Procedure for the Measurement of Soil Inputs of Plant-Protection Agents Washed off through Vineyard Canopy by Rainfall

Soil inputs produced by rainfall waters washed off through a Ribeiro vineyard (Galicia, northwestern Spain) confirmed that levels recovered are <5% of the added fungicides. Laboratory studies showed that some fungicides were degraded in the ODS cartridge used for the collection of fungicides washed off by rainfall. Procymidone wash-off data obtained in the vineyard can be explained by a first-order rate mass transfer model. A procedure for the collection of wash-off waters based on octadecylsilane solid phase extraction, followed by an analytical method of reverse-phase liquid chromatography with diode array detection is presented for the evaluation of fungicide inputs into soils after being washed off vineyards by rainfalls. Quality parameters of the analytical method yielded good precision (RSD < 10%) and low detection limits (ranging between 1 and 21 microg/L).