Chair: Christine Watson (SRUC)
Soils are the foundation of agricultural production but also inextricably linked to food and culture. In this session we explore some of those links and also explore tools and methods to improve soil structure and crop nutrition.
Dr Bruce Ball opened this session with an inspiring speech on soil structure and its importance, spanning from powerful metaphors comparing a soil to our psyche, to an array of concrete experiences to increasing soil awareness. The priority has to be set on soil quality. The real challenge is therefore to increase awareness on soil vulnerability, guiding soil assessment by local stakeholders a visual evaluation charts, and increasing the sensibility through group activities focused on handling, concretely, the soil, thus (re)creating a physical and intimate contact with this crucial resource.
The most basic principle to preserve soil health is maximising soil cover. Cover crops and living mulches are a key strategy in this direction for organic farmers and growers. However, how to choose the right species is frequently an open and challenging question. Sally Westaway (ORC) presented the powerful Cover Crop and Living Mulch Toolbox developed by the EU FP7 OSCAR project. It is an online portal with information on a wide number of potential subsidiary crop species, including the expected advantages they can provide, their environmental needs and optima, in order to guide a wise crop choice. But there is more: it is not a ‘closed’ toolbox, as researchers, farmers and growers are encouraged to interact with the platform to update information.
Legumes are a key group of soil improving plants and, in current cropping systems in the UK, they are mostly found in leys. Mark Measures (IOTA) explored the potential of species diversity in mixtures to optimise the services provided by legumes, mainly N-fixing, and highlighted the key points to successful mixtures. Awareness of N partition into the plant is essential to choose species and fine-tune their management. Further, C/N ratio, Lignin and Polyphenol content were exposed as predictors of N release dynamics. Key species were presented, including White and Red Clover, Black Medic, Birdsfood Trefoil and, for annuals, Crimson Clover. Special attention has to be dedicated also to the inclusion of herbs, as they can strengthen the services provided by fertility-building mixtures.
The discussion that followed the presentations brought out the following points:
- Awareness on soil vulnerability can be fostered by providing farmers and other actors both by useful assessment tools and by field groups activities.
- The use of subsidiary crops can be made more effective when ICT tools as the ‘OSCAR Toolbox’ can provide farmers with complete and up-to-date information, and also be fed and constantly updated with empirical evidence.
- A special focus has to be set on species mixtures in leys, which have to be tested and selected at a very local scale.
Individual speaker presentations and abstracts
Developing connection with the soil can improve soil management and conservation and also integration and function in the food system. Soil connection is shown by physical contact and by comparison with the human psyche. Physical connection with the soil is commonly by sight, feel or smell such as when assessing the structural quality of the soil with a spade or from a soil profile. Soil structural quality influences crop yield and quality and tillage and nutrient inputs. Structure can be described and scored by using the Visual Evaluation of Soil Structure (VESS) which employs a spade test for the topsoil and a profile test for the subsoil. The soil is scored based on how hard it is to break up, the size and shape of aggregates, the amount and size of pores, the distribution and appearance of roots, the smell and colour. Connection by comparison with the human psyche helps the development within us of soil-like properties such as integration, networking and recycling. These can bring awareness of changes in food consumption and in lifestyle required for the success of agroecological approaches to feed us. For a brighter future, we not only need to conserve our soil, we need to become more like it.
The Cover Crop and Living Mulch Toolbox is one of the main outputs from the OSCAR European research project which focuses on developing sustainable Conservation Agriculture systems and increasing the diversity of cover crops and living mulches. The Toolbox consists of three main elements; a wiki; a species database; and a decision support tool, presented as a series of web based tools. The content draws on scientific literature, technical information and results from the field trials, it is partially user interactive and designed to be used by farmers, advisors, researchers and members of the general public. The Toolbox aims to make current knowledge on cover crops and living mulches widely available and will help you identify suitable cover crop and living mulch species and varieties as well as practical management advice. This workshop will take you through the development of the Toolbox and will include a short demonstration the different tools in the box.
Reliance on the use of legumes for the supply of nitrogen is fundamental to all genuinely sustainable farming systems. Over the years we have gravitated towards simpler mixtures with fewer legume species and sometimes no companion grasses due to ease of management and the very diverse characteristics of different forage legume species, including red, white and crimson clover, lucerne, sainfoin, trefoil, medic and vetch. We will discuss how and why we should be growing much more diverse legume mixtures in our leys and green manures, with real benefits for soil fertility and structure, forage production and biodiversity in a healthy farming system.