scholarly journals Simulation of the soil water balance of wheat using daily weather forecast messages to estimate the reference evapotranspiration

2009 ◽  
Vol 13 (7) ◽  
pp. 1045-1059 ◽  
Author(s):  
J. B. Cai ◽  
Y. Liu ◽  
D. Xu ◽  
P. Paredes ◽  
L. S. Pereira
Keyword(s):  
Wind Speed ◽  
Water Balance ◽  
Soil Water ◽  
Real Time ◽  
Minimum Temperature ◽  
Reference Evapotranspiration ◽  
Weather Forecast ◽  
Irrigation Scheduling ◽  
Daily Weather ◽  
Model Predictions

Abstract. Aiming at developing real time water balance modelling for irrigation scheduling, this study assesses the accuracy of using the reference evapotranspiration (ETo) estimated from daily weather forecast messages (ETo,WF) as model input. A previous study applied to eight locations in China (Cai et al., 2007) has shown the feasibility for estimating ETo,WF with the FAO Penman-Monteith equation using daily forecasts of maximum and minimum temperature, cloudiness and wind speed. In this study, the global radiation is estimated from the difference between the forecasted maximum and minimum temperatures, the actual vapour pressure is estimated from the forecasted minimum temperature and the wind speed is obtained from converting the common wind scales into wind speed. The present application refers to a location in the North China Plain, Daxing, for the wheat crop seasons of 2005–2006 and 2006–2007. Results comparing ETo,WF with ETo computed with observed data (ETo,obs) have shown favourable goodness of fitting indicators and a RMSE of 0.77 mm d−1. ETo was underestimated in the first year and overestimated in the second. The water balance model ISAREG was calibrated with data from four treatments for the first season and validated with data of five treatments in the second season using observed weather data. The calibrated crop parameters were used in the simulations of the same treatments using ETo,WF as model input. Errors in predicting the soil water content are small, 0.010 and 0.012 m3 m−3, respectively for the first and second year. Other indicators also confirm the goodness of model predictions. It could be concluded that using ETo computed from daily weather forecast messages provides for accurate model predictions and to use an irrigation scheduling model in real time.

scholarly journals Simulation of the soil water balance of wheat using daily weather forecast messages to estimate the reference evapotranspiration

2009 ◽  
Vol 6 (1) ◽  
pp. 697-728
Author(s):  
J. Cai ◽  
Y. Liu ◽  
D. Xu ◽  
P. Paredes ◽  
L. S. Pereira
Keyword(s):  
Wind Speed ◽  
Water Balance ◽  
Soil Water ◽  
Minimum Temperature ◽  
Reference Evapotranspiration ◽  
Weather Forecast ◽  
Irrigation Scheduling ◽  
Soil Water Balance ◽  
Daily Weather ◽  
Model Predictions

Abstract. Aiming at developing real time water balance modelling for irrigation scheduling, this study assesses the accuracy of using the reference evapotranspiration (ETo) estimated from daily weather forecast messages (ETo,WF) as model input. A previous study applied to eight locations in China (Cai et al., 2007) has shown the feasibility for estimating ETo,WF with the FAO Penmam-Monteith equation using daily forecasts of maximum and minimum temperature, cloudiness and wind speed. In this study, the global radiation is estimated from the difference between the forecasted maximum and minimum temperatures, the actual vapour pressure is estimated from the forecasted minimum temperature and the wind speed is obtained from converting the common wind scales into wind speed. The present application refers to a location in the North China Plain, Daxing, for the wheat crop seasons of 2005–2006 and 2006–2007. Results comparing ETo,WF with ETo computed with observed data (ETo, obs) have shown favourable goodness of fitting indicators and a RMSE of 0.77 mm d−1. ETo was underestimated in the first year and overestimated in the second. The water balance model ISAREG was calibrated and validated for both years using ETo, obs by comparing the predicted and observed soil water content relative to various irrigation treatments. The calibrated crop parameters were used in the simulations of the same treatments using ETo,WF as model input. Errors in predicting the soil water balance are small, 0.010 and 0.012 m3 m−3 respectively for the first and second year. Other indicators also confirm the goodness of model predictions. It could be concluded that using ETo computed from daily weather forecast messages provides for accurate model predictions, thus making it viable to use an irrigation scheduling model in real time with daily weather forecast messages.

scholarly journals ESTIMATIVA DA DEMANDA HÍDRICA DA SOJA UTILIZANDO MODELO DE BALANÇO HÍDRICO DO SOLO E DADOS DA PREVISÃO DO TEMPO

Irriga ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 492-507
Author(s):  
Zanandra Boff Oliveira ◽  
ALBERTO EDUARDO KNIES ◽  
EDUARDO LEONEL BOTTEGA ◽  
Clarissa Moraes da Silva
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Water Demand ◽  
Reference Evapotranspiration ◽  
Weather Forecast ◽  
Water Balance Model ◽  
Soil Water Balance ◽  
Balance Model ◽  
Forecast Data ◽  
Santa Maria

ESTIMATIVA DA DEMANDA HÍDRICA DA SOJA UTILIZANDO MODELO DE BALANÇO HÍDRICO DO SOLO E DADOS DA PREVISÃO DO TEMPO     ZANANDRA BOFF DE OLIVEIRA1; ALBERTO EDUARDO KNIES2; EDUARDO LEONEL BOTTEGA1 E CLARISSA MORAES DA SILVA3   1 Universidade Federal de Santa Maria Campus Cachoeira do Sul, Curso de Engenharia Agrícola, Rodovia Taufik Germano, 3013, Passo D'Areia, CEP. 96503-205, Cachoeira do Sul/RS, Brasil, [email protected]; [email protected]. 2 Universidade Estadual do Rio grande do Sul, Unidade de Cachoeira o Sul, Rua Sete de Setembro, 1040, Centro, CEP. 96508-010, Cachoeira do Sul/RS, Brasil, [email protected]. 3 Programa de Pós-Graduação em Engenharia Agrícola (PPGEA), Centro de Ciências Rurais, 3° andar, sala 3325, Campus Universitário, CEP.9105-900, Santa Maria/RS, Brasil, [email protected]     1 RESUMO   A estimativa da demanda hídrica dos cultivos em tempo real e futuro pode contribuir para a maior eficiência do uso da água na agricultura irrigada. O presente estudo teve como objetivo estimar o requerimento hídrico da soja, utilizando o modelo de balanço hídrico CROPWAT com dados da previsão do tempo para o cálculo da evapotranspiração de referência (ETo). Para isso, o estudo foi conduzido em duas etapas: coleta de dados de solo, da previsão meteorológica e da cultura em três anos agrícolas: 2017/18, 2018/19 e 2019; modelagem das condições observadas a campo pelo modelo CROPWAT. A modelagem foi eficiente (d=0,99) para a estimativa da capacidade de água disponível no solo, apresentando baixo erro (RMSE = 2,18 mm) em comparação  aos valores medidos a campo, resultando na recomendação da lâmina de irrigação igual à aplicada na cultura, sendo esta de 132, 135 e 60 mm, respectivamente, para os anos agrícolas 2017/18, 2018/19 e 2019. A utilização do modelo de balanço hídrico do solo CROPWAT com dados da previsão do tempo para o cálculo da evapotranspiração de referência pode ser utilizada como ferramenta para a estimativa do requerimento hídrico da soja na região edafoclimática de Cachoeira do Sul-RS.   Keywords: simulação do balanço hídrico, manejo da irrigação, previsão meteorológica.     OLIVEIRA, Z.B.; KNIES, A.E.; BOTTEGA, E.L. SILVA, C.M. ESTIMATE OF SOY WATER DEMAND USING SOIL WATER BALANCE MODEL AND WEATHER FORECAST DATA     2 ABSTRACT   Estimating the water demand for crops in real and future time can contribute to greater efficiency in the use of water in irrigated agriculture. The present study aimed to estimate the water requirement of soy using the water balance model CROPWAT with data from the weather forecast for the calculation of reference evapotranspiration (ETo). For this, the study was conducted in two stages: collection of soil data, meteorological forecast and culture in three agricultural years: 2017/18, 2018/19 and 2019; modeling of the conditions observed in the field by the CROPWAT model. The modeling was efficient (d = 0.99) to estimate the available water capacity in the soil, presenting  low error (RMSE = 2.18 mm) compared to the values measured in the field, resulting in the recommendation of  irrigation depth equal to that applied to the crop, which is 132, 135 and 60 mm, respectively, for the agricultural years 2017/18, 2018/19 and 2019. The use of the CROPWAT soil water balance model with weather forecast data for the calculation of the Reference evapotranspiration can be used as a tool to estimate the water requirement of soybean in the edaphoclimatic region of Cachoeira do Sul-RS.   Keywords: simulação do balanço hídrico, manejo da irrigação, previsão meteorológica.

IrrigaSys – a decision support system for irrigation management in the Sorraia Valley region, Portugal

2020 ◽  
Author(s):  
Lucian Simionesei ◽  
Tiago B. Ramos ◽  
Jorge Palma ◽  
Ana R. Oliveira ◽  
Ramiro Neves
Keyword(s):  
Decision Support ◽  
Water Balance ◽  
Decision Support System ◽  
Soil Water ◽  
Support System ◽  
Weather Forecast ◽  
Irrigation Scheduling ◽  
Mobile App ◽  
Soil Water Balance ◽  
Sentinel 2

<p>IrrigaSys is a decision support system (DSS) for irrigation water management based on online, open<br>access tools. The system includes remote access to local meteorological stations for weather<br>conditions, a MM5 model for weather forecast, the MOHID-Land model for the computation of the<br>soil water balance and irrigation scheduling, and a MySQL database for data repository. Despite its<br>complexity, the data necessary to run IrrigaSys is minimal, and include the location of the agricultural<br>field, crop type, sowing and harvest dates, soil texture, irrigation method, and daily/weekly irrigation<br>depths applied by the farmer. Based on this information, the system automatically downloads the<br>weather data from the meteorological station located closest to the agricultural plot, as well as the<br>weather forecast for the seven days following the current date. The soil water balance is then<br>computed for the previous and following week as well as the crop irrigation needs using the MOHIDLand<br>model. Results are made available via a web interface, a mobile app, SMS, and email. Besides the<br>model outputs, the IrrigaSys further provides the Normalized Difference Vegetation Index (NDVI) for<br>the agricultural field. The NDVI is computed from Sentinel 2 spectral bands with a resolution of 10m,<br>and is updated every time new Sentinel 2 imagery data (with cloud cover < 10%) is available. The<br>IrrigaSys has been developed in close cooperation with the Water Board Association of the Sorraia<br>Valley irrigation district (15360 ha), southern Portugal, over the last 5 years, supporting 103 plots of<br>30 farmers during the last irrigation season. As a result, the main limitation is naturally associated to<br>the difficulty in providing reliable estimates for all field plots based on calibrated model data. As the<br>next step, the service should start automatically identifying the culture status based on satellite<br>information as well as providing fertigation recommendations to farmers.</p>

scholarly journals Evaluation of a Hybrid Reflectance-Based Crop Coefficient and Energy Balance Evapotranspiration Model for Irrigation Management

2018 ◽  
Vol 61 (2) ◽  
pp. 533-548 ◽  
Author(s):  
J. Burdette Barker ◽  
Christopher M. U. Neale ◽  
Derek M. Heeren ◽  
Andrew E. Suyker
Keyword(s):  
Remote Sensing ◽  
Energy Balance ◽  
Water Balance ◽  
Real Time ◽  
Eddy Covariance ◽  
Irrigation Management ◽  
Crop Coefficient ◽  
Irrigation Scheduling ◽  
Balance Model ◽  
Crop Coefficients

Abstract. Accurate generation of spatial soil water maps is useful for many types of irrigation management. A hybrid remote sensing evapotranspiration (ET) model combining reflectance-based basal crop coefficients (Kcbrf) and a two-source energy balance (TSEB) model was modified and validated for use in real-time irrigation management. We modeled spatial ET for maize and soybean fields in eastern Nebraska for the 2011-2013 growing seasons. We used Landsat 5, 7, and 8 imagery as remote sensing inputs. In the TSEB, we used the Priestly-Taylor (PT) approximation for canopy latent heat flux, as in the original model formulations. We also used the Penman-Monteith (PM) approximation for comparison. We compared energy balance fluxes and computed ET with measurements from three eddy covariance systems within the study area. Net radiation was underestimated by the model when data from a local weather station were used as input, with mean bias error (MBE) of -33.8 to -40.9 W m-2. The measured incident solar radiation appeared to be biased low. The net radiation model performed more satisfactorily when data from the eddy covariance flux towers were input into the model, with MBE of 5.3 to 11.2 W m-2. We removed bias in the daily energy balance ET using a dimensionless multiplier that ranged from 0.89 to 0.99. The bias-corrected TSEB ET, using weather data from a local weather station and with local ground data in thermal infrared imagery corrections, had MBE = 0.09 mm d-1 (RMSE = 1.49 mm d-1) for PM and MBE = 0.04 mm d-1 (RMSE = 1.18 mm d-1) for PT. The hybrid model used statistical interpolation to combine the two ET estimates. We computed weighting factors for statistical interpolation to be 0.37 to 0.50 for the PM method and 0.56 to 0.64 for the PT method. Provisions were added to the model, including a real-time crop coefficient methodology, which allowed seasonal crop coefficients to be computed with relatively few remote sensing images. This methodology performed well when compared to basal crop coefficients computed using a full season of input imagery. Water balance ET compared favorably with the eddy covariance data after incorporating the TSEB ET. For a validation dataset, the magnitude of MBE decreased from -0.86 mm d-1 (RMSE = 1.37 mm d-1) for the Kcbrf alone to -0.45 mm d-1 (RMSE = 0.98 mm d-1) and -0.39 mm d-1 (RMSE = 0.95 mm d-1) with incorporation of the TSEB ET using the PM and PT methods, respectively. However, the magnitudes of MBE and RMSE were increased for a running average of daily computations in the full May-October periods. The hybrid model did not necessarily result in improved model performance. However, the water balance model is adaptable for real-time irrigation scheduling and may be combined with forecasted reference ET, although the low temporal frequency of satellite imagery is expected to be a challenge in real-time irrigation management. Keywords: Center-pivot irrigation, ET estimation methods, Evapotranspiration, Irrigation scheduling, Irrigation water balance, Model validation, Variable-rate irrigation.

Soil Water Measurement as Basis to Optimize Irrigation Scheduling: A Review

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 553f-554
Author(s):  
A.K. Alva ◽  
A. Fares
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Soil Water ◽  
Real Time ◽  
Soil Water Content ◽  
Root Zone ◽  
Soil Water Potential ◽  
Irrigation Scheduling ◽  
Rooting Depth ◽  
The Impact

Supplemental irrigation is often necessary for high economic returns for most cropping conditions even in humid areas. As irrigation costs continue to increase more efforts should be exerted to minimize these costs. Real time estimation and/or measurement of available soil water content in the crop root zone is one of the several methods used to help growers in making the right decision regarding timing and quantity of irrigation. The gravimetric method of soil water content determination is laborious and doesn't suite for frequent sampling from the same location because it requires destructive soil sampling. Tensiometers, which measure soil water potential that can be converted into soil water content using soil moisture release curves, have been used for irrigation scheduling. However, in extreme sandy soils the working interval of tensiometer is reduced, hence it may be difficult to detect small changes in soil moisture content. Capacitance probes which operate on the principle of apparent dielectric constant of the soil-water-air mixture are extremely sensitive to small changes in the soil water content at short time intervals. These probes can be placed at various depths within and below the effective rooting depth for a real time monitoring of the water content. Based on this continuous monitoring of the soil water content, irrigation is scheduled to replenish the water deficit within the rooting depth while leaching below the root zone is minimized. These are important management practices aimed to increase irrigation efficiency, and nutrient uptake efficiency for optimal crop production, while minimizing the impact of agricultural non-point source pollutants on the groundwater quality.

Young lime tree evapotranspiration measurements in lysimeters with automated irrigation

2021 ◽  
Author(s):  
Ana belén Mira-García ◽  
Juan Vera ◽  
Wenceslao Conejero ◽  
Mª Carmen Ruiz-Sánchez
Keyword(s):  
Gas Exchange ◽  
Water Balance ◽  
Water Content ◽  
Soil Water ◽  
Real Time ◽  
Soil Water Content ◽  
Water Status ◽  
Soil Water Balance ◽  
Crop Evapotranspiration ◽  
Lime Tree

<p>Lime tree growing area is increasing in Mediterranean temperate regions. In these areas, climate change scenario is expected to raise air temperature and water shortages. Such scenario requires new approaches to implement a precision irrigation in agriculture. In order to use water more efficiently, it becomes necessary to accurately determining the crop water needs, which are estimated by crop evapotranspiration computations (ETc). In this study the ETc of young lime trees grown under Mediterranean conditions were determined using the soil water balance method. For this purpose, two-year old lime trees (Citrus latifolia Tan., cv. Bearss) grafted on C. macrophylla rootstock were cultivated in pot-lysimeters, equipped with capacitance and granular matric sensors for real-time monitoring of the soil water status. Irrigation, drainage, and pot weight were also monitored continuously. All measurements were integrated into a telemetry platform. Agro-meteorological variables, plant water status (stem (Ψ<sub>stem</sub>) and leaf (Ψ<sub>leaf</sub>) water potentials), and leaf gas exchange parameters (stomatal conductance (g<sub>s</sub>) and net photosynthesis (P<sub>n</sub>)) were measured. Along the experiment, an automated irrigation protocol based on volumetric soil water content (θ<sub>v</sub>) threshold values were programmed, guaranteeing an adequate lime tree water status. Irrigation dose was calculated based on a feed-back strategy maintaining θ<sub>v </sub>within 30% management allowed depletion.</p><p>During the experimental period, the lime trees were well irrigated as revealed midday Ψ<sub>stem </sub>values that were maintained above -0.8 MPa. Also, the mean seasonal values of ≈ 7 µmol m<sup>−2</sup> s<sup>−1</sup> and 80 mmol m<sup>−2</sup> s<sup>−1</sup>, for P<sub>n</sub> and g<sub>s</sub>, respectively, indicated optimal gas exchange values. The computed water balance parameters yielded values for the crop evapotranspiration from 0.25<sup></sup>to 2.56 mm day<sup>-1</sup>, in winter and summer months, respectively, with maximum values in July when evaporative demand conditions were the highest. This soil water balance was daily validated by the pot weight balance through the year.</p><p>In conclusion, the automated irrigation of young potted lime trees, using soil water content as a control system variable, has ensured an adequate lime tree water status. A simple, robust weighing/drainage lysimeter, with real-time monitoring of the soil water balance parameters, has been proved practical and economical tool for crop evapotranspiration measurements.</p><p>Acknowledgments: This work was funded by Spanish Agencia Estatal de Investigación (PID2019-106226RB-C2-1/AEI/10.13039/501100011033) and Fundación Séneca, Región de Murcia (19903/GERM/15) projects.</p>

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