Soil management influences copper export from Northern vineyard plots

Abstract

Hydrological, agronomic and chemical indicators were combined to study the influence of the soil management mode on copper export in Northern vineyard plots (Rouffach, Alsace). An "innovative" mode, involving the conversion to organic farming, with a maintenance of mechanical soil, and a "classical" management mode, with standard soil maintenance and chemical weeding, were compared during two contrasting vine-growing seasons (April to October 2015 and 2016). The monthly water reserve state of the soil was lower than the useful reserve, thereby limiting vertical flows in both management modes. Grass cover on one out of two inter-rows limited runoff volumes to a maximum runoff coefficient of up to 1.4% for the two vine-growing seasons. The seasonal export of copper occurred mainly by surface runoff. Mass export of solid-bound copper contributed to more than 95% of total copper export from the vineyard plots. Plowing work on the "innovative" plot a few days before a most intense storm event of the 2015 season resulted in a mass export of copper accounting for 99% of the total mass exported during the vine-growing season. Destructuring of surface soil layer and tillage type preceding a stormy period strongly influence water flows as well as export of both dissolved and solid-bound copper.