The SAFFIE Project Report
About this project
The Sustainable Arable Farming For an Improved Environment (SAFFIE) project started in 2002 and experimental work continued until the end of 2006. When the project was conceived, arable farmers needed to optimise inputs and improve efficiency, and the UK was committed to increase biodiversity, especially for farmland birds. The SAFFIE project aimed to reconcile these pressures by developing new crop and margin management techniques for winter cereals and quantifying the associated costs and environmental benefits. The SAFFIE project developed Skylark Plots, confirmed the benefits of adding wildflowers to grass margins, evaluated a range of in crop weed control programmes and tested two margin management techniques (graminicides and scarification) that had potential to create new habitats. The studies quantified: (a) the impact of these techniques on key species of grasses and flowering plants, beetles, bugs, flies, grasshoppers, soil invertebrates, spiders, bees, butterflies and birds; and (b) the costs of the techniques. Key findings included the following. Plants • Weed cover was increased by the use of selective herbicides and this benefited wider biodiversity. Selective herbicide applications in spring left more plant cover than application sequences, benefiting arthropod abundance. However, weed management must be site-specific and this approach is not appropriate where pernicious weeds are common or where there are herbicide resistant weeds.
• Plant species diversity in margins decreased over the five years, regardless of seed mix and treatment.
• Plots sown with a seed mix of fine grasses and wild flowers generally had the greatest abundance of reproductive resources (buds, flowers, seed/fruit) and plots sown with a grass seed mix generally had the lowest values.
• Compared with other margin management treatments, margins scarified in March/April had:
• the greatest percentages of bare ground (21%, compared to 3% with cutting and 4% with graminicide),
• enhanced plant species diversity at some sites,
• plant diversities converging between margins sown with different seed mixes, • lower values of architectural complexity (especially of the dead litter, fine grass and legume components), and
• reduced values of reproductive resources.
• In margins that had an application of a graminicide, plant communities included more sown wildflower species than margins that were scarified or cut. Invertebrates
• The grass seed mix provided a good resource for those invertebrate species that are dependent on sward architectural complexity; however, it is a poor resource for phytophagous species, particularly where their host plants are wildflowers.
• A seed mix of tussocky grasses and wild flowers provided an architecturally complex sward and host plants vital for many invertebrate species. • For a variety of invertebrate taxa there was evidence that abundance and species richness will reach a maximum 2–3 years after margin establishment.
• Sowing a diverse seed mixture of perennial wildflowers was the most effective means of creating foraging habitat for bees and butterflies on arable field 5 margins. Inclusion of forbs in the seed mixture resulted in increases in abundance and diversity of pollen and nectar resources, bumblebees and butterflies.
• Invertebrate species that required either an architecturally complex sward or dense grass responded poorly to scarification, e.g. planthoppers, spiders and Symphyta/ Lepidoptera larvae. In contrast, improved establishment of some wildflower species in response to scarification benefited some phytophagous invertebrates, e.g. weevils and leaf beetles.
• In scarified margins there were fewer species and lower abundances of isopods than in other margins. Species assemblages in the scarified plots consisted of species commonly associated with cropped or exposed habitats. • Graminicide application is a practical option for enhancing the value of the large area of species-poor grass margins for pollinators. Birds
• Creating bare ground and foraging access in wheat crops and field margins were the most important management treatments, and gave a significant (up to 4 fold) increase in bird densities and breeding territories for both field and boundary nesting species. Open ground can be achieved at relatively low cost by scarification in margins, and by creating undrilled patches in winter cereal crops.
• In wheat fields with undrilled patches, skylark territory densities were higher (particularly in the crucial late-season breeding period) and the number of skylark chicks reared was nearly 50% greater than in fields without undrilled patches.
• Wheat sown with wide-spaced rows provided some wildlife benefits (particularly for skylarks) but effects were smaller and less consistent than for crops with undrilled patches.
• For all species and species groups, bird densities and territories were consistently higher (1.3 - 2.8 times) in fields with margins and undrilled patches, than in fields with a conventional crop. This response was consistent also for Farmland Bird Index species and Biodiversity Action Plan species.
• In fields with undrilled patches and un-cropped field margins there were indications that skylarks experienced reduced breeding success and productivity compared with conventionally managed wheat. This was attributed to increased mammalian predator activity. It is recommended that wherever practical undrilled patches should not be situated within 50 m of a margin.
• For birds, margin sward content in terms of the grass/flower mix, was best managed to encourage beetles (especially Carabidae) and spiders (Arachnidae). Costs
• Undrilled patches receiving Defra Entry Level Scheme (ELS) payments had a net benefit to farmers of £7.00 to £8.50 /ha, if made by lifting the drill and there was no additional weed control. If undrilled patches were made using an herbicide after crop emergence, and there was the unlikely need for additional weed control, the net cost to farmers would be £3.50 to £5.00 /ha.
• Field margins established with wild flowers in the seed mixes were ten times more expensive than grass-only seed mixes, and these costs are unlikely to be met by current agri-environment schemes. Higher wheat prices increase costs to the farmer because of greater production loss. Additional agri-environment scheme payments for floristic enhancement of margins are likely to be required if take-up is to be substantially improved. 6 HGCA Project Report No. 416 June 2007 £30.00 The SAFFIE Project Repo