Mid-Term Effects of Conservative Soil Management and Fruit-Zone Early Leaf Removal Treatments on the Performance of Nerello Mascalese (Vitis vinifera L.) Grapes on Mount Etna (Southern Italy)

Elisabetta Nicolosi,Valeria Iovino,Alberto Palliotti,Gaetano Distefano,Giuseppina Las Casas,Mario Di Guardo,Stefano La Malfa,Filippo Ferlito,Alessandra Gentile

doi:10.3390/agronomy11061070

Abstract

The aim of this study was to analyze the mid-term influence of minimum tillage (MT) combined with early leaf removal (ELR) on the performance of the black grapevine variety Nerello Mascalese (Vitis vinifera L.). The research was carried out from 2015 to 2018 in a vineyard located in the Mount Etna area, East Sicily, Southern Italy. An average of about 8000 cm2 of leaves were removed from the ELR vines, corresponding to a canopy defoliation of 44% in 2017 and 30% in 2018. As for the stem water potential of both primary and lateral leaves, ELR-MT treatment showed the best performance (up to −0.4 MPa) among the four combinations. In 2017, no differences in yield/vine were found among treatments, whereas in 2018 the yield was significantly lower in ELR treatments. Among the different treatments performed, the ELR-MT showed the best results both in terms of physiological plant parameters (water status and photosynthetic activity) and fruit quality (higher concentration of sugars and total anthocyanins and polyphenols). ELR-MT treatment is also associated with a lower incidence of tillage operations from four to only one per year (−60–70 h/ha). In contrast to what was observed in the first 3 years of application (i.e., from 2015 to 2017), yield was heavily penalized during the fourth year of application (2018), probably due to the excessive depletion of nutritional reserves, the reduction of bud fertility and the unfavorable meteorological condition. For these reasons, the ELR-MT combination might require an interruption every 2–3 years of application.

Highlights

The Etna area (East Sicily, Southern Italy) is characterized by a wide variety of microclimate and soil composition; such environmental characteristics, coupled with adequate management practices, have a strong impact on grape and wine properties
Conservative soil management reduces the energetic costs [7,8] related to field maintenance, and have beneficial effects on root growth, resulting in an improved soil volume explored by the plants [9,10]
This study was conducted in an area that is often characterized by a rainy period starting from October until March, and a dry period from the last days of the spring until the end of summer, in which rains may occur in the last phases of grape ripening, increasing the incidence and severity of rots

Summary

Introduction

The Etna area (East Sicily, Southern Italy) is characterized by a wide variety of microclimate and soil composition; such environmental characteristics, coupled with adequate management practices, have a strong impact on grape and wine properties. For its sustainability and to ensure optimal must composition, grape production requires the application of both conservative soil practices and the use of effective canopy management strategies. Conservative soil management practices such as zero or minimum tillage reduce erosion rates and moisture losses and increase organic matter content [4,5], with a positive effect on the yield and fruit quality traits [6]. Among the conservative practices (i.e., zero tillage, minimum tillage, mulch tillage and cover crops [11]), minimum tillage is a valid alternative to conventional tillage to control weed competition, vine vigor and bud fertility [6], avoiding the excessive water consumption observed with other techniques, such as the use of cover crops [12]. In conservative tillage systems (i.e., zero and minimum) the soil density in the untilled layers increases, but a greater biological density of the untilled layer may be counterbalanced by an increase in biological macroporosity and pore continuity [14]

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Discussion

Conclusion