a strong track record of being actively involved in outreach activities. Here we will For this project, we will raise public awareness via two primary routes. First, we propose to make a short film on grassland degradation and the work we are doing to tackle the problem, focussing on building healthy soil; second, we will use the "Global Grassland Summit" in Manchester as a vehicle to promote awareness of our research and its longer-term goals.

Transferable skills training: A key outcome will be the delivery of highly trained staff with training in multi-disciplinary approaches required to address major GCRF challenges in sustainable grassland management in LMICs.

Publications

10 25 50
 
Description The aim of our project is to develop novel, plant community-based approaches to restore soil functioning for plant production and resilience to climate change on degraded grasslands of the Qinghai-Tibetan plateau and Inner Mongolia, which are some of the most impoverished grassland regions of the world. To do so, we established degradation and restoration gradients on the alpine meadows of the Qinghai-Tibetan plateau with partners from the North West Institute of Plateau Biology, Chinese Academy of Sciences (NWIPB-CAS) and conducted a comprehensive field survey of above-/below-ground properties together with partners from Lancaster University to identify key factor(s) driving the degradation and restoration processes. In addition, several manipulative mesocosm experiments were set up in partnership with Lancaster University and the Institute of Grassland Research, Chinese Agricultural Academy of Sciences (IGR-CAAS) to test important ecological concepts possessing the potential to enhance success of grassland restoration. Overall, we aimed to use the combination of knowledge gained from these field and mesocosm studies to better assist management and restoration of degraded grasslands.

Key findings of each experiment are as follows:

1. Shifts in above- and below-ground properties during alpine grassland degradation and restoration - To identify critical interrelated factor(s) driving the degradation and restoration processes of the alpine meadows on the Qinghai-Tibetan Plateau, we conducted a field survey in conjunction with partners from Lancaster University and NWIPB-CAS in August 2018. We measured shifts in the vegetation community and a wide range of soil physical, chemical and biological properties along degradation and restoration gradients. Preliminary results showed that as the degree of grazing-induced degradation increases, the shift in vegetation community composition from grass- to forb-dominated and the reduction in plant below-ground biomass were associated with the decline in soil physical structure and increase in soil nutrient availability. In addition, soil tilling - as part of the current restoration practice - was likely to improve the re-establishment of grasses by suppressing the emergence and competition from forbs, reducing soil nutrient availability, and increasing soil water retention (in terms of soil permeability). Our preliminary results demonstrate that soil physical properties - while often overlooked - are important aspects to consider alongside soil chemical and biological properties during grassland restoration, and that grassland degradation is associated with declines in vegetation diversity, root biomass and soil physical, chemical and biological properties. The findings from this study were presented at the British Ecological Society's 2018 and 2019 Annual Meeting, at a series of public lectures at Lanzhou University, China, June 2019, and at our stakeholder workshop in Xining, June 2019, and data are currently being analysed and written up for publication.

2. Resilience of soil microbial communities to extreme drought - We tested the resilience of soil microbial communities along degradation and restoration gradients of the alpine meadows on the Qinghai-Tibetan Plateau in the event of an extreme drought. With the assistance of our partners from NWIPB-CAS, we used growth chambers to incubate soils collected from along the degradation and restoration gradients established during the field survey, and then subjected a subset of the soils to a 28-day-experimental-drought before re-wetting to assess resilience of the microbial communities. The experiment was completed in 2019 and the soils are data are complete and ready to be analysed and written up for publication. We will determine the resilience of soil microbial communities from sites of contrasting quality to drought by comparing the differences in soil respiration and the degree of changes in ecological interactions among microbial operational taxonomic units ('drought' vs 'no-drought').

3. Influence of soil microbial communities on below-ground root traits and soil physical structure - We set up a mechanistic mesocosm-glasshouse study in June 2018 in collaboration with our partners from Lancaster University to understand how contrasting levels of soil microbial diversity from high plant diversity pristine grassland vs low diversity arable land influence soil physical structure via plant rooting traits. We collected soils from a pristine grassland 'Site of Special Scientific Interest' in Parsonage Down, Wiltshire, and soils from an adjacent arable wheat farm. We used these field-collected soils to inoculate mesocosms containing heat-sterilised soils planted with either a grass, a legume, or a forb species, or a combination of two or three species from the different plant functional groups. Preliminary analyses on the inocula and bulk soils suggest that the heat sterilisation treatment was effective in suppressing microbial activity, and the soil microbial community of the pristine sites was contrastingly different from that of the arable sites. Further, plant identity, particularly the common non-nitrogen-fixing forb species (Plantago lanceloata), had a stronger influence on soil conditioning than the various types of soil microbial inocula. The experiment was harvested in July 2019, and data are complete and being prepared for analyses and publication.
Exploitation Route Our research outputs will be of interest to a range of academic groups, including soil scientists, environmental scientists, agronomists, and ecologists with interests on controls on grassland soil functioning and global change impacts on ecosystem processes in grassland ecosystems.

Our research will also be of interest to restoration ecologists and those concerned with understanding how best to restoring soil functioning to degraded ecosystems, including grasslands, as studied here, but also other ecosystem types. As highlighted in a recent UN report, some 33% of the world's soils are moderately to highly degraded, and 25-40 billion tons of topsoil are lost annually as a result of soil erosion (FAO 2015). Soil degradation is hence a global concern and the concepts and management tools developed here will be of interest to those concerned with the restoration and sustainable management of soils across LMICs.

Finally, there is growing interest in the understanding the factors that control resilience of ecosystem functioning to climate extremes, including vegetation functional diversity, as studied here. Our research will provide new insights into the influence of plant functional diversity on resilience of soil functions across soils and how this is affected by degradation.
Sectors Agriculture, Food and Drink,Environment

 
Description The results were presented at a final Qinghai-Tibetan Plateau Grassland Restoration Stakeholder Meeting, Xining, June 2019, including a wide range of stakeholders, including herders, advisors, academics, and various local groups. The workshop considered various and often contrasting perspectives of stakeholders concerning the ecological, socio-economic, cultural and agricultural value of grasslands and grassland restoration. Results are being synthesised and plans are being made to complete a policy document from the findings for wider dissemination, and we are exploring ways of incorporating findings into policy.
First Year Of Impact 2019
Sector Agriculture, Food and Drink,Environment,Culture, Heritage, Museums and Collections
Impact Types Cultural,Policy & public services

 
Description International symposium on Above- and Below-Ground Biodiversity for Sustainable Ecosystems, AgrosScope 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Keynote lecture on soil microbial community responses to climate extremes: resistance, resilience and transitions to alternative states. Symposium on Above- and Below-Ground Biodiversity for Sustainable Ecosystems, AgrosScope, Zurich, Nov 2019.
Year(s) Of Engagement Activity 2019
 
Description Keynote lecture, NERC STARS Annual Conference, Windermere 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact Keynote talk at STARS annual conference, Windermere, Jan 2019
Year(s) Of Engagement Activity 2019
 
Description PhD Workshop Alpine Biology and Global Change, University of Innsbruck 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Postgraduate students
Results and Impact Plenary lecture on soil microbial community responses to climate extremes: resistance, resilience and transitions to alternative states, PhD Workshop Alpine Biology and Global Change, University of Innsburck, Jan 2020.
Year(s) Of Engagement Activity 2020
 
Description Qinghai-Tibetan Plateau Grassland Restoration Stakeholder Meeting 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Qinghai-Tibetan Plateau Grassland Restoration Stakeholder Meeting (2019) was held at the North-West Institute of Plateau Biology, Xining, China, 20 June 2019
Year(s) Of Engagement Activity 2019
 
Description Round table discussion Chinese Academy of Science, Max Plank Institute Round Table, Shanghai, Nov 2019. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact Invited member and international expert with presentation on research challenges related to soil biodiversity and ecosystem functioning under global change: resistance and resilience to climate extremes. Chinese Acedemy of Science, Max Plank Institute Round Table, Shanghai, Nov 2019.
Year(s) Of Engagement Activity 2019