Farm scale impacts of mixed system adoption

Summary

Globally, agriculture produces over 9 billion tonnes of CO2 equivalents annually (FAO, 2020), whilst increased farm specialization in Europe has led to greater separation between crop and livestock production, causing water contamination from excess nitrates and pesticides. Intensive livestock systems, particularly poultry, contribute significantly to environmental degradation through air, water, and soil pollution (Gržinić et al., 2023) and intensive farm systems are a major cause of climate change, pollution, biodiversity loss, and rural social issues (Garrett et al., 2020).
Mixed farming, integrating livestock and crops, has been proposed as a solution to reduce environmental impact by improving nutrient cycling and decreasing reliance on external inputs (Nesme et al., 2015). However, even mixed systems can be intensive, with nutrient flows often oneway, leading to excess nutrients and limited environmental improvement. Organic farming, which restricts external inputs and relies on a more circular system, offers a potential alternative. However, whilst reducing nutrient excesses, it may yield lower output and sometimes higher environmental impacts per product unit (Meier et al., 2015), although recent studies suggest similar impacts per product with lower land use (Hashemi et al., 2024). Agroforestry, incorporating trees alongside crops and/or livestock, is another promising innovation and can provide multiple environmental benefits, including carbon sequestration, nutrient cycling, biodiversity enhancement, and water retention (Sollen-Norrlin et al., 2020). However, the extent of carbon sequestration depends on biomass, and in short-cycle systems, it may only extend the carbon cycle rather than significantly reduce atmospheric CO2 (Quinkenstein et al., 2009).