Speaker
Description
Context description and research question: An increasing number of farmers are considering the impact of conservation practices on soil health to guide sustainable management of vineyards. Understanding impacts of soil management on soil organic carbon (SOC) is one lever for adoption of agroecological practice with potential to help maintain or improve soil health while building SOC stocks to mitigate climate change (Amelung et al., 2020). Despite the potential of perennial cropping systems as C sinks, a major part of the world’s agricultural landscapes remains dominated by specialized practices and, although winegrowers understand how to improve SOC, they face real or perceived challenges in adopting soil conservation practices. In this study, we analyzed extension specialists’ perceptions of the challenges and opportunities to maintain or increase SOC in vineyard soils in two main wine producers, in France and in the United States. Our goal was to characterize current practices and better understand the challenges at the farm level (structural barriers, trade-offs, conflicts of interest, education and training) regulating adoption of practices favorable to SOC. The 4 contexts are USA-cool, USA-warm, F-cool and F-warm vineyards.
Method and theoretical background: To identify universal principles in vineyard soil management, we conducted exploratory semi-structured interviews in both warm and cool climate areas in France and in United States, to get some universal practices and challenges, not depending on climate variation. The results could then, be transposed to any other vineyard. We identified 16 extension specialists in each country; eight in cool climates and eight in warm climates. Our hypothesis was that the structure of the supply chain in each of the four regions (France/warm, France/cool, U.S./warm, U.S./cool) would impact barriers and levers for adoption.
Results and discussion: We found seven SOC-favorable practices already managed in France and USA, both in cool and warm climates. All extension specialists reported that cover crop, organic fertilization, tillage reduction, grazing, agroforestry, mulching and herbicide use reduction are already implemented by some winegrowers and should be further incentivized. We found details about cover crop characteristics including the surface area of cover crop, the diversification of spontaneous and sown the species in cover crop, and turning over the cover crop. Using compost or returning pruning residues to the soil were highlighted by interviewees as important practices for organic fertilization. We found economic, agronomic, educational, conflict of interest and structural challenges to practice adoption. 69% of the extension specialists mentioned the cost of the practice as the first challenge to adoption SOC-favorable practice, and the potential negative impacts of yield. An agronomic challenge identified specifically was concerns over competition of cover crop with vine vigor. Education and training of winegrowers needed included knowledge to implement the practices at the field scale and systems redesign at the farm scale. Conflicts of interest included potential food safety issues associated with livestock grazing, particularly in table grape production. A first structural barrier identified included climate of the location of the vineyard for competition for water and nitrogen, which is a big issue with the actual change of the climate. A second structural barrier identified included planting density for agroforestry in Protected Designation vineyards and availability of organic fertilizers next to the farm. Greater emphasis on addressing the challenges to adoption of SOC-favorable practices is urgently needed to inform national and regional agricultural policies in both countries.
| Keywords | Soil organic carbon sustainability, practices, climate zone, extension perception, vineyard, country |
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