Mixenable Deliverable D5.1: Development of the IAT and ORFEE models for simulating mixed livestock farms

Summary

Climate change and depletion of natural resources calls for a more sober and carbon neutral agriculture. Farmers are also challenged by climate change with more frequent and severe droughts and heat waves in an economic context often difficult. Mixed farming systems are gaining interest both as a risk management strategy and to apply agroecological principles. Diversity in organic farming systems is particularly important since those farms have limited access to external inputs and more frequently use direct marketing. According to Dumont et al. (2020), diversity of system components and interactions among these components can increase productivity, resource-use efficiency and farm resilience. The complementarities between livestock and crops offer levers to close local nutrient cycles, reduce GHG emissions intensities and increase carbon storage. The complementarity between two animal species appears as a promising leverage to use more efficient plant resources and to stabilize farm performance which has been little studied until now (Martin et al. 2020). In the MixEnable projet, we want to analyse how organic mixed livestock farming systems are resilient and sustainable and how their farming systems could be adapted to reduce their vulnerability.
Modelling offers a comprehensive way to understand complex farms in which exogenous and endogenous factors affect farm sustainability and robustness. Compared with real farm data analysis, modelling offers the possibility to do virtual experiments to test and compare strategies under modified climate or economic conditions and to disentangle the processes involved. Few farm models target organic systems (Olesen et al. 2006; Kerselaers et al. 2007) or offer the possibility to simulate different livestock species (Kerselaers et al. 2007; Lengers et al. 2014) and none of them provide enough flexibility to explore the variety of management options in a mixed livestock farm. Two existing models (Lisson et al. 2010; Mosnier et al. 2017a) have useful characteristics and could be further developed for modelling organic mixed livestock farms. The IAT model (Lisson et al. 2010) was developed to be used in a participatory way with smallholder crop-livestock farmers. The model of Mosnier et al. (2017) is more detailed, and better suited to desktop analysis. In the deliverable, we first compare the main attribute of each model relative to the needs of the project and then present the main developments made in Orfee that has been eventually used in MixEnable.