Award details

Diverse forage mixtures to optimise ruminant animal production, nutrient use efficiency, environmental impact, biodiversity, and resilience

Reference	BB/N004353/1
Principal Investigator / Supervisor	Professor Christopher Reynolds
Co-Investigators / Co-Supervisors	Dr Kirsty Joan Hammond, Dr David Humphries, Dr Hannah Jones, Professor Martin Lukac
Institution	University of Reading
Department	Sch of Agriculture Policy and Dev
Funding type	Research
Value (£)	838,456
Status	Completed
Type	Research Grant
Start date	01/04/2016
End date	31/03/2021
Duration	60 months

Abstract

In the face of climate change and unpredictable seasonal events, mineral nitrogen (N) inputs must decrease, and forage yield and quality must be more resilient to variable weather patterns. There is concern about the poor persistency of ryegrass and the need for improved herbage quality and quantity in variable climates. There is increasing awareness of the role of species-rich plant communities in reducing environmental impact and having positive consequences for agricultural productivity. Diverse plant communities are expected to utilise available resources more efficiently than monocultures due to species-niche complementarity and positive interspecific interactions. Manipulation of plant species richness found that the most diverse mixtures, on average, achieved a yield benefit of +77%, compared with monocultures. Further, reliance on mineral N inputs has been reduced by exploitation of N fixation from legumes, with grass-legume mixtures containing 40-60% legume and receiving 50 or 150 kg/ha/yr fertiliser N achieving similar yields as grass monocultures fertilised with 450 kg N/ha/yr. The objective of greater sustainability, biodiversity, and resilience of livestock production will be achieved here through the harnessing of forage mixtures that have the capability to be more productive under variable climates, require less N fertiliser due to reliance on N-fixation capabilities, and contribute to greater N use efficiency at animal and farm scales, compared to swards typically grazed in the UK. Forage treatments will be based on agricultural and environmental requirements, and developed and performance tested in different areas of the UK. Agronomic characterisation, utilisation and feed value for livestock, on-farm uptake and performance, and resilience and recovery to drought and water stressors will be investigated. Information will be integrated into models to provide farm and national scale assessments for efficient, productive and sustainable agriculture.

Summary

Growth and supply of pasture is the most cost effective way to feed sheep and cattle. Pasture is comprised mainly of ryegrass, or ryegrass mixed with white or red clover, with the total amount of pasture produced dependent on the climate, management, soil, and amount of fertiliser used. Ryegrass and clover thrive in a moist, cool environment, but these 'optimal' conditions are occurring less often due to an unpredictable and changing climate. Both drought and soil water-logging reduce the amount of forage that can be grown, which affects farm productivity and, ultimately, increases the cost of producing UK 'home grown' milk and meat. There are a number of essential nutrients that plants need for growth. Most of these nutrients are supplied through the soil but others such as nitrogen (N) are lacking for many plants and therefore need to be added in the form of a mineral fertiliser. Mineral fertilisers are expensive to produce through reliance on oil, and are detrimental to the environment through their production and contribution to soil nitrous oxide emissions and pollution of waterways. A solution to these concerns is through the use of a greater diversity or variety of forage plants. The more plant species in an ecosystem the healthier, more robust and resilient it is to changing environments. Diverse mixtures containing drought-tolerant and flood-tolerant plants can provide a source of high quality feed in the face of erratic weather patterns, above and beyond that of typical climate-specific pastures. These diverse plants include legumes which reduce the need for mineral fertilisers because they provide an excellent source of N for pastures due to their ability to convert or 'fix' unusable atmospheric N gas. As a result this improves soil fertility, forage production, and enables N to be better utilised at the animal and farm scales. This, combined with reduced methane emissions from livestock fed diverse forage mixtures can reduce the carbon footprint of milk and meat production. These benefits however, can only be achieved with greater farm uptake of such forages. The ultimate aim of this project is to achieve high yields of good quality forage for livestock production whilst having a positive and long term impact on the environment. We envisage that this can be achieved by utilising diverse forage mixtures that have the potential to be productive during more challenging climatic scenarios, as well as improving N use efficiency, compared to ryegrass or ryegrass/clover pastures. The project will include a series of agronomic and 'on farm' evaluations of the performance of diverse forage mixtures, formulated for fertility building, resilience, and drought tolerance. Diverse mixture formulations will be based on our previous research and industry needs, and compared to conventional ryegrass and fertiliser. The forage treatments will be compared across a range of environments over multiple seasons in the southern UK and their feeding value for livestock and effects on N utilisation will be measured in a series of nutrition studies with growing cattle. The results will be integrated using existing farm scale models of nutrient balance and ecosystems services to determine the overall benefits of diverse swards in terms of nutrient cycling and the wider ecosystem, and the results disseminated through participatory workshops. The research outcomes from this project will deliver rapid, high impact results for increasing on-farm sustainability in terms of livestock production systems, soils and the environment.

Impact Summary

Agriculture in the UK accounts for 75% of UK food consumption and 71% of land use. Of that land use, 71% (50% of UK land) is grassland (Defra, 2013). Ruminants convert human inedible grass and other fibrous materials into high quality foods (milk and meat) for human consumption and thus, ruminant production represents a key agricultural enterprise in the UK, accounting for £9.4 billion of revenue from milk, cattle, and sheep sales in 2013. However, ruminant production accounts for 30% of UK methane emissions and about 40% of UK nitrous oxide emissions and has become increasingly reliant on fertilised mono-culture ryegrass swards in order to maximise production. The ultimate aim of the proposed research is to optimise the balance between forage utilisation for milk or meat production and sustainability in terms of environmental impact, biodiversity, and resilience through the use of swards containing a mixture of diverse forage species. For this proposal 'diverse' swards will be defined as greater than 3 species spanning grasses and legumes; and 'conventional' swards are those with 3 or less species. The results of the project will inform land management practices and the development of systems for productive and efficient use of grasslands for livestock production, as well as sustainable and resilient livestock production systems. The key beneficiaries of this research are: 1.1 Farmers and society: (a) Increased utilisation of legumes in pastures will reduce the cost of soil fertility building and maintenance. It is estimated that the cost of direct mineral nitrogen (N) applications will at least halve when using a diverse ley compared to a ryegrass monoculture. The UK spent £1.6 billion on fertiliser in 2012, and 22% of the cropable area in the UK is temporary grass (Defra, 2013). (b) Improved soil health from greater organic matter content provides an environmental service in terms of greater carbon sequestration and reductions in N and P leaching from agricultural soils (c) The participatory research process defined in WP3 is central to mixture development, wide-scale mixture evaluation and future use. The high level of engagement of farmers will have direct benefits in developing agricultural human and social capital. (d) Economic benefits for farmers that utilise diverse forage mixtures in grassland-based farming systems and are able to sustain food production in times of climatic stress that would otherwise limit forage production. 1.2 Wider society and UK economy: (a) Reduced use of N fertiliser and reduced manure N excretion by animals (due to more efficient forage N utilisation) reduces nitrate, ammonia, and nitrous oxide emissions attributable to ruminant agriculture, thereby reducing eutrophication of water and greenhouse gas emissions. Effects of tannins and other bioactive compounds in diverse forage swards on enteric methane emissions (Hammond et al., 2014) will also reduce the UK greenhouse gas inventory. (b) The UK economy: increased resilience of forage production and efficiency of production will improve the profitability of the UK ruminant livestock sector with consequent benefits further down the food chain. 1.3 UK agriculture and environment: diverse legume leys provide an abundant food resource for pollinator species for the duration of the growing season (Brown, 2013). This enhances the ecosystem service of pollination. Use of drought and flood resistant diverse mixtures for grassland-based agriculture will be resilient to climatic extremes and enable sustainable food production. 1.4 Seed producers and suppliers: an increased market value of diverse forage species is predicted. Seed valued at circa £250/ha, if it were drilled on a mere 1% of total temporary pasture in the UK would be valued at £3.4 million.

Committee	Research Committee A (Animal disease, health and welfare)
Research Topics	Crop Science, Plant Science, Soil Science, Systems Biology
Research Priority	X – Research Priority information not available
Research Initiative	Sustainable Agriculture Research and Innovation Club (SARIC) [2014]
Funding Scheme	X – not Funded via a specific Funding Scheme

Associated awards:

BB/N004191/1 Diverse forage mixtures to optimise ruminant animal production, nutrient use efficiency, environmental impact, biodiversity and resilience

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