Estimating Nitrate Leaching to Groundwater from Orchards: Comparing Crop Nitrogen Excess, Deep Vadose Zone Data‐Driven Estimates, and HYDRUS Modeling

Baram, Shahar; Couvreur, Valentin; Harter, Thomas; Read, Marsha; Brown, Patrick H.; Kandelous, Maziar M.; Smart, David R.; Hopmans, Jan W.

doi:10.2136/vzj2016.07.0061

Cited by 66 publications

(44 citation statements)

References 50 publications

(77 reference statements)

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“…A recent study by Baram et al. [27] estimated leaching loss of 80-240 kg N/ha y from an almond (Prunus dulcis) orchard irrigated with micro-sprinklers, and most of the loss occurred early in the growing season (February-May), when urea-ammonium nitrate fertilizer was commonly applied to wet soil. Thus, high-frequency DI and fertigation could potentially reduce fertilizer losses and protect groundwater quality [17,28].…”

Section: Introductionmentioning

confidence: 99%

Carbon and Nitrogen Dynamics Affected by Drip Irrigation Methods and Fertilization Practices in a Pomegranate Orchard

et al. 2019

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Knowledge of carbon (C) and nitrogen (N) dynamics under different irrigation practices in pomegranate orchards is novel and essential to develop sustainable production systems. The aim of this research was to determine the effect of high-frequency drip irrigation and different rates of N fertilizer on C and N distribution in the soil and N uptake by pomegranate fruit and leaves. The main treatments were surface drip irrigation (DI) and subsurface drip irrigation (SDI), and the sub-treatments used were three initial N rates (N1, N2, and N3). As trees grew larger, the N application rate increased. From 2013-2015, trees received the following rates of N: 62-113 (N1), 166-263 (N2), or 244-342 kg/ha (N3). Soil and leaf total C (TC) and N (TN), soil dissolved organic C (DOC), soil nitrate (NO 3 − ), and total N uptake by fruit were evaluated between 2012 and 2015. Soil samples were collected to 120 cm depth at 15 cm increments. DI resulted in higher concentrations of TN, TC, NO 3 − , and DOC in the upper 75 cm depth than SDI. The N3 treatment resulted in higher concentrations of TN, TC, NO 3 − , and DOC under both DI and SDI. Neither DI nor SDI at the N1 or N2 levels increased TN and NO 3 − concentrations at 105-120 cm soil depth, indicating reduced leaching risk using high-frequency drip irrigation. Higher N uptake by fruit was observed in SDI than in DI in 2014 and 2015, and in N2 and N3 treatments compared with N1 in 2013 and 2014. The data indicate that the application rate at 166-263 kg/ha (N2) provided sufficient N for a 4-6-year-old pomegranate orchard and that high-frequency SDI is a promising technology for achieving higher N use efficiency and minimizing leaching loss of NO 3 − and DOC.

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Section: Introductionmentioning

confidence: 99%

Carbon and Nitrogen Dynamics Affected by Drip Irrigation Methods and Fertilization Practices in a Pomegranate Orchard

et al. 2019

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“…Numerous studies of N budget analysis in agricultural fields [25][26][27][28][29][30] concluded that the nitrate leaching could be substantial and depends mainly on the rate of applied fertilizer, source of N, soil types, and the amount of rainfall water.Nitrogen is present in the soil in nine different forms, including intermediaries of subsequent transformations, corresponding to different oxidative states [31,32]. HYDRUS software (developed by [33]) is widely used as a finite element model for simulating the movement of water, N transport, and the transformation process in variably saturated soil [34][35][36][37]. The governing convection-dispersion solute transport equations are written in a relatively general form by including provisions for non-linear, non-equilibrium reactions between the solid and liquid phases and linear equilibrium reactions between the liquid and gaseous phases [36].…”

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confidence: 99%

Effect of Deficit Irrigation on Nitrogen Uptake of Sunflower in the Low Desert Region of California

Eltarabily

Burke

Bali

2019

Water

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Nitrogen (N) accounts for more than 80% of the total mineral nutrients absorbed by plants and it is the most widely limiting element for crop production, particularly under water deficit conditions. For a comprehensive understanding of sunflower Helianthus annuus N uptake under deficit irrigation conditions, experimental and numerical simulation studies were conducted for full (100% ET C ) and deficit (65% ET C ) irrigation practices under the semi-arid conditions of the Imperial Valley, California, USA. Plants were established with overhead sprinkler irrigation before transitioning to subsurface drip irrigation (SDI). Based on pre-plant soil N testing, 39 kg ha −1 of N and 78 kg ha −1 of P were applied as a pre-plant dry fertilizer in the form of monoammonium phosphate (MAP) and an additional application of 33 kg ha −1 of N from urea ammonium nitrate (UAN-32) liquid fertilizer was made during the growing season. Soil samples at 15-cm depth increments to 1.2 m (8 layers, 15 cm each) were collected prior to planting and at three additional time points from two locations each in the full and deficit irrigation treatments. We used HYDRUS/2D for the simulation in this study and the model was calibrated for the soil moisture parameters (θ s and θ r ), the rate constant factors of nitrification (the sensitive parameter) in the liquid and solid states (µ w,3 , and µ s,3 ). The HYDRUS model predicted cumulative root water uptake fluxes of 533 mm and 337 mm for the 100% ET C and 65% ET C , respectively. The simulated cumulative drainage depths were 23.7 mm and 20.4 mm for the 100% ET C and 65% ET C which represented only 4% and 5% of the applied irrigation water, respectively. The soil wetting profile after SDI irrigation was mostly around emitters for the last four SDI irrigation events, while the maximum values of soil moisture in the top 30 cm of the soil profile were 0.262 cm 3 cm −3 and 0.129 cm 3 cm −3 for 100% ET C and 65% ET C , respectively. The 16.5 kg ha −1 (NH 2 ) 2 CO (50% of the total N) that was applied during the growing season was completely hydrolyzed to NH 4 + within 7 days of application, while 4.36 mg cm −1 cumulative decay was achieved by the end of the 98-day growing season. We found that 86% of NH 4 + (74.25 mg cm −1 ) was nitrified to NO 3 − while 14% remained in the top 50 cm of the soil profile. The denitrification and free drainage of NO 3 − were similar for 100% ET C and 65% ET C , and the maximum nitrate was drained during the sprinkler irrigation period. By the end of the growing season, 30.8 mg cm −1 of nitrate was denitrified to N 2 and the reduction of nitrate plant uptake was 17.1% for the deficit irrigation section as compared to the fully irrigated side (19.44 mg cm −1 vs. 16.12 mg cm −1 ). This reduction in N uptake due to deficit irrigation on sunflower could help farmers conserve resources by reducing the amount of fertilizer required if deficit irrigation practices are implemented due to the limited availability of irrigation water. IntroductionNitrogen (N) plays a vital role in pl...

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“…Similar K s values measured on bedrock samples were reported by Katsura, Kosugi, Yamamoto, and Mizuyama (). Although the low permeability layer was thin and its water storage had little effect on the overall soil storage, its hydraulic conductivity defined the leaching potential of the entire soil profile (Baram et al, ). The calibrated K s of the purple soil was smaller than those reported by others (Long, Liu, & Liu, ) for both cultivated and uncultivated purple sloping soils.…”

Section: Discussionmentioning

confidence: 99%

Nitrate subsurface transport and losses in response to its initial distributions in sloped soils: An experimental and modelling study

Xie

Šimůnek

Zhang

et al. 2019

Hydrological Processes

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Transport and losses of nitrate from sloped soils are closely linked to nitrogen fertilizer management. Previous studies have always focused on different types of fertilizer applications and rarely analysed various initial nitrate distributions as a result of nitrogen fertilizer applications. Under certain conditions, both subsurface lateral saturated flow and vertical leaching dominate nitrate losses. Soil tank experiments and HYDRUS-2D modelling were used to better understand the subsurface nitrate transport and losses through lateral saturated flow and vertical leaching under various initial nitrate distributions. Low (L: 180 mg L −1 ), normal (N: 350 mg L −1 ), and high (H: 500 mg L −1 ) nitrate concentrations were used in five different distributions (NNNN, NLLN, LHHL, LNLN, and HNHN) along the slope of the tank. The first two treatments (NNNN and NLLN) were analysed both experimentally and numerically. Experiments were conducted under 12 rainfall events at intervals of 3 days. The HYDRUS-2D model was calibrated and validated against the experimental data and demonstrated good model performance. The other three treatments (LHHL, LNLN, and HNHN) were investigated using the calibrated model. Nitrate concentrations in purple sloped soils declined exponentially with time under intermittent rainfalls, predominantly in the upper soil layers. Non-uniform initial nitrate distributions contributed to larger differences between four locations along the slope in deeper soil layers. The nonuniform nitrate distribution either enhanced or reduced decreases in nitrate concentrations in areas with higher or lower initial nitrate concentrations, respectively.Higher nitrate concentrations at the slope foot and along the slope were reduced mainly by lateral flow and vertical leaching, respectively. Increasing nitrogen application rates increased subsurface nitrate losses. Mean subsurface lateral nitrate fluxes were twice as large as mean vertical leaching nitrate fluxes. However, due to longer leaching durations, total nitrate losses due to vertical leaching were comparable with those due to lateral flow, which indicated comparable environmental risks to surface waters and groundwater.

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Estimating Nitrate Leaching to Groundwater from Orchards: Comparing Crop Nitrogen Excess, Deep Vadose Zone Data‐Driven Estimates, and HYDRUS Modeling

Cited by 66 publications

References 50 publications

Carbon and Nitrogen Dynamics Affected by Drip Irrigation Methods and Fertilization Practices in a Pomegranate Orchard

Carbon and Nitrogen Dynamics Affected by Drip Irrigation Methods and Fertilization Practices in a Pomegranate Orchard

Effect of Deficit Irrigation on Nitrogen Uptake of Sunflower in the Low Desert Region of California

Nitrate subsurface transport and losses in response to its initial distributions in sloped soils: An experimental and modelling study

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