Towards a regional mapping of vine water status based on crowdsourcing observations

Monitoring vine water status is a major challenge for vineyard management because it influences both yield and harvest quality. It is also a challenge at the regional scale for identifying periods of high-water restriction or zones regularly impacted by water stress and changes of these impacts over the years. This information is interesting for defining collective strategies, anticipating harvest logistic issues or applying for irrigation authorisation. At this spatial scale, existing tools and methods for monitoring vine water status are few and often require strong assumptions and/or parameters to be defined exhaustively (e.g. water balance model). This paper proposes to consider a collaborative collection of observations by winegrowers and wine industry stakeholders (crowdsourcing) as an interesting alternative. Indeed, it allows the collection of a large number of field observations while pooling the collection effort. However, the feasibility of such a project and its interest in monitoring vine water status at regional scale has never been tested. The objective of the article is to explore the possibility of making a regional map of vine water status based on crowdsourcing observations. It is based on the free mobile application ApeX-Vigne, which allows the collection of observations of vine shoot growth. This information is easy to collect and can be considered, under certain conditions, as a proxy for vine water status. Nearly 5,000 observations were collected by winegrowers and wine industry stakeholders during 2019, 2020 and 2021 seasons. Vine shoot growth maps were derived from this dataset at regional scale and its ability to monitor temporal evolution of these maps was studied. This article also proposes an analysis of the factors that favoured the number of observations collected. These results open up new perspectives for monitoring vine water status at the regional scale, they also provide references for other crowdsourcing projects in viticulture.