A Spatially Distributed, Physically-Based Modeling Approach for Estimating Agricultural Nitrate Leaching to Groundwater

Abstract

Nitrogen-nitrate, while being fundamental for crop production, is of particular concern in the agricultural sector, as it can easily leach to the water table, worsening groundwater quality. Numerical models and Geographic Information System may support the estimation of nitrate leaching rates in space and time, to support sustainable agricultural management practices. In this paper, we present a module for the simulation of the processes involved in the nitrogen cycle in the unsaturated zone, including nitrate leaching. This module was developed taking steps from the ANIMO and EPIC model frameworks and coupled to the hydrological models integrated within the FREEWAT platform. As such, the nitrogen cycle module was then included in the FREEWAT platform. The developed module and the coupling approach were tested using a simple synthetic application, where we simulated nitrate leaching through the unsaturated zone for a sunflower crop irrigated district during a dry year. The results of the simulation allow the estimation of daily nitrate concentration values at the water table. These spatially distributed values may then be further used as input concentration in models for simulating solute transport in aquifers.

Assessing Nitrate Contamination Risks in Groundwater: A Machine Learning Approach

“…In the index techniques, experts suggest a weight to each parameter in associated methods based on their knowledge. These techniques include the DRAV model [22], Susceptibility Index (SI) technique [23], GOD technique [24], ANIMO and EPIC models [25], and the DRASTIC model [2]. The interpolation methods utilize sensors and devices and indicator kriging (IK) based on geostatistical procedures using the kriging interpolation algorithm [26][27][28][29].…”

“…Rahmati et al [54] used three advanced ML techniques, including K-nearest neighbor algorithm, random forest, and support-vector machines (SVM) to spatially model groundwater nitrate concentrations in Iran. De Filippis et al [25] used a spatially distributed, physically-based modeling approach for estimating agricultural nitrate leaching into groundwater in Italy. Sajedi-Hosseini et al [15] also used three ML techniques, including multivariate discriminant analysis (MDA), SVM, and boosted regression trees (BRT), for the probability of nitrate groundwater contamination occurrence in Iran.…”

Predicted and Measured Concentration of Pharmaceuticals in Surface Water of Areas with Increasing Anthropic Pressure: A Case Study in the Coastal Area of Central Italy

“…Main natural processes are weathering of bedrock minerals, evapotranspiration, deposition of dust and salt, leaching of organic matter and nutrients from soil, hydrological factors leading to run-off, and biological processes. Human activities, such as discharging treated or untreated sewage, may determine point and nonpoint sources of pollution in both rural and urban areas, releasing, e.g., nitrates [6,7]; metals such as mercury, lead, and cadmium [8]; organics such as pesticides [9]; and pharmaceutical compounds (PhCs) [10][11][12][13]. Several physical, biological, and chemical methods were developed and applied for the removal of inorganic and organic compounds from water.…”

An Integrated Framework to Assess the Environmental and Economic Impact of Fertilizer Restrictions in a Nitrate-Contaminated Aquifer

“…Nitrate is generally considered one of the most widespread and persistent pollutants found in groundwater, originating from multiple nitrogen sources, primarily related to human activities, and to a lesser extent, to natural processes [1][2][3][4][5]. Anthropogenic sources mainly include agricultural activities such as fertilizer and manure applications and animal feedlot operations, as well as industrial and sewage discharges.…”

“…Anthropogenic sources mainly include agricultural activities such as fertilizer and manure applications and animal feedlot operations, as well as industrial and sewage discharges. Natural sources like decomposing organic matter or atmospheric nitrogen deposition also contribute to nitrate occurrence in groundwater, but anthropogenic sources tend to have a more pronounced impact due to their scale and intensity [1,[6][7][8][9][10]. Among various human nitrate sources, agricultural activities, and especially the use of nitrogen-rich fertilizers for enhancing crop productivity, have been recognized as the main cause of groundwater nitrate contamination worldwide, posing a serious threat to rural areas [8,[11][12][13][14].…”