Aurélie Metay

Changing the soil surface management in vineyards: Immediate and delayed effects on the growth and yield of grapevine

In a changing context, farmers adapt their cropping systems and, in this respect, the response time of the soil-crop system (changes in the soil resources and in the grapevine vegetative or reproductive development) has to be considered to maintain its agronomic performances. This is particularly true for perennial crops such as grapevine. This paper aims to analyse the short- and long-term effects of changes in soil surface management on grapevine performances. A vineyard in which bare soil inter-rows had been compared with a tall fescue intercrop since 2002 had each of these treatments split into two in 2007, with half of the intercrop being ploughed in and half of the bare soil being sown with fescue, resulting in four treatments whose effects were studied in 2008–2009. Grapevine growth, yield formation and grape quality were assessed. After intercrop destruction, grapevine vegetative growth was enhanced by the mineralization of organic matter from the first year, whereas after intercrop introduction, the competition for soil resources affected growth only in the second year. The grape yield depended on the number of bunches, elaborated the year before. One year after the change in soil surface management, the ranking of yield was as follows: permanent intercrop < intercrop destroyed < intercrop introduced < bare soil. The second year, this ranking altered (still in relation to the number of bunches) to: intercrop introduced < permanent intercrop < bare soil = intercrop destroyed. This study shows that the response times of the processes of grapevine vegetative growth and yield formation to a change in the cropping system vary from one to two years, and therefore, have to be considered carefully to manage the cropping system well.

Nitrogen supply controls vegetative growth, biomass and nitrogen allocation for grapevine (cv. Shiraz) grown in pots

Maintaining grapevine productivity with limited inputs is crucial in Mediterranean areas. Apart from water, nitrogen (N) is also an important limiting factor in grape growing. The effects of N deficiency on grapevine growth were investigated in this study. Two-year-old Vitis vinifera L.cv. Shiraz plants grafted on 110 R were grown in pots placed outside and exposed to various N supplies (0, 0.6, 1.2, 2.4 and 12g plant-1) under well-watered conditions. At veraison, plants were harvested and organs separately dried, weighed and analysed for N. During plant growth, the length of the primary and secondary axes and the number of leaves on them were recorded. The N content of leaves was also analysed at three phenological stages (flowering, bunch closure and veraison). All growth processes were inhibited by N deficiency in an intensity-dependent manner. Quantitative relationships with N supply were established. Vegetative growth responded negatively to N stress when comparing control N supply with no N supply: primary axis elongation (-61%), leaf emergence on the primary axis (-47%), leaf emergence on the secondary axis (-94%) and lamina area expansion (-45%). Significant differences on the plant N status were observed from flowering onwards which might be useful for managing fertilisation.

A plant trait-based response-and-effect framework to assess vineyard inter-row soil management

Abstract Biodiversity impacts ecosystem properties and the ecosystem services provided by those ecosystems. As a result, promoting plant diversity in agricultural systems has been a key issue in agriculture over recent years. In this context, weeds have an important role in maintaining field biodiversity, when it is balanced with their potential negative impact on crop production. Functional trait diversity, rather than the diversity of species per se, is a facet of biodiversity most directly related to species and community responses to management practices, with subsequent consequences for ecosystem services. Trait-based approaches, originally developed in the field of comparative ecology, allowed the description of weed species responses to management practices in annual crop systems. Here, we aimed to extend the trait-based approach to the spontaneous vegetation of vineyards. First, we propose a brief summary of current knowledge about weed communities in vineyards. Then we show how the relationships between management practices, weeds and grape vines can be translated into a response–effect framework: soil management practices (tillage, cover crops, spontaneous vegetation) can be considered as environmental filters that determine the composition and structure of vegetation, which, in turn, modify grapevine growth conditions in the vineyard. Finally, we tested this framework in a Mediterranean vineyard where, for 2 years, we characterized the responses of different components of weed communities (taxonomic and functional composition) in three inter-row management practices (tillage, cover crops and mowing spontaneous vegetation) and their effects on several grapevine processes (vine yield, vine leaf water potential and assimilable nitrogen in must).