Influence on wine biogenic amine composition of modifications to soil N availability and grapevine N by cover crops.

BACKGROUND: Vineyard soil management can modify the nitrogen soil availability and, therefore, grape amino acid content. These compounds are precursors of biogenic amines, which have negative effects on wine quality and human health. The objective was to study whether the effect of conventional tillage and two cover crops (barley and clover) on grapevine nitrogen status could be related to wine biogenic amines. Over 4 years, soil NO3- -N, nitrogen content in leaf and wine biogenic amine concentration were determined. RESULTS: Barley reduced soil NO3- -N availability and clover increased it. In 2011, at bloom, nitrogen content decreased with barley treatment in both blade and petiole. In 2012, nitrogen content in both leaf tissues at bloom was greater with clover than with tillage and barley treatments. Also, total biogenic amines decreased in barley with respect to tillage and clover treatments. There were correlations between some individual and total biogenic amine concentrations with respect to nitrogen content in leaf tissues. CONCLUSION: Wine biogenic amine concentration can be affected by the grapevine nitrogen status, provoked by changes in the soil NO3- -N availability with both cover crop treatments. © 2017 Society of Chemical Industry.

Evolution of some physical properties related to soil quality in the degraded ecosystems of "raña" formations from SW Spain.

The dynamics of some physical properties of the soil: bulk density, porosity and percentage of water stable aggregates, which usually are taken as indicators for evaluation of soil quality, have been studied on the flat surfaces of the Cañamero's "raña" formation (Cáceres, SW Spain). The study shows a high relationship between all these physical soil parameters, the degradation level of the natural vegetation, and years of the soil under tillage. As the deterioration of the natural soil increases the bulk density of the fine earth is increased, diminishing porosity, field capacity moisture content, percentage of water stable aggregates in soil and water infiltration.