A simplified modelling approach for pesticide transport in a tile-drained field: The PESTDRAIN model

Abstract

International audienceThe paper presents a simplified model called PESTDRAIN. It simulates pesticide transport in a subsurface tile-drained field. It computes surface runoff and tile-drainage flow rates, along with the associated pesticide concentrations, with a variable event-driven time step. PESTDRAIN consists of three coupled modules: SIDRA, SIRUP and SILASOL. SIDRA and SIRUP are the water flow simulation modules in the saturated and unsaturated zones, respectively. SIDRA follows a simplified physically based approach while SIRUP follows a conceptual capacitive approach. SILASOL is the solute transport module for both the saturated and unsaturated zones and is based on transfer functions. It includes simple representations of adsorption and degradation of pesticides. PESTDRAIN was tested on field data sets collected for three drainage seasons at the La Jaillière experimental site in north-western France, for the wheat herbicides isoproturon (IPU) and diflufenican (DFF). After model calibration, relative errors for drainage and surface runoff flows over the season were 14% and 4%, respectively, and the Nash–Sutcliffe efficiency coefficient (Neff) value for drainage discharge was 0.58. A fair reproduction of a high temporal resolution IPU concentration data set in drainage discharge was also obtained (Neff=0.28). For the validation data sets, PESTDRAIN was able to simulate accurately drainage discharge with Nash–Sutcliffe efficiency coefficients of 0.57 and 0.69. The global Neff was 0.44 for all flow-weighted average weekly concentrations in drainage. Relative errors for the pesticide losses were 2.5% and 35% (IPU), and 60% (DFF). For surface runoff the results were not as accurate, but they remained correct in terms of time location and order of magnitude. Although further validation is necessary with more field data, PESTDRAIN appears as a promising tool for agricultural water management

Artificial Wetland and Forest Buffer Zone: Hydraulic and Tracer Characterization

“…Consequently, a strategy implying two techniques was tested. First, buffer zone inlets were limited by means of polyvinyl chloride pipe measuring 200 mm in diameter, corresponding to a maximum flow rate of approximately 35 L s −1 This made it possible to focus on the first rising part of the floods that may contain the maximum pesticide loads (Branger et al, 2008). Second, the systems were managed by the farmer who was in charge of opening and closing the water entrance in both buffer systems according to pesticide applications.…”

Yayılı Kirleticilerin Havzalardaki Taşınım Süreçleri: Antibiyotikler, Ağır Metaller ve Besi Maddeleri Üzerine Modelleme Yaklaşımları

“…Örneğin, yüzeysel akış ile kirlenme ya da kirleticilerin yer altı suyuna sızmaları farklı modelleme çalışmaları ile simüle edilebilir [49]. Matematiksel modeller 'analitik' ve 'sayısal' olmak üzere iki gruba ayrılırlar.…”

“…Branger ve diğ. [49] toprak drenaj arazisinde pestisit taşınımını simüle edebilmek için PESTDRAIN adında bir model geliştirmişlerdir. Bu model tarımsal su yönetimi için gelecek vadeden bir araç olarak pestisitlerin yüzeysel akış ve drenaj akış hızlarını hem mekansal hem de zamansal değişim gösteren pestisit konsantrasyonlarını dikkate alarak hesaplamaktadır.…”

Toxicity assessment and public policies: An urgent need for research

“…This is very important in the case of pesticides as the risk linked with those highly toxic substances depends mainly on the likelihood of exposure in different compartments of the environment. The coupling of different hydrological models allows to accurately predict pesticide concentration in water (Branger et al, 2009). Such models extended to soil and air are necessary to fully assess the risk associated with the use of pesticides in agriculture.…”