Pedoclimatic, knowledge and management factors drive European soybean and faba bean yields

Abstract

The low usage of grain legumes in European cropping systems is often attributed to yield gaps due to limiting pedoclimatic conditions, sub-optimal management practices, and farmers’ limited experience and knowledge in growing these crops. The relative contributions of these factors to current grain legume yield gaps at European scale and, in particular, the difference between yields achieved by experienced farmers and those achieved by novices remain unknown. We therefore explored the relationship between yields and these different factors, to identify areas where farmers require more support to close the yield gaps in grain legume production. To this purpose, we conducted a large-scale online farmer survey in nine European countries with a focus on soybean and faba bean. For both crops, classification and regression tree analysis identified country of production as the primary explanatory variable of yield variation and confirmed the hypothesis that greater experience and knowledge is associated with higher yields. However, the effect of several factors differed between the crops, showing the need for legume-specific strategies. Experience and knowledge were particularly important for soybean, although also relevant for faba bean in low-yielding environments. Other important factors identified to determine yield for soybean included farm specialization, agroclimatic zone, the number of years growing grain legumes and the size of farmland, while for faba bean these important factors were pest management and perceived soil fertility. Farmers highlighted drought, weed infestation, and soil characteristics as having critical impacts on yields for both crops, as well as inoculation and irrigation for soybean. Both soybean and faba bean growers emphasized the need for more information on plant protection and cultivar selection. The results indicate the potential to increase legume yields by supporting farmers in the first years of growing grain legumes, especially for crops that have a shorter history in Europe such as soybean.

Open Access funding enabled and organized by Projekt DEAL. The research leading to these results received funding from Horizon Europe (Grants 031B0807B, 101059824), the Ministry of Agriculture and Forestry of Finland (MMM) (Grant 272/03.01.02/2019 (VN/4475/2020)), the Department for Environment, Food and Rural Affairs (Defra) of the UK (Contract No CH0214), the German Federal Ministry of Education and Research (BMBF) (Grant 031B0807B), the French National Research Agency (ANR), the French National Research Institute for Agriculture, Food and the Environment (INRAE), the Polish National Centre for Research and Development (NCBR) (Grant SUSCROP/I/LegumeGap/01/2019), the Netherlands Organization for Scientific Research (NWO) (Grant ALW.FACCE.23), the Spanish State Research Agency of the Ministry of Economy, Industry and Competitiveness (MINECO-AEI) (Grant MCIN/AEI/https://doi.org/10.13039/501100011033 co-funded by the European Union Grant PCI2019-103597) (Grant MICIN/AEI/https://doi.org/10.13039/501100011033 co-funded by the European Social Fund), the Latvian Ministry of Agriculture, Academy of Agricultural and Forest Sciences (LAASF), and the Scottish Government Strategic Research Fund. Daniel Plaza-Bonilla is Ramón y Cajal fellow (RYC-2018–024536-I) co-funded by the Spanish State Research Agency (MICIN/AEI/https://doi.org/10.13039/501100011033) and the European Social Fund. Co-funding to Ioanna Mouratiadou came from the VALPRO Path EU project “new VALue landscapes for plant PROtein Pathways” (Grant 101059824). Cairistiona Topp and Christine Watson received support from the Scottish Government Strategic Research Fund. HORIZON EUROPE Framework Programme ,Grant 031B0807B