Modeling dynamically the management of intercropped vineyards to control the grapevine water status
Résumé
In vineyards, introducing a grass cover as intercrop is a common practice around the world. Indeed, it can provide some ecological services such as mitigation of runoff and erosion, and control of grapevine vegetative development (Battany and Grismer, 2000; Smart et al., 1991). Moreover, it can constitute an interesting alternative to the systematic use of herbicides. However, introducing a new crop makes the system more complex, and farmers have to adapt their way to manage them. In Mediterranean vineyards, a major difficulty is to manage correctly the two crops, to satisfy production and environmental objectives with respect to the competition for soil resources and climate variability. As experiments are time consuming and difficult to carry out in these perennial systems, the use of a modeling approach is more appropriate to test and evaluate different types of intercrop management plans. A recent study showed the difficulty in finding robust management plans over a 30- years period. It can be explained by the fact that they did not manage responsively to observed states of the biophysical system and they did not take into account the high inter- and intra-annual climate variability (Ripoche et al., 2009). This study analyzes the merit of introducing some flexibility in the management of intercrops in vineyards. The investigation relies on a simulation model that reproduces the interactive dynamics of decision-making and biophysical processes. Simulation is used to support the design of more robust management plans enabling control of the grapevine water status in these cropping systems