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Abstract

Cover crops which support the overwintering of farmland birds need to be optimised in terms of: 1. seed availability, 2. insect biomass, 3. structure. This project aims to look at the role hulled wheat may play within such cover crops. Crop trials are currently being undertaken to look at the performance and productivity of different hulled wheat strains with a view to investigating incorporation of hulled wheat into cover crops and the impact of these cover crops on farmland bird populations.

Description

Farmland bird populations have suffered significant declines since the 1970’s when agricultural intensification led to a reduction in the availability of invertebrates and seeds due to: (i) a loss of mixed farming; (ii) increased use and efficiency of pesticides; and (iii) changes in crops grown/rotation and grassland management. Drainage and increased field sizes also led to the loss of habitat suitable for nesting and wetland areas important for soil invertebrates.

Whilst invertebrates are a key part of these birds’ diets, seed is also a significant component during the winter. There is evidence that a shortage of available seeds over winter due to the use of herbicides is a significant contributory factor in farmland bird population decline (Newton, 2022). This is further impacted upon by climate change which causes extreme and unpredictable weather patterns.

There are 3 options available to support wild farmland birds including: 1. habitat creation as part of local nature recovery which takes time and is not always appropriate with the demands of national food security; 2. year-round supplementary feeding which requires consistent financial and man power resources and encourages pests; and 3. establishing bird seed mix margins (AB9) which provide food throughout the year.

Bird seed cover crops provide the most immediate and sustainable option to support farmland bird populations. However, the period of seed provision needs to be extended through the winter. One way this may be achieved is to consider including hulled wheats (sometimes referred to as ‘ancient grains’) in AB9 mixes which retain their seeds for longer providing a slow release of seed into the environment as the husk degenerates over time (Longin et al, 2016). Commercially available hulled wheats that may be used for this include: Spelt (Triticum aestivum spelta); Emmer (Triticum turgidum) and Einkorn (Triticum monococcum). In order to create a mosaic of cover crops across a diverse farm scape other hulled wheat such as Macha (Triticum aestivum macha) and Timopheev’s wheat (Triticum timopheevii) may also be worth considering due to their tolerance of poor soil and waterlogging. Finally, Rivet Wheat (Triticum turgidum) a non–hulled species of wheat may assist with longevity of seed provision due to its barbed awns that initially deter birds but fall off as the plant ripens. Additional advantages using these species of wheat is their reported resilience to weather extremes and need for up to 50-25% less nitrogen.

The objectives of this study will be to run experimental trials to establish (i) the rate at which different hulled wheat species release seeds into the environment over winter; (ii) the added nutritional value of these species to the farmed landscape; (iii) whether their inclusion into AB9 seed mixes has an effect on the growth of the other species in these mixes; and (iv) the effect of these species on biodiversity, soil health and carbon emissions. Finally, the benefits of incorporating these species of wheat into bird seed mixes on the abundance and diversity of farmland bird populations will be assessed; and the methods used during implementation of this agri-environment strategy will be evaluated in terms of their sustainability.

Initial crop trials with each species of wheat will be set up in randomised and replicated plots to determine patterns of growth, yield; and requirements in terms of: IPM, fertiliser and herbicides/weeding. Their compatibility with the other species of plant within the bird seed mix will be assessed and the nutritional value of the seeds will be tested. Their resilience to extremes of weather will be monitored individually. Appropriate bird seed mixes with combinations of each of the wheat species will be designed and trialled. Each novel mix will be assessed overall for its resilience in terms of climate, disease and its contribution to soil health, biodiversity and GHG emissions.

Cover crops using those mixes identified as optimal for all the attributes identified above will be planted across the Harper Adams Farm using a stratified sampling strategy which relates to existing annual Breeding Bird Surveys. A number of other farms in different areas of the country with varying soil and climate types may also be used. Monthly bird surveys to assess abundance of farmland bird indicator species will be conducted to determine the impact of these cover crops on bird populations. Finally, the effects of these trialled bird seed mixes on the reproductive success of yellowhammers (Emberiza citrinella), a key farmland bird indicator species in decline (see: McHugh et al, 2022) but present on Harper Adams farmland will be measured in collaboration with the BTO.

 

References

Longin, C.F.H., Ziegler, J., Schweiggert, R., Koehler, P., Carle, R., and Wurschum, T. (2016) ‘Comparative study of hulled (Einkorn, Emmer and Spelt) and naked wheats (Durum and Bread Wheat): Agronomic Performance and Quality Traits. Crop Science 56(1) pp. 302-311

 

McHugh, N.M., White, P.J.C., Moreby, S., Szczur, J., Stoate C., Leather, S.R., Holland, J.M. (2022) ‘Linking agri-environment scheme habitat area, predation and the abundance of chick invertebrate prey to the nesting success of a declining farmland bird. Ecological Solutions and Evidence (3) 2

Newton, I. (2022) ‘The recent declines of farmland bird populations in Britain: an appraisal of causal factors and conservation actions’ Ibis 146 (4) pp. 579-600.