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DiverseForages for Livestock Production
BY CHRIS REYNOLDS,
PROFESSOR OF ANIMAL & DAIRY SCIENCE (UNIVERSITY OF READING) DIRECTOR OF CEDAR (THE CENTRE FOR DAIRY RESEARCH)
The DiverseForages Project is a five-year project funded by the Sustainable Agriculture Research and Innovation Club (SARIC), led by the University of Reading in collaboration with Duchy College, Rothamsted North Wyke, and Cotswold Seeds. The overall aim of the project is:
PROJECT OVERVIEW
Three forage mixtures comprising six, twelve, or seventeen species were established in Autumn of 2016 and compared to N fertilised PRG at multiple research sites and farms over three growing seasons (2017-2019). All three multi-species treatments included PRG, timothy, red and white clover, and plantain and chicory. Treatment mixtures received no N fertilizer for the duration of the study. Measurements included:
• Biomass yield, sward botanical and nutrient composition, and soil properties in a longterm replicated agronomy study at four sites in the South of England.
• A comparison of agronomic performance of mixtures sown at dry and wet sites.
• An assessment of the performance of the two most complex mixtures on ten participatory farms.
• A two-year evaluation of forage nutritional value, including measurements of digestibility, nitrogen use efficiency, methane emission, and growth rate of grazing cattle in 2018 and 2019.
1. For the agronomy trials, there was large variation in the species present across sites, sampling times within the growing season, and years of the study, in spite of the use of the same seed mixtures for establishment at each site. The number of unsown species (weeds) was greatest in PRG, which received no herbicide during the study. Overall, the PRG control with N fertiliser produced more biomass in year one, but the multispecies swards with no N fertiliser were as productive as PRG receiving N in year two, and produced more forage biomass than PRG in year three. Years two and three were relatively dry years, which limited PRG growth, and legumes in the multispecies swards were more established in years two and three, which made up for the lack of N fertiliser.
Compared to the PRG receiving N fertilizer, the multispecies swards were lower in crude protein, water soluble carbohydrates, and neutral detergent fibre, and higher in ash concentration. There were no effects of treatments on soil structural assessments or composition, but the number of earthworms present was greater for the multispecies treatments.
2. There was no effect of treatments on growth rates of steers and their average daily gain.
Digestibility of diet dry matter and fibre was not affected by treatment, but protein digestibility was greater for PRG compared to the multispecies swards. Methane emission per kg forage consumed was higher for PRG, but similar for the multispecies sward treatments.
Overall, the results show that established multispecies swards containing legumes produced forage yields that were comparable to, or greater than, PRG receiving 250 kg N/ ha. Greater earthworm populations were present after three years of multispecies sward establishment. Although PRG receiving N fertiliser had higher crude protein concentration at harvest, the overall digestibility of the multispecies swards was comparable to PRG and also supported comparable growth rates in grazing cattle. In addition to the increased biodiversity observed with multispecies swards, and the benefits of withdrawing mineral N fertiliser and associated reductions in greenhouse gas emissions (embedded carbon for fertiliser synthesis and transport and nitrous oxide emissions following application), steers consuming multispecies swards produced less methane per unit forage consumed, further lowering the net carbon footprint of production.
Acceptable yields & drought resilience Increased biodiversity Increased earthworm populations Lower protein content at harvest BUT Comparable digestibility & growth rates No requirement for mineral N fertiliser Reductions in methane production by grazing cattle
Professor Chris Reynolds recently spoke about the findings from the SARIC project at the British
Grassland Society Research Conference.
Research posters and recordings from the conference can accessed on the BGS website. For more information: SARIC DiverseForages project
Long-Term Effects of Reduced Protein Supply
Contact information
Prof. Chris Reynolds, Director of CEDAR Research c.k.reynolds@reading.ac.uk | 0118 378 4684
