Impact of grassland management by mob grazing on carbon sequestration

Are you interested in Geosciences?

This post is a half time technical post combined with a research studentship opportunity. You will be preparing materials and equipment for practicals, assisting in equipment maintenance and demonstration of safe use and providing technical support for our geography, environmental and agriculture research, teaching and consultancy.

It is essential that you are educated to HND/ Degree/ NVQ level 3 in a sports science or physiology subject or have equivalent in service experience. Additional experience of working in a physical geography or geosciences laboratory in a technical role would be an advantage. Adaptable and eager to learn you will be self-motivated and an excellent communicator with experience of team working. Numeracy and an ability to demonstrate techniques are also essential.

The post is combined with a research studentship;

Aims of project

The aim of the project is to measure the impact of mob grazing of cattle on soil organic matter levels to assess the potential of this livestock management regime to contribute to environmental management through carbon sequestration in soils.

Brief project outline

The potential of soils to sequester organic carbon has long been recognized, but is of increasing interest now that this has been identified as a potential way to mitigate against rising CO2 levels and climate change. An increasing number of studies are assessing how land management, across agriculture, forestry and moorland, can be adapted to increase carbon sequestration in soils (see for example Dawson and Smith, 2007; Soussana et al, 2004, Rounsevell and Reay, 2009; Freibauer et al, 2004). Studies of turnover of soil carbon have identified the role that disturbance can play in promoting breakdown of soil organic matter (SOM) and release of CO2. These reviews recognize the potential of reducing tillage, and transferring marginal croplands to grassland. Further, studies are now examining how grassland can best be managed to maximize the build up of SOM, in forms which are more stable and recalcitrant. There is a need to determine environmentally benign methods of raising livestock.

Mob grazing is a particular style of management of grazing cattle in which livestock move through sections of available pasture every 6-24 hours (Chapman, 2012). While on a compartment, livestock eat grass, trampling the remainder and their manure into the soil. Once moved on, the grassland has a lengthy period of recovery and regrowth before grazing is repeated. Mob grazing is believed to support the build up of organic matter in the soil, may increase carbon sequestration, so impacting positively on carbon sequestration in soils, and therefore could potentially impact on greenhouse gas levels. Furthermore, enhancing pasture-fed systems reduces the need for grains for overwintering, therefore reducing the environmental impact associated with growing grain for meat production.

The proposed project will seek to investigate the impact of mob grazing on soil organic matter and carbon sequestration. This research seeks to develop collaborative research, with scientists working with farmers. Researchers have already identified groups of farmers practising mob grazing in the Tamar valley, Devon, and Hertfordshire, as well as a network of farmers across the UK, drawing in part on the Pasture Fed Livestock Association.

Work plan outline

The following workplan has been developed assuming a part-time PhD candidate spending 50% of their time on the project, taking 6 years to complete the study.

1. Undertake a comprehensive literature review to collate and synthesis existing research on aspects of soil organic matter levels under mob grazing livestock systems.
2. Work with farmers who currently practice mob grazing to gather in-depth information regarding their beliefs and evidence for the benefits of mob grazing.
3. Develop an appropriate methodology to test the impact of mob grazing on soils, specifically organic carbon levels, but possibly also soil biodiversity (which will contribute to turnover of soil organic matter). This will be developed on farms based in Hertfordshire.
4. Detailed on farm monitoring of the impacts of mob grazing on a wider sample of mob-grazed farms across England.

Year 1: Literature review to synthesise existing research; Identify mob grazing farmers.
Year 2: Write up literature synthesis; Gather in depth information from mob grazing farmers about perceived benefits; Develop and begin pilot of methodology to test impact of mob grazing on soil organic matter
Year 3: Begin on farm monitoring of impacts of mob grazing on farms
Year 4: Continue data collection implementing data on wider farms across England
Year 5: Begin analysis of data; update literature review
Year 6: Writing up

There has been some discussion of linking this project to Rothamsted Research (North Wyke) where further detailed research on mob grazing under more controlled conditions could be carried out. If this is appropriate, further funds could be applied for over the course of the project to implement this research beyond year 4.

There is potential to link this research to UG / PG research projects looking at soil biodiversity and or grassland sward composition.

Contact Details:

If this interests you, please phone Jenny Harman, Technical Manager, on 01707 285184 or Malcolm Green, Senior Technical Manager on Hatfield 01707 284617 for an informal talk.

Closing Date: 30 November 2017

Reference Number: 015257

The University offers a range of benefits including a pension scheme, professional development, family friendly policies, child care vouchers, a fee waiver of 50% for all children of staff under the age of 21 at the start of the course, discounted memberships at the Hertfordshire Sports Village and generous annual leave.

Apply online at http://www.herts.ac.uk/contact-us/jobs-and-vacancies