Under-vine Management Impacts Soil Properties and Leachate Composition in a New York State Vineyard

Abstract

Four under-vine management treatments were established in 2011 in a Vitis vinifera L. ‘Cabernet Franc’ vineyard in the Finger Lakes region of New York: cultivation (CULT), native vegetation (NV), white clover Trifolium repens L. (WC), and glyphosate herbicide (GLY) as the control. Previously installed drainage lysimeters were used to monitor nutrient and pesticide concentrations in leachate water samples. Differences in the physical structure of soils among treatments were only observed in the 4th year of the study when the top 6 cm of CULT soils had greater bulk density than the other treatments, and less porosity and available water capacity than WC soils. WC soils had 17% greater organic matter than CULT soils, and 46% greater aggregate stability than GLY soils. Soil microbial respiration was generally greater in NV and WC treatments than GLY and CULT. Dissolved organic carbon (DOC) leachate concentrations were greater in GLY and CULT compared with NV and WC, having annual mean DOC leachate concentrations as much as 36% greater than the cover crop samples. Mean annual total nitrogen (TN) leachate concentrations of CULT and NV were less than GLY and WC samples by as much as 86%. In 2012, GLY soils leached greater concentrations of imidacloprid insecticide and more imidacloprid metabolites than the other three treatments, with the proportion of samples testing positive for measurable concentrations of imidacloprid or imidacloprid metabolites at least five times greater in GLY than the other treatments. Cumulatively, these factors demonstrate the potential of under-vine cover crops to maintain soil quality and decrease the leaching of nutrients and agrochemicals in vineyards in comparison with conventional practices.