Green manuring in horizontally terraced vineyards: A new approach

Abstract

A number of studies in viticulture dealt with cover crops cultivated on the entire surface of every second alleyway, limiting spring soil trafficability to the non-cultivated ones. In order to guarantee soil trafficability of every alleyway in horizontally terraced vineyards, this study investigates a new approach to cultivate green manure cover crops in the central 60 cm-stripe of every alleyway.

The objectives of our study were to evaluate 1) the degree of soil fertility and grape quality improvement resulting from the cultivation of green manure crops compared to control cover crops with permanent resident species; and 2) the effects of an additional fertilization of cover crops with liquid manure.

Experiments were conducted from 2009 to 2014 in Northern Italy. Soil tilling for seed-bed preparation and sowing of cover crops was carried out annually after harvest. The control treatment was mowed two to tree times a year. Soil humus and plant available nitrogen were determined in 2009 and 2014. Effects on grapes and vines were monitored in 2014 (°Babo, pH, titrable acidity, yeast assimilable nitrogen, berry mineral nitrogen, leaf nutrients at bloom and veraison, and leaf chlorophyll).

Compared to control cover crops both green manure treatments noticeably increased humus content and plant available nitrogen. Addition of liquid manure resulted in a significantly higher availability of soil nitrogen. Furthermore, increments in yeast assimilable nitrogen- and leaf chlorophyll content were observed due to improved soil characteristics. Other grape and vine parameters analyzed were not affected by the treatments.

Cultivation of a 60 cm green manure strip in the centre of every alleyway had a positive impact on soil and grape characteristics. This new approach combines in situ grown green manure plants with secure trafficability of every alleyway in horizontally terraced vineyards.