H3: Functional biodiversity for growers
Chair: Phil Sumption (Garden Organic)
It has always been assumed that the encourage-ment of biodiversity on horticultural holdings is a good thing in the control of pests and diseases, soil fertility management and general system robustness. This session provides guidance on functional biodiversity and pointers on how to manage it. (Organised with OGA)
The central role that biodiversity plays in crop production is well recognised by organic growers who appreciate the pest control, decomposition and pollination services the ‘wild’ biodiversity on their land provides. This session explored how to encourage and support these beneficial beasties, with a focus on bumblebees and earthworms. Rob Brown from the University of Reading talked about the importance of legume diversity for providing an extended floral resource to support bumblebees throughout the season, reporting his results from the LegumeLINK project. He also identified the need for sympathetic management of non-crop habitats such as field margins, headlands, beetle banks and hedgerows, as nesting sites. Dan Carpenter (Earthworm Man!) from the Natural History Museum illuminated the wonderful world of earthworms, and how the 26 species in the UK can be separated into 4 ecological groups based on their feeding and burrowing activities and physiology. Enhancing earthworm populations on your land needs careful soil management to provide a stable environment and plentiful organic matter for feed. As with pollinators, non-crop habitats provide an essential resource, as reservoirs from which earthworms can re-invade the cropped fields. An inspiring presentation from Iain Tolhurst (Tolhurst Organic Produce) showed that his ‘whole-system’ approach put biodiversity at the core of his production system, with fruit and vegetables simply a by-product. Diversity of the planned (i.e. cropped) and unplanned (i.e. non-cropped) components of his system was essential to support functional biodiversity, with Tolly admitting his growing love for growing weeds! Tolly stressed the importance of observation in understanding what is going on in your fields, and how to make changes to increase beneficial insects and reduce pest outbreaks.
- Managing for biodiversity needs to be integrated into the whole system
- Identifying what resources are needed (e.g. nesting habitat, feed resources) is important
- Observation of your system is critical to support a systems approach to management.
- Join the Earthworm Society of Britain to support greater understanding of our earthworms.
Individual speaker presentations and abstracts
Rob Brown (University of Reading/ORC): Diverse legumes for increased pollination (PDF 1.9MB)
Agriculture is reliant on a number of ecosystem services that support, maintain and regulate the production of goods. As well as maintaining wildlife diversity, pollination is a highly valuable service within the agricultural sector, contributing to 35% of global food production (23 x 108 Mt). Within the UK alone, the annual value of pollinators to agriculture has been estimated at £440 million. Therefore the loss of pollinators poses a potential threat to food security. However, many pollinator groups, including bees and butterflies, have seen a steady decline in recent years. This is attributed to habitat loss, agricultural intensification and pesticides. This reduction in pollinator diversity and abundance is likely to reduce the efficiency of ecosystem function, as pollination limitation can reduce fruit production and seed set in flowering crops and wild flowers.
A successful management strategy to increase pollinator numbers must consider all aspects of its life cycle, including both nesting and foraging habitats. Bumblebees require nectar and pollen resources throughout the flowering season (spring, summer and autumn) as well as suitable undisturbed nesting sites to establish a successful colony, butterflies and hoverflies require suitable plants to lay eggs and provide food for larvae. Actions like the introduction of ‘bee hotels’ or planting diverse flowering mixes into agricultural landscapes, may help to mitigate against the decline of pollinator species, help to increase crop yield, sustain wild flower numbers and provide a food resource for larger animals such as birds.
Dan Carpenter (Natural History Museum/ Earthworm Society of Britain): Earthworm biodiversity and functioning (PDF 381KB)
Earthworms are an important part of the soil ecosystem. They play a vital role in the decomposition process, incorporating organic matter into the soil. Earthworm burrows and casts have an impact on soil structure by producing stable aggregates, creating pores and mixing soil horizons. So important is their role in creating and maintaining soil structures that they have been called ‘ecosystem engineers’. Earthworm activity is vital for creating healthy and fertile soils. The talk outlines the diversity of earthworms in UK soils, the ecological roles of different species and suggests strategies for managing soils to protect/enhance earthworm populations and maintain soil health/fertility.
Iain Tolhurst (Tolhurst Organic Produce): Functional biodiversity in practice (PDF 2.5MB)
The development of bio-diversity on farms is often seen as an additional activity to the main farm role of food/crop production. It tends to be something that producers do on odd corners and unusable areas of land, the odd beetle bank here and nesting box there- a bolt-on extra, something to do when all else is done. There is another and I would say easier way to achieve a far more comprehensive approach to the creation of a viable and creative bio-diversity and that is to consider it as a part of the “systems approach” to agriculture. This is an integrative method whereby bio-diversity becomes the main driver of the production system, fruit and vegetables become the by- product of bio-diversity. This approach starts from the soil up with the development of a soil rich in microbes, rotation design, green manures, choice of suitable cropping and appropriate compost applications. Above ground, as well as cropping there will be beetle banks, field margins, hedgerows and managed wildlife habitats. The whole system allows healthy cropping with few pest problems, working with nature rather than trying to dominate it.