Modeling the water transport and nitrogen dynamics in irrigated salad crops

Lafolie, François; Bruckler, Laurent; Cockborne, A.M. de; Laboucarié, C.

doi:10.1007/s002710050027

Cited by 36 publications

(15 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These solutions require many simplifying assumptions that limit their applicability in practical field conditions. Large differences were observed between the simulated and observed values of water contents (Lafolie et al 1997). Therefore, use of numerical or analytical flow models for design purpose is considered cumbersome and impractical in many situations (Battam et al 2003).…”

Section: Introductionmentioning

confidence: 97%

Modelling of wetting pattern under trickle source in sandy soil of Nirjuli, Arunachal Pradesh (India)

Dabral

Pandey

et al. 2011

Irrig Sci

View full text Add to dashboard Cite

Wetting pattern can be obtained by either direct measurement of soil wetting in field, which is site specific, or by simulation using some models. Use of numerical or analytical flow models for design purpose is considered cumbersome and impractical in many situations. Therefore, present study was undertaken to develop a model for wetting pattern under trickle source in sandy soil of Nirjuli, Arunachal Pradesh. In the present study, the drip irrigation system was operated to record observed wetting front advance (vertical and horizontal) of emitters with flow rates of 2, 4 and 10 l h -1 . A fixed quantity of 4 l of water was applied to the bare dry soil kept in a container of perspex sheet (1 m 9 1 m 9 0.9 m). The wetting front advance was observed just after irrigation and its subsequent redistribution after 1, 2, 4, 6, 9, 12, 15, 18, 24 and 48 h respectively after irrigation. Using Buckingham p theorem, a semi-empirical model was developed to simulate the wetting front pattern under trickle point source at the end of irrigation. Performance of the model just after irrigation was evaluated by comparing estimated values against observed values using F test, t test, ME and RMSE values. The redistribution of the wetting front geometry with respect to elapsed time was modelled with regression analysis using four models viz. linear, logarithmic, exponential and power. Power function was found to be the best fit for horizontal wetting front (W) as well as vertical wetting front advance (Z) based on the highest R 2 value.

show abstract

Section: Introductionmentioning

confidence: 97%

Modelling of wetting pattern under trickle source in sandy soil of Nirjuli, Arunachal Pradesh (India)

Dabral

Pandey

et al. 2011

Irrig Sci

View full text Add to dashboard Cite

show abstract

“…A properly calibrated and validated flow and solute transport model for drip irrigation can provide an understanding of the relationship between the amount and timing of water and nutrient application, crop root uptake, yield and leaching risks (Antonopoulos 2001). Several models have been developed to simulate water flow, solute transport, heat flux, crop water and nutrient uptake and salt dynamics in the soil (Huston and Wagenet 1991;Jarvis 1995;Breve et al 1997;Lafolie et al 1997;Phogat et al 2000). Most of these models describe the early stage of infiltration and provide an estimate of water content behind the wetting front (Clothier and Scotter 1982).…”

Section: Introductionmentioning

confidence: 98%

Modelling soil water and salt dynamics under pulsed and continuous surface drip irrigation of almond and implications of system design

et al. 2011

View full text Add to dashboard Cite

The HYDRUS-2D model was experimentally verified for water and salinity distribution during the profile establishment stage (33 days) of almond under pulsed and continuous drip irrigation. The model simulated values of water content obtained at different lateral distances (0, 20, 40, 60, 100 cm) from a dripper at 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 140 and 160 cm soil depths at different times (5, 12, 19, 26 and 33 days of profile establishment) were compared with neutron probe measured values under both irrigation scenarios. The model closely predicted water content distribution at all distances, times and soil depths as RMSE values ranged between 0.017 and 0.049. The measured mean soil water salinity (ECsw) at 25 cm from the dripper at 30, 60, 90 and 150 cm soil depth also matched well with the predicted values. A correlation of 0.97 in pulsed and 0.98 in continuous drip systems with measured values indicated the model closely predicted total salts in the root zone. Thus, HYDRUS-2D successfully simulated the change in soil water content and soil water salinity in both the wetting pattern and in the flow domain. The initial mean ECsw below the dripper in pulsed (5.25 dSm -1 ) and continuous (6.07 dSm -1 ) irrigations decreased to 1.31 and 1.36 dSm -1 , respectively, showing a respective 75.1 and 77.6% decrease in the initial salinity. The power function [y = ax -b ] best described the mathematical relationship between salt removal from the soil profile as a function of irrigation time under both irrigation scenarios. Contrary to other studies, higher leaching fraction (6.4-43.1%) was recorded in pulsed than continuous (1.1-35.1%) irrigation with the same amount of applied water which was brought about by the variation in initial soil water content and time of irrigation application. It was pertinent to note that a small (0.012) increase in mean antecedent water content (h i ) brought about 8.25-9.06% increase in the leaching fraction during the profile establishment irrespective of the emitter geometry, discharge rate, and irrigation scenario. Under similar h i , water applied at a higher discharge rate (3.876 Lh -1 ) has resulted in slightly higher leaching fraction than at a low discharge rate (1.91 Lh -1 ) under pulsing only owing to the variation in time of irrigation application. The influence of pulsing on soil water content, salinity distribution, and drainage flux vanished completely when irrigation was applied daily on the basis of crop evapotranspiration (ETc) with a suitable leaching fraction. Therefore, antecedent soil water content and scheduling or duration of water application play a significant role in the design of drip irrigation systems for light textured soils. These factors are the major driving force to move water and solutes within the soil profile and may influence the off-site impacts such as drainage flux and pollution of the groundwater.

show abstract

“…Detailed analysis on nitrogen species movement in an unsaturated zone is required to predict the contamination of groundwater, whereas certain nitrogen species such as ammonium-nitrogen (NH 4 -N), nitrite-nitrogen (NO 2 -N), nitrate-nitrogen (NO 3 -N), organic nitrogen and nitrogen gas (N 2 ) are primary nutrients for plant growth. Numerical models and computer simulations are useful tools to forecast and evaluate the complex physical, chemical and biological process associated with nitrogen species transport and transformation in an unsaturated and saturated porous media Selim and Iskandar 1981;Lafolie 1991;Antonopoulos 1993;Tindall et al 1995;Lafolie et al 1997;Lee et al 2006;Zhou et al 2011;Klammler et al 2013). The reduction and transport of various nitrogen species in unsaturated zone are affected by nitrate input, volumetric water content, depth of water table, pH, temperature, microbial activity (Huang et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling of biological clogging on transport of nitrate in an unsaturated porous media

2014

View full text Add to dashboard Cite

In order to better understand nitrogen species transport and transformation in the saturated zone, it is essential to predict the contaminant concentration in the unsaturated zone as the concentration profiles estimated from unsaturated zone forms as the input for estimation of contaminant concentration in the saturated zone. Since the nitrogen transformations occur in the presence of bacteria, there is a need to account the influence of biological clogging to develop comprehensive model of nitrogen species transport. In this study, a one-dimensional numerical model is developed to investigate the nitrogen species transport in an unsaturated porous media along with microbial clogging process. Results suggest that hydraulic conductivity is enhanced initially due to increase in the water content followed by a significant reduction at larger simulation time resulting from bioclogging. As bioclogging mitigates the hydraulic conductivity significantly, a considerable delay is observed in the ammonium nitrogen and nitrate nitrogen transport with reference to the system without bioclogging. In addition, the effect of oxygen mass transfer coefficient on biological clogging was evaluated. Numerical results suggest that as the oxygen mass transfer is decreased the ammonium nitrogen and nitrate nitrogen concentration travels a larger depth. Further numerical results strongly suggest that nitrogen species transport in the unsaturated zone is significantly affected by the presence of biological clogging.

show abstract

Modeling the water transport and nitrogen dynamics in irrigated salad crops

Cited by 36 publications

References 8 publications

Modelling of wetting pattern under trickle source in sandy soil of Nirjuli, Arunachal Pradesh (India)

Modelling of wetting pattern under trickle source in sandy soil of Nirjuli, Arunachal Pradesh (India)

Modelling soil water and salt dynamics under pulsed and continuous surface drip irrigation of almond and implications of system design

Numerical modeling of biological clogging on transport of nitrate in an unsaturated porous media

Contact Info

Product

Resources

About