Transport of Nitrate and Chloride in Variably Saturated Porous Media

González-Delgado, Amir M.; Shukla, Manoj K.

doi:10.1061/(asce)ir.1943-4774.0000725

Cited by 10 publications

(10 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…, 1 is the pore-connectivity parameter (unitless), and K s is the saturated hydraulic conductivity (cm d -1 ). Root water uptake was simulated according to Feddes et al (1978), with the sink term (S r ) accounting only for the water stress. The uncompensated root water uptake model was used (with a w c value of 1) (Šimůnek and Hopmans, 2009).…”

Section: Numerical Modelingmentioning

confidence: 99%

“…The longitudinal dispersivity was considered equal to one-tenth of the profile depth for all soil depth intervals (Cote et al, 2003;Hanson et al, 2006;Phogat et al, 2012). Molecular diffusion was neglected because it was considered negligible relative to hydrodynamic dispersion (Deb et al, 2015;González-Delgado and Shukla, 2014). The first-order decay coefficient m a for urea was considered to be 0.38 d -1 for all soil depth intervals (Hanson et al, 2006).…”

Section: Measurements and Model Inputsmentioning

confidence: 99%

“…rigated fields contaminates groundwater (Böhlke, 2002;Cepuder and Shukla, 2002) because NO 3 -N is a weakly absorbed ion that moves quickly through soil (González-Delgado and Shukla, 2014;Spalding and Exner, 1993). Leaching of NO 3 -N to groundwater is affected by type of irrigation system (Sharma et al, 2012a) and by soil texture, and it can be high in arid and semiarid areas such as southern New Mexico, especially in surface-irrigated areas with sandier soils (Al-Jamal et al, 1997;Sharma et al, 2012b).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Numerical Modeling of Nitrate in a Flood‐Irrigated Pecan Orchard

Mokari

Shukla

Šimůnek

et al. 2019

Soil Science Soc of Amer J

Self Cite

View full text Add to dashboard Cite

Soil Physics & Hydrology pecan [(Carya illinoinensis (Wangenh.) k. koch] is an important specialty crop in New Mexico. This research quantifies soil water and soil nitrate-nitrogen (NO 3-N) (mg L −1 of soil) variations with depth, root NO 3-N (kg ha −1) uptake, and NO 3-N (kg ha −1) balance for the 100-cm soil profile during two growing seasons in a flood-irrigated pecan orchard. Nitrate-nitrogen was determined six times during the growing seasons of 2015 and 2016. The HYDrUs-1D model was used to optimize the water flow parameters using measured volumetric soil water content (q). Model calibration and validation for NO 3-N included the optimization of reaction parameters for nitrification and denitrification of each soil layer. The results showed that the model simulated q well (0.44 £ d [index of agreement] £ 0.73) at different depths during both calibration (2009) and validation (2010) periods. generally, HYDrUs-1D simulated soil profile NO 3-N concentrations that were correlated with measurements at all depths during both years. Total root NO 3-N uptake showed a significant increase of 72% in 2016 compared with 2015. The NO 3-N balance showed that ?40% of applied NO 3-N per year was denitrified, which was the main contributor to the NO 3-N loss from the soil profile during both years. Nitrate-nitrogen leaching below the soil profile was 32 and 26% of applied NO 3-N in 2015 and 2016, respectively. The fertigation rate was much higher than the plant demand during both years, and it should be decreased to reduce NO 3-N losses.

show abstract

Section: Numerical Modelingmentioning

confidence: 99%

Section: Measurements and Model Inputsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Numerical Modeling of Nitrate in a Flood‐Irrigated Pecan Orchard

Mokari

Shukla

Šimůnek

et al. 2019

Soil Science Soc of Amer J

Self Cite

View full text Add to dashboard Cite

show abstract

“…Soil at the study site is classified as Glendale (fine-silty, mixed, calcareous, thermic typic Torrifluvents) and Harkey (coarse-silty, mixed, calcareous, thermic typic Torrifluvents). The study region is arid, with an average air temperature of 17.7°C and annual precipitation of 29.7 cm (Gile et al 1981). The field was under onionsudan (Sorghum sudanense) grass rotation for several years.…”

Section: Field Descriptionmentioning

confidence: 99%

“…Apart from the economic considerations of nutrient losses, fertilization practices in irrigated agriculture directly and indirectly affect the composition of groundwater recharge and aquifer biogeochemistry (Böhlke 2002). The highly soluble complex ion NO − 3 , which is only weakly adsorbed by particles in most soils, is a common contaminant of groundwater (Spalding and Exner 1993;González-Delgado and Shukla 2014). Groundwater contamination by NO − 3 leaching continues to be of great agroenvironmental concern in climatic regions where irrigated agriculture is dominating and excessive N fertilizers are applied to arable soils every year.…”

Section: Introductionmentioning

confidence: 99%

Numerical Evaluation of Nitrate Distributions in the Onion Root Zone under Conventional Furrow Fertigation

et al. 2016

Self Cite

View full text Add to dashboard Cite

HYDRUS (2D/3D) model was used to simulate spatial and temporal distributions of nitrate-nitrogen (NO 3 -N) within and below the onion root zone under conventional furrow fertigation with the urea-ammonium-nitrate (UAN) liquid fertilizer. The simulated water contents in the furrow irrigated onion field agreed well with the measurements. Simulations produced similar patterns of the measured NO 3 -N concentration profiles throughout the growing season. NO 3 -N concentrations remained higher and accumulation of NO 3 -N was observed within the root zone. Higher NO 3 -N within the root zone was dependent on the rate of the UAN fertilizer application, quantity of NO 3 -N removed by root uptake, and NO 3 -N drainage fluxes below the root zone. Simulations also suggested that NO 3 -N below the root zone during different growth stages remained much higher than a recommended (for drinking water) standard concentration level (10 mg L −1 ). This resulted in higher NO 3 -N drainage fluxes, particularly during the fertigation events between the establishment and vegetative growth stages. This indicates the need to apply most fertigation events at an early stage of bulb formation to provide the maximum NO 3 -N demands by onions and to reduce potential NO 3 -N leaching.

show abstract