Partnering for sustainability in agri-food supply chains: the case of Barilla Sustainable Farming in the Po Valley

This is the final version. Available on open access from Springer via the DOI in this recordAvailability of data and materials: Not applicableThe objective of the paper is to understand the process of designing a multi-stakeholder partnership in the adoption of sustainable innovations in value chains. More specifically, the focus is on the design of feasible types of horizontal agreements and contractual formulas to be implemented in the agri-food supply chain in order to introduce sustainable agricultural practices. To this purpose, the Barilla Sustainable Farming initiative, which is currently in the first phase of designing an MSP, is used as a case study.European Union Horizon 202

Deriving simple predictions from complex models to support environmental decision-making

Recent decades have seen great advances in ecological modelling and computing power, enabling ecologists to build increasingly detailed models to more accurately represent ecological systems. To better inform environmental decision-making, it is important that the predictions of these models are expressed in simple ways that are straightforward for stakeholders to comprehend and use. One way to achieve this is to predict threshold values for environmental perturbations (e.g. climate change, habitat modification, food loss, sea level rise) associated with negative impacts on individuals, populations, communities or ecosystems. These thresholds can be used by stakeholders to inform management and policy. In this paper we demonstrate how this approach can use individual-based models of birds, their prey and habitats, to provide the evidence-base for coastal bird conservation and shellfishery management. In particular, we show how such models can be used to identify threshold values for perturbations of food abundance that can impact negatively on bird populations. We highlight how environmental thresholds could be used more widely to inform management of species and habitats under environmental change

Modeling methane fluxes in wetlands with gas-transporting plants. 3. Plot scale.

A process model based on kinetic principles was developed for methane fluxes from wetlands with gas-transporting plants and a fluctuating water table. Water dynamics are modeled with the 1-D Richards equation. For temperature a standard diffusion equation is used. The depth-dependent dynamics of methane, oxygen, molecular nitrogen, carbon dioxide, soil carbon, electron acceptors in oxidized and in reduced form are affected by transport processes and kinetic processes. Modeled transport processes are convection and diffusion in the soil matrix, ebullition, and plant-mediated gas transport. Modeled kinetic processes are carbon mineralization, aerobic respiration, methane production, methane oxidation, electron acceptor reduction, and electron acceptor reoxidation. Concentration gradients around gas-transporting roots in water-saturated soil are accounted for by the models from the two previous papers, ensuring an explicit connection between process knowledge at the kinetic level (millimeter scale) and methane fluxes at the plot scale. We applied the model to a fen, and without any fitting, simulated methane fluxes are within 1 order of magnitude of measured methane fluxes. The seasonal variations however, are much weaker in the simulations compared to the measurements. Simulated methane fluxes are sensitive to several uncertain parameters such as the distribution over depth of carbon mineralization, the total pool size of reduced and oxidized electron acceptors, and the root-shoot ratio. Because of the process-based character of the model it is probable that these sensitivities are present in reality as well, which explains why the measured variability is usually very high. Interestingly, heterogeneities within a rooted soil layer seem to be less important than heterogeneities between different soil layers. This is due to the strong influence of the interaction between water table and profile scale processes on the oxygen input to the system and hence on net methane production. Other existing process models are discussed and compared with the presented model

The production of N2O in Douglas fir litter as affected by anoxic conditions within litter particles and pores

The development of anoxic conditions in forest litter and the relation with nitrous oxide (N2O) production and emission rates are not completely understood. Water content is an important factor in the regulation of N2O production due to its effect on the development of anoxic conditions. A combination of simulation modeling and incubation experiments was used to study (1) O2 concentrations in water and organic matter at various water saturation fractions of inter-particle pores in Douglas fir litter (F2 horizon), (2) the relationship between N2O production and moisture content of litter and (3) to test whether diffusion constraints of nitrate (NO3¿) could have explained measured N2O production rates within litter fragments. Model simulations showed that the occurrence of high N2O production rates in samples with extremely high water contents coincided with the development of anoxic conditions in water-filled inter-particle pores. Measured N2O production rates started to increase exponentially after 1¿2 days in glucose-amended samples, during which substantial microbial growth was established. For these latter samples model simulations showed that the increase in O2 consumption due to microbial growth lead to anoxic conditions in water-filled pores at locations which were far from the O2 saturated air-filled pores. It was concluded that anoxic conditions in water-filled pores was the crucial factor for the development of high N2O production rates. Diffusion limitation of NO3¿ and glucose were estimated to be negligible in the highly fragmented litter material used. The occurrence of diffusion limitation depended on litter particle size, the NO3¿ reduction potential and the NO3¿ concentration. Therefore, diffusion limitation together with N2O production in litter cannot be neglected under field conditions with a low NO3¿ concentration or a high NO3¿ reduction potential

Buoyancy-driven flow in a peat moss layer as a mechanism for solute transport

Transport of nutrients, CO(2), methane, and oxygen plays an important ecological role at the surface of wetland ecosystems. A possibly important transport mechanism in a water-saturated peat moss layer (usually Sphagnum cuspidatum) is nocturnal buoyancy flow, the downward flow of relatively cold surface water, and the upward flow of warm water induced by nocturnal cooling. Mathematical stability analysis showed that buoyancy flow occurs in a cooling porous layer if the system's Rayleigh number (Ra) exceeds 25. For a temperature difference of 10 K between day and night, a typical Ra value for a peat moss layer is 80, which leads to quickly developing buoyancy cells. Numerical simulation demonstrated that fluid flow leads to a considerable mixing of water. Temperature measurements in a cylindrical peat sample of 50-cm height and 35-cm diameter were in agreement with the theoretical results. The nocturnal flow and the associated mixing of the water represent a mechanism for solute transport in water-saturated parts of peat land and in other types of terrestrializing vegetation. This mechanism may be particularly important in continental wetlands, where Ra values in summer are often much larger than the threshold for fluid flow