Multicriteria assessment of 11 agroecological viticulture systems during six years

Abstract

Context and purpose of the study. Modern conventional agriculture, including viticulture, relies greatly on the use of chemical inputs, especially synthetic pesticides. However, negative consequences of these practices have included unintentional impacts ranging from water pollution in streams to a decrease in biodiversity, including beneficial pest predators. A shift towards using fewer inputs in agricultural systems is critical to maintain production while improving environmental and social outcomes. As a consequence, more and more recheach is conducted to design, experiment and assess agroecological practical solutions for increasing sustainability of viticulture systems.

Material and methods. To this end, the ECOPHYTO PEPSVI (2013-2018) project designed, experimented, and assessed performances and sustainability of low-input vineyard plots under commercial conditions. Eleven viticulture systems were designed combining technical and management changes to drastically reduce pesticide use. First, the viticulture systems were designed including environmental labels with a gradient from integrated, through organic and biodynamic. Secondly, the viticulture systems inclued soil management practical solutions to avoid using herbicide: cover crop and/or tillage between row and in some systems under vine. Thirdly, fungicide spraying is reduced. Diversity of practical solutions goes from efficiency of spraying, then substitution by biocontrol products, but also to redesign spraying including other practices like addition of essential oils and blowing caps after flowering. Fourthly, some of the viticulture systems included decision aid tools in practical solution to manage the vineyard during the growing-season (e.g. reducing rate of copper and rate of sulfur). And finaly, two of the viticulture systems were redesigned with resistant varieties for both mowdery and downy mildew. The 11 new viticulture systems were ranked according to the “efficiency, substitution, and redesign” (ESR) framework. The sustainability and the performances of viticulture systems were monitored and assessed over six consecutive years. Environmental assessment was done with Treatment Frequency Index. Economical assessment was done with 3 indicators describing yield: calculated yield, ratio of targeted yield and ratio of regional yield and 2 indicators describing the ability of grapes to Protected Designation (PDO) wines powdery mildew and downy mildew severities on grapes at harvest.

Results. This study revealed that pesticide use can be reduced without decreasing absolute value of yield, targeted yield of the winegrower and also yield compared to the regional average of the studied vintage. Thus, low-input plots produced the expected yield for six consecutive years, with acceptable levels of powdery and downy mildew severities for production of PDO wines. This study can encourage the transition towards low-input vineyard systems, through organic and biodynamic managements by providing information to agricultural advisors and reassuring winegrowers who are initially reluctant to shift to such sustainable viticulture systems.