Lixiviação de nitratos em diferentes tipos de solos e sistemas de produção agrícola na Zona Vulnerável a Nitratos de Esposende-Vila do Conde

Nitrate leaching in different soils types and agricultural production systems in the Nitrate Vulnerable Zone of Esposende-Vila do Conde

Abstract

The Vulnerable Zone nº 1 - Free Aquifer between Esposende and Vila do Conde was created in 1997, through Ordinance nº. 1037/1997 of October 1, and appears on the list of Nitrate Vulnerable Zones to (NVZ) as one of the nine currently existing in Mainland Portugal, designated as Vulnerable Zone of Esposende-Vila do Conde.

Since 2007, the Direção Regional de Agricultura e Pescas do Norte (DRAP Norte) has been monitoring this ZVN with a follow-up methodology that involves data collection, analysis, rural extension and training of technicians and farmers as a means of supporting implementation of the Vulnerable Zones Action Program (Ordinance nº 259/2012, of 28 August).

Based on this methodology, this work aimed to analyze and disseminate the results obtained in 3,764 water analyzes carried out between 2008-2022 in 12 fixed points where the amount of nitrates (NO₃^-) is monitored every two weeks, having as main differentiators factors the soils types of and the agricultural production system.

The results obtained point to a downward trend in average annual concentrations, with significant annual fluctuations (by soil type, location and production system) and higher concentrations in arenosols with intensive horticulture.