The climate impact and land use of cultivated meat: Evaluating agricultural feedstock production

Account for crop rotation and land use practices: xj � L � CRj ð4Þ where: • xj is the land used for crop j. • L is the total available land. • CRj is the crop rotation factor for crop j, representing the maximum proportion of land that can be used for this crop to ensure sustainable rotation. Account for total land use constraint: X j2Cropsxj � L ð5Þ The model aims to identify the optimal combination of activities x that maximizes the total production of CM medium M, while complying with the available resources and crop rotation restrictions. The model’s outcome serves to calculate and compare the area of land (in square meters) required per kilogram of produced CM compared to pork meat, or conversely, the yield of CM compared to pork meat (in kilograms) per square meter of land. This provides a comparable metric for assessing the efficiency and sustainability of the CM production process in southern Germany as the case study region. We used Microsoft Excel’s Solver Add-In for linear programming. Solver’s optimization function balanced CM production nutrient requirements with crop area allocation, consider- ing crop rotation constraints. This linear programming approach provided insights into which crops were most limiting and which nutrients were in surplus or deficit. 3.3 Technical inventory and background: Linear programming for CM Our study applies strict crop rotation restrictions to mirror realistic farming practices and ensure sustainable soil management in southern Germany. Regardless of farm structure or

land ownership, these restrictions limit the share of each crop to maintain long-term yield lev- els. We examined protein plants (soybean, lupine, field bean, pea, winter rapeseed, and sun- flower) and starch plants (grain maize, winter wheat, rye, triticale, winter barley, oat, and potato). Table 1 provides crop yield statistics, showing that southern Germany’s yields are above the world average [83]. Soybeans are traditionally grown in warm regions, but advances in plant breeding and agri- cultural technology have made it possible to grow adapted varieties in more northern regions. In southern Germany, soybean farming increases crop diversity and reduces reliance on imported soybeans for livestock feed [85]. Challenges such as pest and disease risks and limited domestic market demand must be considered. We applied a soybean restriction to a maximum of 50% of the land area. A two- year maize-soy rotation system, proven feasible in Canada and the US Midwest [86–88], is assumed for southern Germany. Summer crops are limited to no more than two-thirds of the land area. Grain maize is capped at 50%, while sunflower and potato each have a 20% cap. Winter crops also follow the two-thirds limit for the total farm area, with specific restrictions: wheat at 33.33%, rye at 50%, triticale at 33.33%, winter barley at 33.33%, oats at 25%, and rapeseed at 20%. These rotation limits are based on data from Diercks & Heitefuss (1990) [89], Kolbe (2021) [84], and Reckling et al. (2016) [90] (Table 2). PLOS ONE Evaluating agricultural feedstock for cultivated meat

PLOS ONE | https://doi.org/10.1371/journal.pone.0316480 January 22, 2025 9 / 27