Dairy production systems (DPS) across Europe face significant sustainability challenges. Among these, the need to reduce greenhouse gas (GHG) emissions and nitrogen (N) losses is becoming increasingly crucial due to binding international agreements and legal requirements. However, given the diversity of DPS, the successful reduction of these negative impacts needs from tailored strategies and adapted evaluation frameworks that jointly consider the climatic conditions, farm characteristics and practices in an integrated manner. In this line, two articles led by Xabier Díaz de Otálora Aguirre (ATB, Germany) and with the participation of the DairyMix consortium, were published assessing the influence of farm diversity on emissions and tackling the adapted mitigation of DPS emissions from a context-specific perspective. In this two-fold approach, the SIMSDAIRY deterministic whole-farm modelling approach was used to estimate the GHG emissions and N losses from a wide range of DPS across Europe. This model captures the effect of different farm management choices and site-specific conditions on nutrient cycling and emissions from other components of a dairy farm.
The influence of different management practices and structural characteristics on N and GHG emission sources was assessed using exploratory multivariate data analysis. In this way, quantitative and qualitative variables could be jointly assessed. This analysis showed how intensive farms in temperate climates have lower enteric emissions but higher manure management emissions. Furthermore, semi-extensive farms in cooler climates exhibit higher N losses and GHG emissions due to intensive mineral fertilisation and slurry application.
Once the structural features, management practices, and characteristics that contribute most to the GHG emissions and nutrient losses were determined, the individual and combined effect of the adapted application of six emission mitigation practices in across European DPS was analysed. These practices include (i) reducing crude protein content in the concentrate, (ii) increasing the amount of concentrate on the diet, (iii) implementing anaerobic digestion plants, (iv) shallow slurry injection, (v) rigid slurry covers and (vi) the substitution of urea as mineral fertiliser.
The application of adapted mitigation options showed how reducing the crude protein content of the purchased fraction of the diet was an adequate strategy to reduce the GHG and N emission intensity in all DPS. Furthermore, implementing an anaerobic digestion plant reduced GHG emissions in all tested case studies while increasing the intensity of nitrogen emissions, mainly when slurry was applied using broadcast. Regarding the productivity increase, contrasting effects were observed amongst the case studies modelled. Moreover, shallow slurry injection effectively mitigated the intensity of nitrogen losses from the fields due to solid reductions in ammonia volatilisation. When substituting urea with ammonium nitrate as mineral fertiliser, site-specific conditions affected the mitigation potential, discouraging its application on sandy-loam soils. Rigid slurry covers effectively reduced the storage-related nitrogen emissions intensity while showing a minor effect on total greenhouse gas emission intensity. In addition, our results provide novel evidence regarding the advantages of cumulative implementation of adapted mitigation options to offset the negative trade-offs of single-option applications (i.e. slurry covers or anaerobic digestion and slurry injection).
These recently published studies provide a deeper understanding of how emission mitigation strategies can be tailored to European DPS. The combination of whole-farm modelling approaches with multivariate statistical methods offers a valuable framework for designing and implementing specific practices that promote sustainability and nutrient circularity in DPS. These results not only help reduce the environmental impact of dairy production but also promote more sustainable and efficient agricultural practices, aligning with the European Union’s sustainability goals.
The paper titled “Influence of farm diversity on nitrogen and greenhouse gas emission sources from key European dairy cattle systems: A step towards emission mitigation and nutrient circularity”, can be accessed at the following link: https://doi.org/10.1016/j.agsy.2024.103902
Whereas the paper, titled “Modelling the effect of context‑specific greenhouse gas and nitrogen emission mitigation options in key European dairy farming systems”, is available at the following link: https://doi.org/10.1007/s13593-023-00940-6.
