Importance of soil fertility for climate-resilient cropping systems: The farmer's perspective

Healthy and productive agricultural soils are the basis for global food security as they are a prerequisite for yield-stable cropping systems under climate change. Despite the expansion of agricultural research activities in this area through field experiments, lab analyses, and modelling frameworks, current empirical insights from farming practice on a more national scale are still rare. For this reason, the agronomic importance of soil fertility for farming practice was the focus of this nationwide empirical study conducted in Germany (winter/spring 2022) with a total sample size of 585. The views and needs of 370 farmers and 215 agricultural institutionalists were evaluated, i.a., regarding the importance of soil fertility and related soil properties, as well as preferred agronomic management strategies and needs for the promotion of soil fertility. The results showed that most farmers and institutionalists consider soil fertility to be very important. Moreover, it was emphasized that the importance of this factor will increase in the future due to changing climatic conditions (e.g., heat/drought stress) and the need for more sustainable land use including the protection of biodiversity. The main motivations for agronomic investments in greater soil fertility were improving the climate resilience and yield stability of cropping systems. In this context, the top soil properties of interest were ranked by the respondents as follows: (1) water storage capacity, (2) rootability, (3) biological activity, and (4) water infiltration rate. To promote soil fertility, farmers mainly considered catch cropping, diversified crop rotations with a positive humus balance, and year-round ground plant cover/mulch as the most useful agronomic measures. In terms of methods for the assessment of soil fertility, soil structure analyses, biological indicators, yield/biomass production, soil nutrient analyses, and field methods were most important, whereas sensor systems and apps/digital tools were of minor importance. For the future improvement of soil fertility promotion in farming practice, simple indicators and reference values for assessing soil fertility as well as 'workshops, field days, and field schools' for training aspects were suggested by the participants. Overall, there were few differences between the perceptions of farmers and agricultural institutionalists. Both groups pointed out the need for improved communication between politics, science, and practice such that agriculture can respond more quickly to changing climatic conditions in the future.