Sustainable agri-food production
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Browsing Sustainable agri-food production by Subject "ammonia"
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Item The Environmental Impact of Lowering Dietary Crude Protein in Finishing Pig Diets—The Effect on Ammonia, Odour and Slurry Production(MDPI, 2022-09-23) Ball, Elizabeth; Smyth, Sam; Beattie, Violet E.; McCracken, Kelvin J.; McCormack, Ursula; Muns, Ramon; Gordon, Fred J.; Bradford, Raymond; Reid, L. Alanna; Magowan, ElizabethExcess nitrogen excretion, ammonia and odour are environmental pollutants associated with pig production. Reducing dietary crude protein (CP) will lower the amount of nitrogen excreted, reducing the potential for ammonia emissions, if diets are adequately formulated to supply amino acids and production performance is maintained. Crude protein content in diets for finishing pigs has been lowered recently, but the quantitative effect of this reduction on ammonia, odour, and slurry output is not well-established. The relationship between ammonia and odour is equivocal, and the effect on slurry production is unclear. The objective of this study was to investigate the effect of lowering dietary CP on ammonia emission, odour emission and slurry output of finishing pigs. Thirty entire boar pigs were individually housed in groups of six, from 10 weeks of age (30 3.0 kg) and offered standard diets. At 75 kg ( 1.5 kg) pigs were assigned to one of three treatment diets; (1) 180 g/kg CP, 11.0 g/kg total lysine (High CP), (2) 150 g/kg CP, 11.1 g/kg total lysine (Medium CP), and (3) 130 g/kg CP, 9.0 g/kg total lysine (Low CP). After three weeks on the experimental diets pigs were moved, six each week, to individual calorimetry chambers to measure ammonia and odour emissions. Pigs were offered treatment diets ad libitum. At the end of the recording period, the pigs were removed from the chamber, weighed and feed disappearance recorded to calculate intake. The slurry in each chamber was collected and analysed. The reduction in CP in the diet from 180 g/kg to 150 g/kg resulted in a 22% reduction in ammonia emissions, and from 180 g/kg to 130 g/kg resulted in a 47% reduction (p < 0.001). Slurry output from pigs offered the 130 g/kg CP diet was reduced by 39% (p < 0.001) and dry matter increased by 35% compared to slurry from pigs offered the 180 g/kg CP diet (p < 0.05). Water usage (p = 0.017), slurry output and nitrogen and phosphate in the slurry (p < 0.05, respectively) were found to decrease linearly with decreasing dietary CP content. There was no significant effect of reducing CP on performance or odour emission but hydrogen sulphide emissions decreased linearly (p < 0.010) with decreasing dietary CP. There was a weak positive relationship between odour emission and ammonia (linear: R2 = 0.25, p = 0.005) with odour emission reduced as ammonia emission reduced. Reducing dietary CP in finishing pig diets could reduce ammonia emissions, water usage and slurry and nutrient output from pig production.Item Greenhouse gas and ammonia emission mitigation priorities for UK policy targets(Higher Education Press, 2023-05-06) Buckingham, Sarah; Topp, Cairistiona F. E.; Smith, Pete; Eory, Vera; Chadwick, David R.; Baxter, Christina K.; Cloy, Joanna M.; Connolly, Shaun; Cooledge, Emily C.; Cowan, Nicholas J.; Drewer, Julia; Duffy, Colm; Fox, Naomi J.; Jebari, Asma; Jenkins, Becky; Krol, Dominika J.; Marsden, Karina A.; McAuliffe, Graham A.; Morrisson, Steven; O'Flaherty, Vincent; Ramsey, Rachael; Richards, Karl G.; Roehe, Rainer; Smith, Jo; Smith, Kate; Takahashi, Taro; Thorman, Rachel E.; Williams, John; Wiltshire, Jeremy; Rees, Robert M.Agriculture is essential for providing food and maintaining food security while concurrently delivering multiple other ecosystem services. However, agricultural systems are generally a net source of greenhouse gases and ammonia. They, therefore, need to substantively contribute to climate change mitigation and net zero ambitions. It is widely acknowledged that there is a need to further reduce and mitigate emissions across sectors, including agriculture to address the climate emergency and emissions gap. This discussion paper outlines a collation of opinions from a range of experts within agricultural research and advisory roles following a greenhouse gas and ammonia emission mitigation workshop held in the UK in March 2022. The meeting identified the top mitigation priorities within the UK’s agricultural sector to achieve reductions in greenhouse gases and ammonia that are compatible with policy targets. In addition, experts provided an overview of what they believe are the key knowledge gaps, future opportunities and co-benefits to mitigation practices as well as indicating the potential barriers to uptake for mitigation scenarios discussed.Item The impact of using novel equations to predict nitrogen excretion and associated emissions from pasture-based beef production systems.(MDPI, 2022-06-14) Angelidis, Angelos E.; McAuliffe, Graham A.; Takahashi, Taro; Crompton, Les; Yan, Tianhai; Reynolds, Christopher K.; Stergiadis, Sokratis; Misselbrook, TomThe excretion of nitrogen (N) in faeces and urine from beef cattle contributes to atmospheric pollution through greenhouse gas and ammonia emissions and eutrophication of land and aquatic habitats through excessive N deposition and nitrate leaching to groundwater. As N excretion by beef cattle is rarely measured directly, it is important to accurately predict losses by utilising a combined knowledge of diet and production parameters so that the effect of dietary changes on the potential environmental impact of beef production systems can be estimated. This study aimed to identify differences between IPCC and more detailed country-specific models in the prediction of N excretion and N losses at a system level and determine how the choice of model influences the interpretation of differences in diet at the system scale. The data used in this study were derived from a farm-scale experimental system consisting of three individual grazing farms, each with a different sward type: a permanent pasture, a high sugar ryegrass monoculture, and a high sugar ryegrass with white clover (~30% groundcover). Data were analysed using a mixed linear model (residual maximum likelihood analysis). The IPCC methods demonstrated significantly lower estimates of N excretion than country-specific models for the first housing period and significantly greater losses for the grazing and second housing periods. The country-specific models enabled prediction of N partitioning to urine and faeces, which is important for estimation of subsequent N losses through the production system, although the models differed in their estimates. Overall, predicted N losses were greater using the IPCC approaches compared to using more detailed country-specific approaches. The outcomes of the present study have highlighted that different models can have a substantial impact on the predicted N outputs and subsequent losses to the environment for pasture-based beef finishing systems, and the importance, therefore, of using appropriate models and parameters