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This study aims to evaluate NASA POWER reanalysis products for daily surface maximum (Tmax) and minimum (Tmin) temperatures, solar radiation (Rs), relative humidity (RH) and wind speed (Ws) when compared with observed data from 14 distributed weather stations across Alentejo Region, Southern Portugal, with a hot summer Mediterranean climate. Results showed that there is good agreement between NASA POWER reanalysis and observed data for all parameters, except for wind speed, with coefficient of determination (R2) higher than 0.82, with normalized root mean square error (NRMSE) varying, from 8 to 20%, and a normalized mean bias error (NMBE) ranging from –9 to 26%, for those variables. Based on these results, and in order to improve the accuracy of the NASA POWER dataset, two bias corrections were performed to all weather variables: one for the Alentejo Region as a whole; another, for each location individually. Results improved significantly, especially when a local bias correction is performed, with Tmax and Tmin presenting an improvement of the mean NRMSE of 6.6 °C (from 8.0 °C) and 16.1 °C (from 20.5 °C), respectively, while a mean NMBE decreased from 10.65 to 0.2%. Rs results also show a very high goodness of fit with a mean NRMSE of 11.2% and mean NMBE equal to 0.1%. Additionally, bias corrected RH data performed acceptably with an NRMSE lower than 12.1% and an NMBE below 2.1%. However, even when a bias correction is performed, Ws lacks the performance showed by the remaining weather variables, with an NRMSE never lower than 19.6%. Results show that NASA POWER can be useful for the generation of weather data sets where ground weather stations data is of missing or unavailable.
Gonçalo Rodrigues; Ricardo Braga. Evaluation of NASA POWER Reanalysis Products to Estimate Daily Weather Variables in a Hot Summer Mediterranean Climate. Agronomy 2021, 11, 1207 .
AMA StyleGonçalo Rodrigues, Ricardo Braga. Evaluation of NASA POWER Reanalysis Products to Estimate Daily Weather Variables in a Hot Summer Mediterranean Climate. Agronomy. 2021; 11 (6):1207.
Chicago/Turabian StyleGonçalo Rodrigues; Ricardo Braga. 2021. "Evaluation of NASA POWER Reanalysis Products to Estimate Daily Weather Variables in a Hot Summer Mediterranean Climate." Agronomy 11, no. 6: 1207.
The FAO-56 Penman–Monteith (PM) equation is regarded as the most accurate equation to estimate reference evapotranspiration (ETo). However, it requires a broad range of data that may not be available or of reasonable quality. In this study, nine temperature-based methods were assessed for ETo estimation during the irrigation at fourteen locations distributed through a hot-summer Mediterranean climate region of Alentejo, Southern Portugal. Additionally, for each location, the Hargreaves–Samani radiation adjustment coefficient (kRs) was calibrated and validated to evaluate the appropriateness of using the standard value, creating a locally adjusted Hargreaves–Samani (HS) equation. The accuracy of each method was evaluated by statistically comparing their results with those obtained by PM. Results show that the calibration of the kRs, a locally adjusted HS method can be used to estimate daily ETo acceptably well, with RMSE lower than 0.88 mm day−1, an estimation error lower than 4% and a R2 higher than 0.69, proving to be the most accurate model for 8 (out of 14) locations. A modified Hargreaves–Samani method also performed acceptably for 4 locations, with a RMSE of 0.72–0.84 mm day−1, a slope varying from 0.95 to 1.01 and a R2 higher than 0.78. One can conclude that, when weather data is missing, a calibrated HS equation is adequate to estimate ETo during the irrigation season.
Gonçalo Rodrigues; Ricardo Braga. Estimation of Reference Evapotranspiration during the Irrigation Season Using Nine Temperature-Based Methods in a Hot-Summer Mediterranean Climate. Agriculture 2021, 11, 124 .
AMA StyleGonçalo Rodrigues, Ricardo Braga. Estimation of Reference Evapotranspiration during the Irrigation Season Using Nine Temperature-Based Methods in a Hot-Summer Mediterranean Climate. Agriculture. 2021; 11 (2):124.
Chicago/Turabian StyleGonçalo Rodrigues; Ricardo Braga. 2021. "Estimation of Reference Evapotranspiration during the Irrigation Season Using Nine Temperature-Based Methods in a Hot-Summer Mediterranean Climate." Agriculture 11, no. 2: 124.
This paper aims to determine farmers’ willingness to pay for irrigation water, using the residual value method, for the most representative crops at six Irrigation Communities from the Alentejo region, southern Portugal. The main objective of this assessment was to determine the value that farmers would be able to pay for the water to irrigate different crops at different locations, and to show that this approach can be used to provide information about farming economic sustainability and provide support on if crop prices need to be revised or if a national policy should be conceived to cover for farming costs. The results show that vegetables and fruit trees have the highest Residual Value of Water (RVW), while Wheat, Sunflower, Fodder crops, Semi-intensive Olive Orchards and Rice tend to have an RVW lower than the current variable irrigation water price. The results also show that, while, for Melon, Tomato, Onion, Super-high-density Olive Orchards, Peach and Almonds, both yields and price may decrease significantly, allowing one to save for faming inputs, Sunflower and Rice would require an increase in yields or prices to cover for the irrigation water price.
Gonçalo C. Rodrigues; Francisco G. Da Silva; José C. Coelho. Determining Farmers’ Willingness to Pay for Irrigation Water in the Alentejo Region (Southern Portugal) by the Residual Value Method. Agronomy 2021, 11, 142 .
AMA StyleGonçalo C. Rodrigues, Francisco G. Da Silva, José C. Coelho. Determining Farmers’ Willingness to Pay for Irrigation Water in the Alentejo Region (Southern Portugal) by the Residual Value Method. Agronomy. 2021; 11 (1):142.
Chicago/Turabian StyleGonçalo C. Rodrigues; Francisco G. Da Silva; José C. Coelho. 2021. "Determining Farmers’ Willingness to Pay for Irrigation Water in the Alentejo Region (Southern Portugal) by the Residual Value Method." Agronomy 11, no. 1: 142.
The Food and Agricultural Organization of the United Nations (FAO) Penman–Monteith (PM) method is widely regarded as the most effective reference evapotranspiration (ETo) estimator; however, it requires a wide range of data that may be scarce in some rural regions. When feasible relative humidity, solar radiation and wind speed data are unavailable, a temperature-based method may be useful to estimate ETo and provide suitable data to support irrigation management. This study has evaluated the accuracy of two ETo estimations methods: (1) a locally and monthly adjusted Hargreaves–Samani (HS) equation; (2) a simple procedure that only uses maximum temperature and a temperature adjustment coefficient (MaxTET). Results show that, if a monthly adjusted radiation adjustment coefficient (kRs) is calibrated for each site, acceptable ETo estimations (RMSE and R2 equal to 0.79 for the entire region) can be achieved. Results also show that a procedure to estimate ETo based only on maximum temperature performs acceptably, when compared with ETo estimation using PM equation (RMSE = 0.83 mm day−1 and R2 = 0.77 for Alentejo). When comparing these results with the ones attained when adopting a monthly adjusted HS method, the MaxTET procedure proves to be an accurate ETo estimator. Results also show that both methods can be used to estimate ETo when weather data are scarce.
Gonçalo Rodrigues; Ricardo Braga. A Simple Procedure to Estimate Reference Evapotranspiration during the Irrigation Season in a Hot-Summer Mediterranean Climate. Sustainability 2021, 13, 349 .
AMA StyleGonçalo Rodrigues, Ricardo Braga. A Simple Procedure to Estimate Reference Evapotranspiration during the Irrigation Season in a Hot-Summer Mediterranean Climate. Sustainability. 2021; 13 (1):349.
Chicago/Turabian StyleGonçalo Rodrigues; Ricardo Braga. 2021. "A Simple Procedure to Estimate Reference Evapotranspiration during the Irrigation Season in a Hot-Summer Mediterranean Climate." Sustainability 13, no. 1: 349.
In the Mediterranean region, climate change is likely to generate an increase in water demand and the deterioration of its quality. The adoption of precision viticulture and the best available techniques aiming at sustainable production, minimizing the impact on natural resources and reducing production costs, has therefore been a goal of winegrowers. In this work, the water footprint (WFP) in the wine sector was evaluated, from the vineyard to the bottle, through the implementation of a methodology based on field experiments and life cycle assessment (LCA) on two Portuguese case studies. Regarding direct water footprint, it ranged from 366 to 899 L/FU (0.75 L bottle), with green water being the most significant component, representing more than 50% of the overall water footprint. The approach used in the current study revealed that although more than 97.5% of the water footprint is associated with vineyard, the winery stage is responsible for more than 75% of the global warming potential indicator. A linear correlation between the carbon footprint and the indirect blue water footprint was also observed for both case studies. Climate change is expected to cause an earlier and prolonged water stress period, resulting in an increase of about 40% to 82% of blue WFP.
Artur Saraiva; Pedro Presumido; José Silvestre; Manuel Feliciano; Gonçalo Rodrigues; Pedro E Silva; Miguel Damásio; António Ribeiro; Sofia Ramôa; Luís Ferreira; Artur Gonçalves; Albertina Ferreira; Anabela Grifo; Ana Paulo; António Ribeiro; Adelaide Oliveira; Igor Dias; Helena Mira; Anabela Amaral; Henrique Mamede; Margarida Oliveira. Water Footprint Sustainability as a Tool to Address Climate Change in the Wine Sector: A Methodological Approach Applied to a Portuguese Case Study. Atmosphere 2020, 11, 934 .
AMA StyleArtur Saraiva, Pedro Presumido, José Silvestre, Manuel Feliciano, Gonçalo Rodrigues, Pedro E Silva, Miguel Damásio, António Ribeiro, Sofia Ramôa, Luís Ferreira, Artur Gonçalves, Albertina Ferreira, Anabela Grifo, Ana Paulo, António Ribeiro, Adelaide Oliveira, Igor Dias, Helena Mira, Anabela Amaral, Henrique Mamede, Margarida Oliveira. Water Footprint Sustainability as a Tool to Address Climate Change in the Wine Sector: A Methodological Approach Applied to a Portuguese Case Study. Atmosphere. 2020; 11 (9):934.
Chicago/Turabian StyleArtur Saraiva; Pedro Presumido; José Silvestre; Manuel Feliciano; Gonçalo Rodrigues; Pedro E Silva; Miguel Damásio; António Ribeiro; Sofia Ramôa; Luís Ferreira; Artur Gonçalves; Albertina Ferreira; Anabela Grifo; Ana Paulo; António Ribeiro; Adelaide Oliveira; Igor Dias; Helena Mira; Anabela Amaral; Henrique Mamede; Margarida Oliveira. 2020. "Water Footprint Sustainability as a Tool to Address Climate Change in the Wine Sector: A Methodological Approach Applied to a Portuguese Case Study." Atmosphere 11, no. 9: 934.
In the Mediterranean region, water scarcity has already prompted concern in the wine sector due to the strong impact it has on vineyard productivity and wine quality. Water footprint is an indicator that takes account of all the water involved in the creation of a product and may help producers to identify hotspots, and reduce water consumption and the corresponding production costs. In recent years several studies have been reported on wine water footprint determination, but mostly focused on the viticulture phase or assuming no grey water footprint at the winery since it has a treatment system. In the framework of the WineWaterFootprint project a medium-size winery was monitored, with direct measurements, regarding determination of the blue and grey components of water footprint. The determined winery water footprint ranged from 9.6 to 12.7 L of water per wine bottle of 0.75 L, the wastewater produced being responsible for about 98%, which means that the grey component cannot be disregarded. The developed scenarios show that a potential reduction of 87% in winery water footprint can be obtained with almost no investment. The challenge of reducing the grey footprint is not in technology development, but rather in the proper maintenance and monitoring of treatment systems.
Artur Saraiva; Gonçalo Rodrigues; H. Mamede; J. Silvestre; Igor Dias; M. Feliciano; P. Oliveira E Silva; Margarida Oliveira. The impact of the winery's wastewater treatment system on the winery water footprint. Water Science and Technology 2019, 80, 1823 -1831.
AMA StyleArtur Saraiva, Gonçalo Rodrigues, H. Mamede, J. Silvestre, Igor Dias, M. Feliciano, P. Oliveira E Silva, Margarida Oliveira. The impact of the winery's wastewater treatment system on the winery water footprint. Water Science and Technology. 2019; 80 (10):1823-1831.
Chicago/Turabian StyleArtur Saraiva; Gonçalo Rodrigues; H. Mamede; J. Silvestre; Igor Dias; M. Feliciano; P. Oliveira E Silva; Margarida Oliveira. 2019. "The impact of the winery's wastewater treatment system on the winery water footprint." Water Science and Technology 80, no. 10: 1823-1831.
Umbrella pine (Pinus pinea L.) cones take three years to develop. With the increasing frequency of extreme droughts, water available for trees has decreased—climate change is a reality. The cone’s survival in its first two years of development and the average cone weight during its last year of maturation is affected, thus, reducing kernel quantity and quality. Climate change has resulted in forest fires becoming an inescapable issue in forest management planning. A literature review was carried out, focusing, on one hand, the predicted climatic changes for the Mediterranean basin and, on the other hand, the umbrella pine silvicultural mechanisms at tree, stand, and landscape levels that may help to face these constraints. Finally, the Portuguese case was focused, describing the management practices that are being adopted to achieve, even when the period of cone formation and growth include dry years, one to six tons of cones per hectare per year in adult stands.
João A. Freire; Gonçalo Rodrigues; Margarida Tomé. Climate Change Impacts on Pinus pinea L. Silvicultural System for Cone Production and Ways to Contour Those Impacts: A Review Complemented with Data from Permanent Plots. Forests 2019, 10, 169 .
AMA StyleJoão A. Freire, Gonçalo Rodrigues, Margarida Tomé. Climate Change Impacts on Pinus pinea L. Silvicultural System for Cone Production and Ways to Contour Those Impacts: A Review Complemented with Data from Permanent Plots. Forests. 2019; 10 (2):169.
Chicago/Turabian StyleJoão A. Freire; Gonçalo Rodrigues; Margarida Tomé. 2019. "Climate Change Impacts on Pinus pinea L. Silvicultural System for Cone Production and Ways to Contour Those Impacts: A Review Complemented with Data from Permanent Plots." Forests 10, no. 2: 169.
Paula Paredes; Luis Santos Pereira; Gonçalo C. Rodrigues; Nuno Botelho; Maria Odete Torres. Using the FAO dual crop coefficient approach to model water use and productivity of processing pea (Pisum sativum L.) as influenced by irrigation strategies. Agricultural Water Management 2017, 189, 5 -18.
AMA StylePaula Paredes, Luis Santos Pereira, Gonçalo C. Rodrigues, Nuno Botelho, Maria Odete Torres. Using the FAO dual crop coefficient approach to model water use and productivity of processing pea (Pisum sativum L.) as influenced by irrigation strategies. Agricultural Water Management. 2017; 189 ():5-18.
Chicago/Turabian StylePaula Paredes; Luis Santos Pereira; Gonçalo C. Rodrigues; Nuno Botelho; Maria Odete Torres. 2017. "Using the FAO dual crop coefficient approach to model water use and productivity of processing pea (Pisum sativum L.) as influenced by irrigation strategies." Agricultural Water Management 189, no. : 5-18.
The previously field calibrated approach of coupling the SIMDualKc soil water balance model with the Stewart’s water-yield model was used to assess the impacts of alternative sowing dates and irrigation schedules upon malting barley (Hordeum vulgare L. cv. Publican) yields. To properly support modelling, the study was based upon field observations in a farmers’ field during 2012 and 2013 crop seasons, respectively a dry and a wet year. The study aimed at assessing alternative sowing dates and irrigation management in terms of water use, yields, water productivity and the economic water productivity ratio (EWPR) that relates the yield value with the production costs referring to a given total water use. The feasibility of rainfed barley was assessed under a wide range of climatic conditions mainly focusing on the drought years. Results show that in terms of water use sowing by mid-November is advantageous since more rainfall is generally available. In contrast, results in terms of yield, water productivity and farm economic returns, represented by EWPR, show that delaying sowing to early January and using supplemental irrigation is the best alternative for both the dry and wet years, as well as for drought years. Under water scarcity conditions, a trade-off between water use, yield and economic water productivity is advisable; thus, “mild” to “moderate” supplemental irrigation could be adopted since they are profitable but requiring appropriated irrigation management support. Furthermore, results have shown that rainfed barley is not economically feasible in drought years in the study area; however, under wet climatic conditions, rainfed barley could be adopted with caution if late sowing is practiced.
Paula Paredes; Gonçalo C. Rodrigues; Maria Do Rosário Cameira; Maria Odete Torres; Luis S. Pereira. Assessing yield, water productivity and farm economic returns of malt barley as influenced by the sowing dates and supplemental irrigation. Agricultural Water Management 2016, 179, 132 -143.
AMA StylePaula Paredes, Gonçalo C. Rodrigues, Maria Do Rosário Cameira, Maria Odete Torres, Luis S. Pereira. Assessing yield, water productivity and farm economic returns of malt barley as influenced by the sowing dates and supplemental irrigation. Agricultural Water Management. 2016; 179 ():132-143.
Chicago/Turabian StylePaula Paredes; Gonçalo C. Rodrigues; Maria Do Rosário Cameira; Maria Odete Torres; Luis S. Pereira. 2016. "Assessing yield, water productivity and farm economic returns of malt barley as influenced by the sowing dates and supplemental irrigation." Agricultural Water Management 179, no. : 132-143.
VIABILIDADE ECONÔMICA DA IRRIGAÇÃO DEFICITÁRIA EM MILHO IRRIGADO POR GOTEJAMENTO JULIANO DALCIN MARTINS 1; MIRTA TERESINHA PETRY 2; GONÇALO CALEIA RODRIGUES 3 E REIMAR CARLESSO 4 1 Instituto Federal de Educação, Ciência e Tecnologia Farroupilha (IFRS), Câmpus Ibirubá, Ibirubá, RS, [email protected] Universidade Federal de Santa Maria (UFSM), Departamento de Engenharia Rural, Santa Maria, RS, [email protected] CEER- Engenharia dos biossistemas, Instituto Superior de Agronomia, Universidade Técnica de Lisboa, Lisboa, Portugal, [email protected] Universidade Federal de Santa Maria (UFSM), Departamento de Engenharia Rural, Santa Maria, RS, [email protected] 1 RESUMO A irrigação por gotejamento é uma tecnologia que permite maior controle sobre a quantidade de água aplicada, melhorando a eficiência de seu uso na agricultura irrigada. Entretanto, apesar das inúmeras vantagens associadas à irrigação por gotejamento, a sua implantação muitas vezes é limitada pelo elevado custo de implantação e manutenção. O principal objetivo desse trabalho foi avaliar a viabilidade econômica do uso da irrigação deficitária por gotejamento na cultura do milho. Foram conduzidos dois experimentos sob uma cobertura móvel, nos anos agrícolas de 2010/11 e 2011/12. Os tratamentos foram constituídos de irrigação plena com reposição de 100% da evapotranspiração da cultura (ETc) e irrigação deficitária, com reposição da evapotranspiração da cultura de 80, 55 e 30% da ETc, durante o ano agrícola de 2010/11 e reposição de 100, 80, 65, 45 e 40% da ETc, durante o ano agrícola de 2011/12. Os resultados indicaram que as despesas com os custos fixos relacionados às linhas laterais do sistema de irrigação foram as que mais oneraram o custo final de produção, em todos os tratamentos e condições estudadas. A análise de sensibilidade demonstrou que a lucratividade da irrigação por gotejamento na cultura do milho está associada ao custo fixo anual do sistema de irrigação e do preço de comercialização do milho. Palavras-chave: Viabilidade econômica, evapotranspiração, manejo de irrigação. MARTINS. J. D.; PETRY, M. T.; RODRIGUES, G. C.;CARLESSO. R.ECONOMIC VIABILITY OF DEFICTARY DRIP IRRIGATION INIRRIGATED CORN 2 ABSTRACT Drip irrigation is a technology that allows greater control over the applied water improving the water use efficiency in the irrigated agriculture. However, despite the advantages used associated to the drip irrigation, its implantation may sometimes be limited by installation costs. The objective of this paper was to evaluate the economic feasibility of deficit irrigation using a drip system for maize plants. Two experiments were conducted under a rain out shelter, during 2010/11 and 2011/12 growing seasons. Treatments consisted of full irrigation with replacement of 100% of crop evapotranspiration (ETc) and deficit irrigation with replacement of the crop evapotranspiration at a rate of 80, 55 and 30% ETc during the 2010/11 growing season and replacement of 100, 80, 65, 45 and 40% of ETc during the 2011/12 growing season. The results indicated that expenses with fixed costs related to the lateral lines of the irrigation system were higher for all treatments and conditions studied. Sensitivity analysis shows that the profitability of drip irrigation for maize was associated with annual fixed cost of the drip irrigation system and also the maize selling price. Keywords: Economic viability, evapotranspiration, irrigation management.
Juliano Dalcin Martins; Reimar Carlesso; Mirta Teresinha Petry; Gonçalo Rodrigues. VIABILIDADE ECONÔMICA DA IRRIGAÇÃO DEFICITÁRIA EM MILHO IRRIGADO POR GOTEJAMENTO. IRRIGA 2016, 1, 150 -165.
AMA StyleJuliano Dalcin Martins, Reimar Carlesso, Mirta Teresinha Petry, Gonçalo Rodrigues. VIABILIDADE ECONÔMICA DA IRRIGAÇÃO DEFICITÁRIA EM MILHO IRRIGADO POR GOTEJAMENTO. IRRIGA. 2016; 1 (1):150-165.
Chicago/Turabian StyleJuliano Dalcin Martins; Reimar Carlesso; Mirta Teresinha Petry; Gonçalo Rodrigues. 2016. "VIABILIDADE ECONÔMICA DA IRRIGAÇÃO DEFICITÁRIA EM MILHO IRRIGADO POR GOTEJAMENTO." IRRIGA 1, no. 1: 150-165.
Luis Santos Pereira; Paula Paredes; Gonçalo Rodrigues; M. Neves. Corrigendum to “Modeling malt barley water use and evapotranspiration partitioning in two contrasting rainfall years. Assessing AquaCrop and SIMDualKc models” [Agric. Water Manag. 159 (2015) 239–254]. Agricultural Water Management 2015, 163, 408 .
AMA StyleLuis Santos Pereira, Paula Paredes, Gonçalo Rodrigues, M. Neves. Corrigendum to “Modeling malt barley water use and evapotranspiration partitioning in two contrasting rainfall years. Assessing AquaCrop and SIMDualKc models” [Agric. Water Manag. 159 (2015) 239–254]. Agricultural Water Management. 2015; 163 ():408.
Chicago/Turabian StyleLuis Santos Pereira; Paula Paredes; Gonçalo Rodrigues; M. Neves. 2015. "Corrigendum to “Modeling malt barley water use and evapotranspiration partitioning in two contrasting rainfall years. Assessing AquaCrop and SIMDualKc models” [Agric. Water Manag. 159 (2015) 239–254]." Agricultural Water Management 163, no. : 408.
Two contrasting rainfall barley seasons, dry (2012) and wet (2013), were used to parameterize and assess the performance of the SIMDualKc and AquaCrop models. Field data were obtained from malt barley cropped in a farmer’s field in Ribatejo, Portugal. SIMDualKc applies the dual crop coefficient approach for computing and partitioning crop evapotranspiration (ET), while AquaCrop uses an empirical approach to estimate potential crop transpiration (Tc) and soil evaporation (Es) depending upon the canopy cover (CC). The calibration and validation of both models was performed through comparing observed and predicted soil water content (SWC) for both seasons. The goodness-of-fit indicators were very good for SIMDualKc, with low errors of estimate (RMSE < 0.015 cm3 cm−3). AquaCrop was first parameterized for the CC curves of both years using LAI observations. When tested for SWC, indicators have shown less accuracy than SIMDualKc. The analysis focused the partition of ET into Tc and Es by both models through the analysis of the daily basal crop coefficients (Kcb) and evaporation coefficients (Ke), and the actual crop transpiration (Ta) and Es values cumulated to each crop growth stage and the season. Differences between the dry and wet year were evident, also in terms of model behavior when simulating SWC. Differences were also notable relative to the water balance terms, namely Ta and Es. Problems with estimating Kcb and Kewith AquaCrop were identified, which likely cause its less good performance in simulating SWC and impacted yield estimation. Results of assessing both models led to conclude that computation procedures used in AquaCrop for Tc, Ta and Es lead to inaccuracies that make AquaCrop less appropriate to support irrigation scheduling.
Luis Santos Pereira; Paula Paredes; Gonçalo C. Rodrigues; Manuela Neves. Modeling malt barley water use and evapotranspiration partitioning in two contrasting rainfall years. Assessing AquaCrop and SIMDualKc models. Agricultural Water Management 2015, 159, 239 -254.
AMA StyleLuis Santos Pereira, Paula Paredes, Gonçalo C. Rodrigues, Manuela Neves. Modeling malt barley water use and evapotranspiration partitioning in two contrasting rainfall years. Assessing AquaCrop and SIMDualKc models. Agricultural Water Management. 2015; 159 ():239-254.
Chicago/Turabian StyleLuis Santos Pereira; Paula Paredes; Gonçalo C. Rodrigues; Manuela Neves. 2015. "Modeling malt barley water use and evapotranspiration partitioning in two contrasting rainfall years. Assessing AquaCrop and SIMDualKc models." Agricultural Water Management 159, no. : 239-254.
Paula Paredes; Gonçalo Rodrigues; I. Alves; Luis Santos Pereira. Corrigendum to “Partitioning evapotranspiration, yield prediction and economic returns of maize under various irrigation management strategies” [Agric. Water Manage. 135 (2014) 27–39]. Agricultural Water Management 2014, 141, 84 .
AMA StylePaula Paredes, Gonçalo Rodrigues, I. Alves, Luis Santos Pereira. Corrigendum to “Partitioning evapotranspiration, yield prediction and economic returns of maize under various irrigation management strategies” [Agric. Water Manage. 135 (2014) 27–39]. Agricultural Water Management. 2014; 141 ():84.
Chicago/Turabian StylePaula Paredes; Gonçalo Rodrigues; I. Alves; Luis Santos Pereira. 2014. "Corrigendum to “Partitioning evapotranspiration, yield prediction and economic returns of maize under various irrigation management strategies” [Agric. Water Manage. 135 (2014) 27–39]." Agricultural Water Management 141, no. : 84.
Several maize field experiments, including deficit and full irrigation, were used to assess irrigation impacts on yields. The SIMDualKc water balance model was first calibrated and validated to obtain the basal crop coefficients (Kcb) and the depletion fractions for no stress (p) relative to all crop growth stages. The values 0.15, 1.15, 0.30 were obtained for, respectively, the Kcb ini, Kcb mid and Kcb end, as well as p = 0.50. The SIMDualKc model provided the partitioning of crop ET into transpiration and soil evaporation. The estimates of the actual transpiration of the maize crop under different irrigation schedules were used with the global and multiphasic Stewart's models (S1 and S2) to assess yields. A test was performed to compare the observed yield versus the models predicted yield. Good yield prediction was achieved with both S1 and S2 models; however, the S2 model performed better since it considers the distinct water stress effects at various crop growth stages. A RMSE of 1209 kg ha−1 was obtained for S2 yield estimates, which represents 6.8% of the observed average yield, while the RMSE for the S1 model represents 10%. Performance indicators relative to water productivity (WP) and the economic water productivity ratio (EWPR) were used to assess irrigation scheduling scenarios. Results show that the mild deficit scenario had the better WP. However, WP indicators are more sensitive to water use than to yield, which makes them less adequate for assessing the performance of irrigation water use at farm. Differently, when analysing scenarios under an economic perspective using full cropping costs with EWPR, deficit irrigation was ranked lower than full irrigation. This indicator shows to be more suitable to analyse economic viability of different irrigation strategies.
Paula Paredes; G.C. Rodrigues; Isabel Alves; L.S. Pereira. Partitioning evapotranspiration, yield prediction and economic returns of maize under various irrigation management strategies. Agricultural Water Management 2014, 135, 27 -39.
AMA StylePaula Paredes, G.C. Rodrigues, Isabel Alves, L.S. Pereira. Partitioning evapotranspiration, yield prediction and economic returns of maize under various irrigation management strategies. Agricultural Water Management. 2014; 135 ():27-39.
Chicago/Turabian StylePaula Paredes; G.C. Rodrigues; Isabel Alves; L.S. Pereira. 2014. "Partitioning evapotranspiration, yield prediction and economic returns of maize under various irrigation management strategies." Agricultural Water Management 135, no. : 27-39.
Deficit irrigation is often required to cope with droughts and limited water availability. However, to select an appropriate irrigation management, it is necessary to assess when economic impacts of deficit irrigation are acceptable. Thus, the main goal of this study was to evaluate economic water productivity for maize submitted to various levels of water deficits and different irrigation systems. The study was based on two different experiments conducted in Southern Brazil, one using sprinkler irrigation to supplement rainfall and the other using drip irrigation with precipitation excluded by a rainfall shelter to simulate cultivation under dry conditions. Water productivity indicators were calculated referring to: a) actual field collected data, including yields, commodity prices and production costs; and b) a sensitivity analysis to commodity prices and production costs. Alternative centre-pivot irrigation scenarios were also developed to assess their feasibility in terms of water use and productivity when irrigation is used to supplement rainfall or when rainfall is scarce. Results show that the feasibility of deficit irrigation is highly influenced by commodity prices and by the irrigation (and water) costs when the irrigation costs are a large part of the production costs. Results also show that deficit irrigation applied when rainfall is abundant is easier to implement than deficit irrigation where rainfall is very scarce, when only a mild stress is economically viable. For well-designed and managed centre-pivot systems, results confirm that adopting deficit irrigation when rainfall is scarce is less attractive than under conditions of irrigation to supplement rainfall. It could be concluded that farmers are unlikely to choose a deficit irrigation strategy unless they are facing reduced water availability for irrigation.
Gonçalo Rodrigues; Juliano D. Martins; Francisco G. Da Silva; Reimar Carlesso; Luis Santos Pereira. Modelling economic impacts of deficit irrigated maize in Brazil with consideration of different rainfall regimes. Biosystems Engineering 2013, 116, 97 -110.
AMA StyleGonçalo Rodrigues, Juliano D. Martins, Francisco G. Da Silva, Reimar Carlesso, Luis Santos Pereira. Modelling economic impacts of deficit irrigated maize in Brazil with consideration of different rainfall regimes. Biosystems Engineering. 2013; 116 (1):97-110.
Chicago/Turabian StyleGonçalo Rodrigues; Juliano D. Martins; Francisco G. Da Silva; Reimar Carlesso; Luis Santos Pereira. 2013. "Modelling economic impacts of deficit irrigated maize in Brazil with consideration of different rainfall regimes." Biosystems Engineering 116, no. 1: 97-110.
The study sought to determine the appropriate basal crop coefficients for maize through the calibration and validation of the model SIMDualKc using various treatments of maize irrigated with sprinkler and drip methods under full and deficit irrigation and cropped with organic mulch. The model computes crop evapotranspiration (ETc) using the dual crop coefficient methodology, thus separating crop transpiration, Tc, and soil evaporation, Es. Two experiments were carried out and the model was calibrated for one treatment of each experiment and validated with the remaining treatments. The corresponding results show good agreement between the simulated and observed available soil water through the season, with regression coefficients of 0.99–1.02, and the root mean square error ranging 2.0–3.3% of the total available water. The calibrated Kcb for the initial and mid-season are respectively 0.20 and 1.12; the Kcb at end season is 0.2 for grain maize and 0.8 for maize harvested for silage. Results show that the evaporation component of evapotranspiration is less than 9% of ETc for both sprinkler and drip experiments, thus indicating the suitability of using mulch for water conservation.
Juliano D. Martins; Gonçalo C. Rodrigues; Paula Paredes; Reimar Carlesso; Zanandra B. Oliveira; Alberto E. Knies; Mirta T. Petry; Luis S. Pereira. Dual crop coefficients for maize in southern Brazil: Model testing for sprinkler and drip irrigation and mulched soil. Biosystems Engineering 2013, 115, 291 -310.
AMA StyleJuliano D. Martins, Gonçalo C. Rodrigues, Paula Paredes, Reimar Carlesso, Zanandra B. Oliveira, Alberto E. Knies, Mirta T. Petry, Luis S. Pereira. Dual crop coefficients for maize in southern Brazil: Model testing for sprinkler and drip irrigation and mulched soil. Biosystems Engineering. 2013; 115 (3):291-310.
Chicago/Turabian StyleJuliano D. Martins; Gonçalo C. Rodrigues; Paula Paredes; Reimar Carlesso; Zanandra B. Oliveira; Alberto E. Knies; Mirta T. Petry; Luis S. Pereira. 2013. "Dual crop coefficients for maize in southern Brazil: Model testing for sprinkler and drip irrigation and mulched soil." Biosystems Engineering 115, no. 3: 291-310.
This study aims to assess the economic feasibility of full and deficit irrigated maize using center pivot, set sprinkler systems and drip tape systems through multicriteria analysis. Different irrigation treatments were evaluated and compared in terms of beneficial water use and physical and economical water productivity for two commodity prices and three irrigation systems scenarios applied to a medium and a large field of 5 and 32 ha respectively. Results show that deficit treatments may lead to better water productivity indicators but deficit irrigation (DI) feasibility is highly dependent on the commodity prices. Various well-designed and managed pressurized irrigation systems’ scenarios – center-pivot, set sprinkler systems and drip tape systems – were compared and ranked using multicriteria analysis. For this, three different prioritization schemes were considered, one referring to water savings, another relative to economic results, and a third one representing a balanced situation between the first two. The rankings of alternative solutions were very sensitive to the decision-maker priorities, mainly when comparing water saving and economic results because the selected alternatives were generally not common to both priority schemes. However, some of the best alternatives for the balanced priorities scheme are common to the other two, thus suggesting a possible trade-off when selecting the best alternatives. Deficit irrigation strategies also rank differently for the various scenarios considered. The study shows that deficit irrigation with exception of mild DI is generally not economically feasible. The adoption of well designed and managed irrigation systems requires consideration of priorities of farm management in terms of water saving and economic results since that some water saving solutions do not allow appropriate recover of the investment costs, particularly with DI. Basing decisions upon multicriteria analysis allows farmers and decision-makers to better select irrigation systems and related management decisions. Results also indicate that appropriate support must be given to farmers when adopting high performance but expensive irrigation systems aimed at sustainable crop profitability.
Gonçalo C. Rodrigues; Paula Paredes; José Gonçalves; Isabel Alves; Luis S. Pereira. Comparing sprinkler and drip irrigation systems for full and deficit irrigated maize using multicriteria analysis and simulation modelling: Ranking for water saving vs. farm economic returns. Agricultural Water Management 2013, 126, 85 -96.
AMA StyleGonçalo C. Rodrigues, Paula Paredes, José Gonçalves, Isabel Alves, Luis S. Pereira. Comparing sprinkler and drip irrigation systems for full and deficit irrigated maize using multicriteria analysis and simulation modelling: Ranking for water saving vs. farm economic returns. Agricultural Water Management. 2013; 126 ():85-96.
Chicago/Turabian StyleGonçalo C. Rodrigues; Paula Paredes; José Gonçalves; Isabel Alves; Luis S. Pereira. 2013. "Comparing sprinkler and drip irrigation systems for full and deficit irrigated maize using multicriteria analysis and simulation modelling: Ranking for water saving vs. farm economic returns." Agricultural Water Management 126, no. : 85-96.
This paper is the second of a two-part series, with the first part describing the SIMDualKc model, an irrigation scheduling simulation tool that employs the dual crop coefficient approach for calculating daily crop ET and then performs a water balance for a cropped soil. The model was applied, calibrated and validated for rainfed and basin irrigated maize (Coruche, Portugal), rainfed and surface irrigated wheat (Aleppo, Syria), and furrow irrigated cotton (Fergana, Central Asia). Results show good agreement between available soil water content observed in the field and that predicted by the model. Results indicate that the calibrated model does not tend to over- or underestimate available soil water over the course of a season, and that the model, prior to calibration, and using standard values for many parameters, also performed relatively well. After calibration, the average growing season maximum estimation errors were 10 mm for maize, 8 mm for winter wheat and 9 mm for cotton, i.e., respectively 3.6, 2.9 and 5.0% of total available water. Results indicate that the separation between evaporation and transpiration and the water balance calculation procedures are accurate enough for use in operational water management. The indicators used for assessing model performance show the model to accurately simulate the water balance of several crops subjected to a variety of irrigation management practices and various climate conditions. In addition, the model was applied to alternative irrigation management scenarios and related results are discussed aiming at assessing the model's ability to support the development of alternative active water management strategies.
Ricardo D. Rosa; Paula Paredes; Gonçalo C. Rodrigues; Rui M. Fernando; Isabel Alves; Luis S. Pereira; Richard G. Allen. Implementing the dual crop coefficient approach in interactive software: 2. Model testing. Agricultural Water Management 2012, 103, 62 -77.
AMA StyleRicardo D. Rosa, Paula Paredes, Gonçalo C. Rodrigues, Rui M. Fernando, Isabel Alves, Luis S. Pereira, Richard G. Allen. Implementing the dual crop coefficient approach in interactive software: 2. Model testing. Agricultural Water Management. 2012; 103 ():62-77.
Chicago/Turabian StyleRicardo D. Rosa; Paula Paredes; Gonçalo C. Rodrigues; Rui M. Fernando; Isabel Alves; Luis S. Pereira; Richard G. Allen. 2012. "Implementing the dual crop coefficient approach in interactive software: 2. Model testing." Agricultural Water Management 103, no. : 62-77.
Irrigation planning and scheduling require the availability of modeling tools that are accurate, quick and easy to use. The crop coefficient (Kc)-reference evapotranspiration (ET) method is a traditional method for estimating ET, but has become relatively complicated with the introduction of the dual Kc procedure. The dual crop coefficient approach (Kcb + Ke) gives a better estimation of daily crop evapotranspiration because it separately considers soil evaporation and crop transpiration. This approach allows one to plan irrigation schedules properly, especially in the case of crops that do not completely cover the soil, where evaporation from the soil surface may be substantial. The SIMDualKc software application was developed with the purpose of simplifying implementation of the computation of the crop coefficient and crop evapotranspiration using the dual crop coefficient approach over a range of cultural practices and to provide ET information for use in irrigation scheduling and hydrologic water balances. The model performs a soil water balance at the field level using a daily time step. It estimates crop transpiration and soil evaporation as well as soil water dynamics to support irrigation scheduling for full and incomplete cover crops. This paper is the first part of a two-part series, where the second part describes model testing and application for various crops, locations and irrigation management issues.
Ricardo D. Rosa; Paula Paredes; Gonçalo C. Rodrigues; Isabel Alves; Rui M. Fernando; Luis S. Pereira; Richard G. Allen. Implementing the dual crop coefficient approach in interactive software. 1. Background and computational strategy. Agricultural Water Management 2012, 103, 8 -24.
AMA StyleRicardo D. Rosa, Paula Paredes, Gonçalo C. Rodrigues, Isabel Alves, Rui M. Fernando, Luis S. Pereira, Richard G. Allen. Implementing the dual crop coefficient approach in interactive software. 1. Background and computational strategy. Agricultural Water Management. 2012; 103 ():8-24.
Chicago/Turabian StyleRicardo D. Rosa; Paula Paredes; Gonçalo C. Rodrigues; Isabel Alves; Rui M. Fernando; Luis S. Pereira; Richard G. Allen. 2012. "Implementing the dual crop coefficient approach in interactive software. 1. Background and computational strategy." Agricultural Water Management 103, no. : 8-24.
Teresa Paço; R.D. Rosa; Paula Paredes; Gonçalo Rodrigues; Nuno Conceição; M.I. Ferreira; Luis Santos Pereira. THE DUAL CROP COEFFICIENT APPROACH: TESTING THE SIMDUALKC MODEL WITH PEACH ORCHARD EVAPOTRANSPIRATION EDDY COVARIANCE MEASUREMENTS. Acta Horticulturae 2011, 181 -188.
AMA StyleTeresa Paço, R.D. Rosa, Paula Paredes, Gonçalo Rodrigues, Nuno Conceição, M.I. Ferreira, Luis Santos Pereira. THE DUAL CROP COEFFICIENT APPROACH: TESTING THE SIMDUALKC MODEL WITH PEACH ORCHARD EVAPOTRANSPIRATION EDDY COVARIANCE MEASUREMENTS. Acta Horticulturae. 2011; (889):181-188.
Chicago/Turabian StyleTeresa Paço; R.D. Rosa; Paula Paredes; Gonçalo Rodrigues; Nuno Conceição; M.I. Ferreira; Luis Santos Pereira. 2011. "THE DUAL CROP COEFFICIENT APPROACH: TESTING THE SIMDUALKC MODEL WITH PEACH ORCHARD EVAPOTRANSPIRATION EDDY COVARIANCE MEASUREMENTS." Acta Horticulturae , no. 889: 181-188.