Modeling the irrigation requirements for an experimental site in Northern Alberta, Canada

10.7287/peerj.preprints.696v2 ◽

2014 ◽

Author(s):

Michel Rahbeh ◽

David Chanasyk ◽

Shane Patterson

Keyword(s):

Water Table ◽

Root Zone ◽

Winter Season ◽

Growing Season ◽

Annual Rainfall ◽

Quality Model ◽

Experimental Site ◽

Supplementary Irrigation ◽

Northern Alberta ◽

Irrigation Requirements

A combined methodology of the Root Zone Water Quality Model (RZWQM), the generation of stochastic rainfall realizations, and an historical meteorological record were used to determine the supplementary irrigation requirement for an experimental site located in northern Alberta. The site receives an annual rainfall of approximately 500 mm yr -1, and contains a fluctuating water table. The simulated results showed maximum irrigation requirements of 270 mm, however, half that amount can be required during an average or wet growing season of mean rainfall of 350 and 500 mm, respectively. The irrigation requirements were influenced by rainfall amount and distribution, downward flux and the subsequent fluctuation of the water table and the depth of water table at the beginning of the growing season, which was influenced by the winter season precipitation. The simulated results suggested that a water table less than 2 m deep from the ground surface can significantly reduce the irrigation requirements. Therefore, the winter precipitation and initial depth of the water table are suitable indicators of the likely requirement of irrigation during the growing season.

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Modeling the irrigation requirements for an experimental site in Northern Alberta, Canada

10.7287/peerj.preprints.696v1 ◽

2014 ◽

Author(s):

Michel Rahbeh ◽

David Chanasyk ◽

Shane Patterson

Keyword(s):

Water Table ◽

Root Zone ◽

Winter Season ◽

Growing Season ◽

Annual Rainfall ◽

Quality Model ◽

Experimental Site ◽

Supplementary Irrigation ◽

Northern Alberta ◽

Irrigation Requirements

A combined methodology of the Root Zone Water Quality Model (RZWQM), the generation of stochastic rainfall realizations, and an historical meteorological record were used to determine the supplementary irrigation requirement for an experimental site located in northern Alberta. The site receives an annual rainfall of approximately 500 mm yr -1, and contains a fluctuating water table. The simulated results showed maximum irrigation requirements of 270 mm, however, half that amount can be required during an average or wet growing season of mean rainfall of 350 and 500 mm, respectively. The irrigation requirements were influenced by rainfall amount and distribution, downward flux and the subsequent fluctuation of the water table and the depth of water table at the beginning of the growing season, which was influenced by the winter season precipitation. The simulated results suggested that a water table less than 2 m deep from the ground surface can significantly reduce the irrigation requirements. Therefore, the winter precipitation and initial depth of the water table are suitable indicators of the likely requirement of irrigation during the growing season.

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Contrasting responses of growing season ecosystem CO2exchange to variation in temperature and water table depth in two peatlands in northern Alberta, Canada

Journal of Geophysical Research Atmospheres ◽

10.1029/2010jg001512 ◽

2011 ◽

Vol 116 (G1) ◽

Cited By ~ 49

Author(s):

Angela C. Adkinson ◽

Kamran H. Syed ◽

Lawrence B. Flanagan

Keyword(s):

Water Table ◽

Growing Season ◽

Water Table Depth ◽

Northern Alberta

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Estimating nitrate loading from an intensively managed agricultural field to a shallow unconfined aquifer

Water Quality Research Journal ◽

10.2166/wqrjc.2013.136 ◽

2013 ◽

Vol 49 (1) ◽

pp. 10-22 ◽

Cited By ~ 8

Author(s):

P. J. Kuipers ◽

M. C. Ryan ◽

B. J. Zebarth

Keyword(s):

Water Table ◽

Root Zone ◽

Potential Evapotranspiration ◽

Growing Season ◽

Nitrogen Budget ◽

Agricultural Field ◽

Climate Data ◽

Nitrogen Surplus ◽

Nitrogen Budgets ◽

Intensively Managed

Nitrate loading from an intensively managed commercial red raspberry field to groundwater in the Abbotsford-Sumas Aquifer, British Columbia was estimated over a 1 yr period and compared with the nitrogen surplus calculated using a simple nitrogen budget. Nitrate loading was estimated as the product of recharge (estimated from climate data as total precipitation minus potential evapotranspiration (PET)) and monthly nitrate concentration measured at the water table. Most nitrate loading occurred when nitrate, accumulated in the root zone over the growing season, was leached following heavy autumn rainfall events. Elevated groundwater nitrate concentrations at the water table during the growing season when recharge was assumed to be negligible suggested that the nitrate loading was underestimated. The estimate of annual nitrate loading to the water table was high (174 kg N ha−1) suggesting that the tools currently available to growers to manage N in raspberry production are not adequate to protect groundwater quality. The calculated nitrogen surplus from the nitrogen budget (180 kg N ha−1) was similar to the measured nitrate loading suggesting that simple nitrogen budgets may be relatively effective indices of the risk of nitrate loading to groundwater.

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Simulating Annual Irrigation Requirement for Citrus on Excessively Drained Soils

HortScience ◽

10.21273/hortsci.41.6.1487 ◽

2006 ◽

Vol 41 (6) ◽

pp. 1487-1492 ◽

Cited By ~ 3

Author(s):

T. Adair Wheaton ◽

Lawrence R. Parsons ◽

K.T. Morgan

Keyword(s):

Root Zone ◽

Irrigation Management ◽

Management Strategies ◽

Rooting Depth ◽

Annual Rainfall ◽

Central Florida ◽

Available Water ◽

Wide Range ◽

Irrigation Depth ◽

Irrigation Requirements

A water use simulation for citrus (Citrus sinensis) was used to estimate the effects of climate, soil-available water, rooting depth, allowable depletion of available water, and partial coverage irrigation on the annual irrigation requirements. The soil in the study was excessively drained Candler sand (hyperthermic, uncoated Typic Quartzipsamments) of the Central Florida Ridge. Variation of annual rainfall from 667 to 1827 mm had a relatively small impact on annual irrigation requirements. Soil-available water, depth of root zone, and allowable depletion of available water all affected irrigation management and the number of irrigations annually. Simulated annual irrigation requirements varied over a wide range depending on the allowable depletion of soil-available water, irrigation depth, and the fraction of the land area that is irrigated. Effective rain estimated by the TR21 method during months of high rainfall was higher than estimates by the water budget. Monthly irrigation requirements varied seasonally and peaked in normally dry spring months of April and May. The irrigation simulation is a useful tool for examining the range of management strategies that can be considered for citrus.

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Combined simulation and optimization framework for irrigation scheduling in agriculture fields

Irrigation Science ◽

10.1007/s00271-021-00746-y ◽

2021 ◽

Author(s):

Mireia Fontanet ◽

Daniel Fernàndez-Garcia ◽

Gema Rodrigo ◽

Francesc Ferrer ◽

Josep Maria Villar

Keyword(s):

Crop Yields ◽

Root Zone ◽

Growing Season ◽

Irrigation Scheduling ◽

Irrigated Agriculture ◽

Traditional Methods ◽

Simulation And Optimization ◽

Optimization Framework ◽

Net Margin ◽

Combined Simulation

AbstractIn the context of growing evidence of climate change and the fact that agriculture uses about 70% of all the water available for irrigation in semi-arid areas, there is an increasing probability of water scarcity scenarios. Water irrigation optimization is, therefore, one of the main goals of researchers and stakeholders involved in irrigated agriculture. Irrigation scheduling is often conducted based on simple water requirement calculations without accounting for the strong link between water movement in the root zone, soil–water–crop productivity and irrigation expenses. In this work, we present a combined simulation and optimization framework aimed at estimating irrigation parameters that maximize the crop net margin. The simulation component couples the movement of water in a variably saturated porous media driven by irrigation with crop water uptake and crop yields. The optimization component assures maximum gain with minimum cost of crop production during a growing season. An application of the method demonstrates that an optimal solution exists and substantially differs from traditional methods. In contrast to traditional methods, results show that the optimal irrigation scheduling solution prevents water logging and provides a more constant value of water content during the entire growing season within the root zone. As a result, in this case, the crop net margin cost exhibits a substantial increase with respect to the traditional method. The optimal irrigation scheduling solution is also shown to strongly depend on the particular soil hydraulic properties of the given field site.

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Applications of the herbicide sethoxydim increase wheat yield in the absence of weeds

Australian Journal of Experimental Agriculture ◽

10.1071/ea9960555 ◽

1996 ◽

Vol 36 (5) ◽

pp. 555

Author(s):

ID Black ◽

CB Dyson ◽

AR Fischle

Keyword(s):

Leaf Growth ◽

Wheat Yield ◽

South Australia ◽

Growing Season ◽

Degree Days ◽

Experimental Site ◽

Yield Increase ◽

Growing Seasons ◽

Positive Linear Correlation ◽

Area North

In 11 experiments over 6 seasons the herbicide sethoxydim was applied to Machete, Spear and Blade wheat cultivars in the absence or near absence of weeds (10 sites) or where the weeds were controlled by selective herbicides (1 site), in the cropping area north of Adelaide, South Australia. The rates applied included 9-47 g a.i./ha at the 2-3 leaf growth stage and 9-74 g a.i./ha at early tillering. Except for the very long growing season of 1992, there was a highly significant positive linear correlation between the number of degree days in the growing season at each experimental site and relative mean yield increase of these sethoxydim treatments. Yield increases ranged from nil in growing seasons of about 1000 degree days to 32% in a growing season of 1480 degree days, with a median of 8% over the experiments.

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Assessing the impact of exceptional inter-annual climatic variability on rates of net ecosystem carbon dioxide exchange at Clara bog.

10.5194/egusphere-egu21-13414 ◽

2021 ◽

Author(s):

Matthew Saunders ◽

Ruchita Ingle ◽

Shane Regan

Keyword(s):

Water Table ◽

Elevated Temperatures ◽

Ecosystem Respiration ◽

Anthropogenic Activities ◽

Climatic Variability ◽

Growing Season ◽

Carbon Dioxide Exchange ◽

Mean Annual Temperature ◽

Monitoring Networks ◽

The Impact

Peatland ecosystems are integral to the mitigation of climate change as they represent significant terrestrial carbon sinks. In Ireland, peatlands cover ~20% of the land area but hold up to 75% of the soil organic carbon stock however many of these ecosystems (~85% of the total area) have been degraded due to anthropogenic activities such as agriculture, forestry and extraction for horticulture or energy. Furthermore, the carbon stocks that remain in these systems are vulnerable to inter-annual variation in climate, such as changes in precipitation and temperature, which can alter the hydrological status of these systems leading to changes in key biogeochemical processes and carbon and greenhouse gas exchange.&#160; During 2018 exceptional drought and heatwave conditions were reported across Northwestern Europe, where reductions in precipitation coupled with elevated temperatures were observed. Exceptional inter-annual climatic variability was also observed at Clara bog, a near natural raised bog in the Irish midlands when data from 2018 and 2019 were compared. Precipitation in 2018 was ~300 mm lower than 2019 while the average mean annual temperature was 0.5&#176;C higher. The reduction in precipitation, particularly during the growing season in 2018, consistently lowered the water table where ~150 consecutive days where the water table was >5cm below the surface of the bog were observed at the central ecotope location. The differing hydrological conditions between years resulted in the study area, as determined by the flux footprint of the eddy covariance tower, acting as a net source of carbon of 53.5 g C m-2 in 2018 and a net sink of 125.2 g C m-2 in 2019. The differences in the carbon dynamics between years were primarily driven by enhanced ecosystem respiration (Reco) and lower rates of Gross Primary Productivity (GPP) in the drier year, where the maximum monthly ratio of GPP:Reco during the growing season was 0.96 g C m-2 month in 2018 and 1.14 g C m-2 month in 2019. This study highlights both the vulnerability and resilience of these ecosystems to exceptional inter-annual climatic variability and emphasises the need for long-term monitoring networks to enhance our understanding of the impacts of these events when they occur.

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Real-time monitoring of nitrate transport in the deep vadose zone under a crop field – implications for groundwater protection

Hydrology and Earth System Sciences ◽

10.5194/hess-20-3099-2016 ◽

2016 ◽

Vol 20 (8) ◽

pp. 3099-3108 ◽

Cited By ~ 17

Author(s):

Tuvia Turkeltaub ◽

Daniel Kurtzman ◽

Ofer Dahan

Keyword(s):

Real Time ◽

Water Table ◽

Vadose Zone ◽

Land Surface ◽

Agricultural Land ◽

Root Zone ◽

Isotopic Signature ◽

Nitrate Transport ◽

Mass Migration ◽

Crop Field

Abstract. Nitrate is considered the most common non-point pollutant in groundwater. It is often attributed to agricultural management, when excess application of nitrogen fertilizer leaches below the root zone and is eventually transported as nitrate through the unsaturated zone to the water table. A lag time of years to decades between processes occurring in the root zone and their final imprint on groundwater quality prevents proper decision-making on land use and groundwater-resource management. This study implemented the vadose-zone monitoring system (VMS) under a commercial crop field. Data obtained by the VMS for 6 years allowed, for the first time known to us, a unique detailed tracking of water percolation and nitrate migration from the surface through the entire vadose zone to the water table at 18.5 m depth. A nitrate concentration time series, which varied with time and depth, revealed – in real time – a major pulse of nitrate mass propagating down through the vadose zone from the root zone toward the water table. Analysis of stable nitrate isotopes indicated that manure is the prevalent source of nitrate in the deep vadose zone and that nitrogen transformation processes have little effect on nitrate isotopic signature. The total nitrogen mass calculations emphasized the nitrate mass migration towards the water table. Furthermore, the simulated pore-water velocity through analytical solution of the convection–dispersion equation shows that nitrate migration time from land surface to groundwater is relatively rapid, approximately 5.9 years. Ultimately, agricultural land uses, which are constrained to high nitrogen application rates and coarse soil texture, are prone to inducing substantial nitrate leaching.

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