scholarly journals Estimate of the crop coefficient for Eucalyptus cultivated under irrigation during initial growth

CERNE ◽  
2013 ◽  
Vol 19 (2) ◽  
pp. 247-253 ◽  
Author(s):  
Maria Emília Borges Alves ◽  
Everardo Chartuni Mantovani ◽  
Gilberto Chohaku Sediyama ◽  
Júlio César Lima Neves
Keyword(s):  
Growth Stage ◽  
Crop Coefficient ◽  
Field Measurements ◽  
Crop Productivity ◽  
Initial Growth ◽  
Water Requirements ◽  
Mean Values ◽  
Soil Fraction ◽  
Consistent Method ◽  
Crop Coefficients

The expansion in areas planted with eucalyptus crops has raised concern about the effects these may have on water resources and existing correlations between water use and crop productivity, which calls for better understanding of water requirements by plant species. The objective of this study was to determine the water requirements of an irrigated eucalyptus crop, having the estimated dual crop coefficient (dual Kc) as a reference. Mean values found for estimated crop coefficients were 0.57, 0.13 and 0.70 for Ke, Kcb and Kc respectively during initial growth stage, and 0.01, 0.81 and 0.82 for Ke, Kcb and Kc respectively during the mid-season stage. The methodology used in this study is not intended to replace field measurements for development of Kc curves. However, it provides a consistent method to evaluate values measured while providing means for estimating variations in values of Kc according to change in the soil fraction covered by vegetation.

scholarly journals Water requirement and crop coefficients of sorghum in Apodi Plateau

2021 ◽  
Vol 25 (10) ◽  
pp. 684-688
Author(s):  
João G. A. Lima ◽  
José Espínola Sobrinho ◽  
José F. de Medeiros ◽  
Paula C. Viana ◽  
Rudah M. Maniçoba
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Irrigation Management ◽  
High Growth ◽  
Crop Coefficient ◽  
Northeastern Brazil ◽  
Crop Evapotranspiration ◽  
Water Requirements ◽  
Total Crop ◽  
Crop Coefficients

ABSTRACT Sorghum is of significant economic importance for Northeastern Brazil, since it exhibits high growth rates in regions with irregular rainfall distribution and high temperatures, and is an alternative to corn, which has greater water requirements. Despite being a traditional crop in the region, there are few studies on irrigation management in the Apodi plateau. The aim of this study was to determine the evapotranspiration of the crop and the crop coefficient (Kc) for the different stages of sorghum growth in two cycles, and establish the relationship between the Kc and the normalized difference vegetation index (NDVI) obtained by radiometry. Two weighing lysimeters were used to estimate crop evapotranspiration (ETc). Reference evapotranspiration (ETo) was estimated by the Penman-Monteith method (FAO) and the crop coefficient determined using two methodologies: simple Kc and dual Kc. Total crop evapotranspiration in the two cycles was 452 and 557 mm. The ETc value was 23% higher in the second cycle compared to the first. The maximum Kc values for the first and second cycles were 1.21 and 1.35, respectively, using the dual Kc methodology. The linear relationship found between the Kc values and the NDVI allows monitoring and estimating the water requirements of the crop.

scholarly journals Simplified Water Requirement Calculators for Fruits and Vegetables

2016 ◽  
Vol 26 (4) ◽  
pp. 530-541 ◽  
Author(s):  
Brent Rowell ◽  
Mar Lar Soe
Keyword(s):  
Drip Irrigation ◽  
Fruits And Vegetables ◽  
Canopy Cover ◽  
Crop Coefficient ◽  
Climatic Data ◽  
Vegetable Crops ◽  
Rotating Disc ◽  
Water Requirements ◽  
Water Wheel ◽  
Crop Coefficients

New users of drip irrigation in Myanmar had no idea how much water to apply to their crops with drip and could not afford tensiometers or other soil moisture monitoring tools. The concept of a simple paper calculator was born out of their need for an easy-to-use yet inexpensive tool to estimate horticultural crop water requirements. We used a generalized crop coefficient and growth stage approach together with average evapotranspiration (ET) for the vegetable crops “Water Wheel” calculator and a canopy cover approach for the tree fruit calculator. Differences among published crop coefficients are relatively small for a large number of vegetables and single coefficients were used for groups of crops without putting farmers’ crops at risk. Vegetable crops were divided into two groups based on whether water requirements during harvest remained the same as for the flowering and fruiting stage or were reduced for the harvest period. A simplified canopy cover approach was used to determine water requirements for perennial fruit, tree, and vine crops. Our faith in the ability of farmers to make their own adjustments gave us confidence to simplify ET-based water requirements and make them available in the form of simple rotating disc calculators printed in color on laminated card stock. The calculators were welcomed by our staff and enabled them to provide reasonably reliable recommendations for new users of drip irrigation. When surveyed, field staff responded that 74% of farmers they advised followed Water Wheel recommendations. Rough estimates of fruit and vegetable water requirements reached a large number of new drip users in a form they could easily understand, thereby lowering adoption barriers for an unfamiliar technology. This paper describes the Water Wheel concept and design so nonspecialists might develop their own calculators using local climatic data.

scholarly journals Reduction of predictive uncertainty in estimating irrigation water requirement through multi-model ensembles and ensemble averaging

2015 ◽  
Vol 8 (4) ◽  
pp. 1233-1244 ◽  
Author(s):  
S. Multsch ◽  
J.-F. Exbrayat ◽  
M. Kirby ◽  
N. R. Viney ◽  
H.-G. Frede ◽  
...  
Keyword(s):  
Irrigation Water ◽  
Model Uncertainty ◽  
Parametric Uncertainty ◽  
Crop Coefficient ◽  
Water Requirement ◽  
Irrigation Water Requirement ◽  
Ensemble Averaging ◽  
Water Requirements ◽  
Crop Coefficients ◽  
Model Parametric Uncertainty

Abstract. Irrigation agriculture plays an increasingly important role in food supply. Many evapotranspiration models are used today to estimate the water demand for irrigation. They consider different stages of crop growth by empirical crop coefficients to adapt evapotranspiration throughout the vegetation period. We investigate the importance of the model structural versus model parametric uncertainty for irrigation simulations by considering six evapotranspiration models and five crop coefficient sets to estimate irrigation water requirements for growing wheat in the Murray–Darling Basin, Australia. The study is carried out using the spatial decision support system SPARE:WATER. We find that structural model uncertainty among reference ET is far more important than model parametric uncertainty introduced by crop coefficients. These crop coefficients are used to estimate irrigation water requirement following the single crop coefficient approach. Using the reliability ensemble averaging (REA) technique, we are able to reduce the overall predictive model uncertainty by more than 10%. The exceedance probability curve of irrigation water requirements shows that a certain threshold, e.g. an irrigation water limit due to water right of 400 mm, would be less frequently exceeded in case of the REA ensemble average (45%) in comparison to the equally weighted ensemble average (66%). We conclude that multi-model ensemble predictions and sophisticated model averaging techniques are helpful in predicting irrigation demand and provide relevant information for decision making.

scholarly journals Estimation of crop water requirements: extending the one-step approach to dual crop coefficients

2015 ◽  
Vol 12 (5) ◽  
pp. 4933-4963 ◽  
Author(s):  
J. P. Lhomme ◽  
N. Boudhina ◽  
M. M. Masmoudi ◽  
A. Chehbouni
Keyword(s):  
Surface Resistance ◽  
Crop Coefficient ◽  
Soil Surface ◽  
Stomatal Resistance ◽  
Crop Water ◽  
Water Requirements ◽  
Crop Water Requirements ◽  
One Step ◽  
Crop Coefficients ◽  
Monteith Equation

Abstract. Crop water requirements are commonly estimated with the FAO-56 methodology based upon a "two-step" approach: first a reference evapotranspiration (ET0) is calculated from weather variables with the Penman–Monteith equation; then ET0 is multiplied by a tabulated crop-specific coefficient (Kc) to determine the water requirement (ETc) of a given crop under standard conditions. This method has been challenged to the benefit of a "one-step" approach, where crop evapotranspiration is directly calculated from a Penman–Monteith equation, its surface resistance replacing the crop coefficient. Whereas the transformation of the two-step approach into a one-step approach has been well documented when a single crop coefficient (Kc) is used, the case of dual crop coefficients (Kcb for the crop and Ke for the soil) has not been treated yet. The present paper examines this specific case. Using a full two-layer model as a reference, it is shown that the FAO-56 dual crop coefficient approach can be translated into a one-step approach based upon a modified combination equation. This equation has the basic form of the Penman–Monteith equation, but its surface resistance is calculated as the parallel sum of a foliage resistance (replacing Kcb) and a soil surface resistance (replacing Ke). We also show that the foliage resistance, which depends on leaf stomatal resistance and leaf area, can be inferred from the basal crop coefficient (Kcb) in a way similar to the Matt–Shuttleworth method.

scholarly journals Applying the FAO-56 Dual Kc Method for Irrigation Water Requirements over Large Areas of the Western U.S.

2020 ◽  
Vol 63 (6) ◽  
pp. 2059-2081
Author(s):  
Richard G. Allen ◽  
Clarence W. Robison ◽  
Justin Huntington ◽  
James L. Wright ◽  
Ayse Kilic
Keyword(s):  
Climate Change ◽  
Irrigation Water ◽  
Crop Coefficient ◽  
The State ◽  
Future Climate Change ◽  
Weather Station ◽  
Water Requirements ◽  
Wide Range ◽  
Crop Coefficients ◽  
Agricultural Areas

HighlightsThe FAO-56 dual crop coefficient procedure was applied over the entire agricultural areas of Idaho and Nevada to determine evapotranspiration (ET) and net irrigation water requirements (IWR).Basal crop coefficients were expressed as functions of normalized cumulative growing degree days.ET during dormant seasons was included in the estimates.The procedure was applied to a U.S. West-wide study of climate change effects on ET and IWR.Abstract. The FAO-56 dual crop coefficient procedure was used to determine evapotranspiration (ET) and net irrigation water requirements for all agricultural areas of the states of Idaho and Nevada and in a western U.S. study on effects of climate change on future irrigation water requirements. The products of the applications are for use by state governments for water rights management, irrigation system planning and design, wastewater application system design and review, hydrologic water balances, and groundwater modeling. The products have been used by the U.S. federal government for assessing impacts of current and future climate change on irrigation water demands. The procedure was applied to data from more than 200 weather station locations across the state of Idaho, 200 weather station locations across the state of Nevada, and eight major river basins in the western U.S. for available periods of weather records. Estimates were made over daily, monthly, and annual time intervals. Methods from FAO-56 were employed for calculating reference ET and crop coefficients (Kc), with ET calculations performed for all times of the calendar year including winter. Expressing Kc as a function of thermal-time units allowed application across a wide range of local climates and elevations. The ET estimates covered a wide range of agricultural crops grown in the western U.S. plus a number of native plant systems, including wetlands, rangeland, and riparian trees. Evaporation was estimated for three types of open-water surfaces ranging from deep reservoirs to small farm ponds. Keywords: Consumptive use, Dual crop coefficient, Evapotranspiration, FAO-56, Irrigation water requirements.

scholarly journals VARIAÇÃO SAZONAL NA EVAPOTRANSPIRAÇÃO DE PLANTAS JOVENS DE LIMA ÁCIDA ‘TAHITI’

Irriga ◽  
2006 ◽  
Vol 11 (1) ◽  
pp. 26-35 ◽  
Author(s):  
Cláudio Ricardo da Silva ◽  
José Alves Júnior ◽  
Tonny José Araújo da Silva ◽  
Marcos Vinícius Folegatti ◽  
Luis Fernando de Souza Magno Campeche
Keyword(s):  
Seasonal Variation ◽  
Seasonal Variations ◽  
Crop Coefficient ◽  
Soil Evaporation ◽  
Field Conditions ◽  
Water Requirements ◽  
Experimental Area ◽  
Acid Lime ◽  
Daily Evapotranspiration ◽  
Crop Coefficients

VARIAÇÃO SAZONAL NA EVAPOTRANSPIRAÇÃO DE PLANTAS JOVENS DE LIMA ÁCIDA ‘TAHITI’  Cláudio Ricardo da Silva1; José Alves Júnior1; Tonny José Araújo da Silva1; Marcos Vinícius Folegatti1; Luis Fernando de Souza Magno Campeche21Departamento de Engenharia Rural, Escola Superior de Agricultura Luiz de Queiróz,  Universidade de São Paulo,  Piracicaba-SP, [email protected] de Engenharia Agronômica,  Universidade Federal de Sergipe  1 RESUMO O objetivo deste trabalho foi estudar a variação sazonal diária e horária na evapotranspiração de plantas jovens de lima ácida ‘Tahiti’ sob condições de campo. O estudo foi conduzido em Piracicaba, durante o inverno de 2003 e verão de 2004. Utilizou-se um lisímetro de pesagem eletrônica de 2,7 mde diâmetro e 0,8 mde profundidade com uma planta de dois anos de idade, localizado no centro da área experimental com 322 plantas. Todas as plantas do pomar foram irrigadas por quatro gotejadores autocompensantes, inclusive a do lisímetro. Os resultados permitiram verificar que no período de verão a média da evapotranspiração da cultura (ETc) foi de 1,50 mm dia-1 decrescendo a 0,66 mm dia-1 nos meses de inverno. O coeficiente de cultivo (Kc) médio obtido foi de 0,36 e 0,22 durante o período de verão e inverno, respectivamente. A ETc máxima para o período de inverno ocorreu às 14:00 h enquanto que no verão foi às 12:00 h. Além disso, ocorreram perdas por evaporação diária noturna de 17,4 % e 13,4% da ETc para o período de inverno e verão respectivamente. A curva de evaporação do solo (Ke) foi semelhante em ambos os períodos estudados. UNITERMOS: citros, lisímetro, coeficiente de cultivo, demanda hídrica  SILVA, C. R. da; ALVES JÚNIOR, J.; SILVA, T. J. A. da; FOLEGATTI, M. V.; CAMPECHE, L. F. de S. M.; SEASONAL VARIATION IN EVAPOTRANSPIRATION OF YOUNG ‘TAHITI’ACID LIME TREES  2 ABSTRACT             The objective of this study was to investigate seasonal variations in hourly and daily evapotranspiration (ETc) of acid lime ‘Tahiti’ trees under field conditions, defining values of crop coefficients. The study was carried out in Piracicaba, Brazil, during the winter of 2003 and the summer of 2004. Aweighing lysimeter of 2.7 mdiameter and 0.8 mdepth was planted with a two-year-old tree that was located at the center of an experimental area with 322 trees. The lysimeter tree was irrigated, like others in the plot, by four pressure compensated emitters. The average ETc was 1.50 mmday-1 in the summer and dropped to 0.66 mm day-1 in winter months. The average seasonal crop coefficient (Kc) was 0.36 and 0.22 for summer and winter, respectively. The maximum Etc time was at noon in the summer and at 2 pm in the winter. Moreover, night soil evaporation represented 17.4% and 13.4% of daily ETc in winter and summer. The soil evaporation curve  (Ke) in both seasons showed similar results.  KEYWORDS: citrus, lysimeter, crop coefficient, water requirements

scholarly journals ESTIMATING WATER REQUIREMENTS OF LANDSCAPE PLANTINGS

HortScience ◽  
1992 ◽  
Vol 27 (12) ◽  
pp. 1263f-1263
Author(s):  
L.R. Costello ◽  
N.P. Matheny ◽  
J.R. Clark
Keyword(s):  
Water Use ◽  
Water Loss ◽  
Reference Evapotranspiration ◽  
Crop Coefficient ◽  
Vegetation Density ◽  
Water Requirements ◽  
Landscape Water ◽  
Crop Coefficients

Since it is unlikely that crop coefficients will be established for landscape plantings, a method to estimate landscape water requirements is proposed. By evaluating three factors that significantly influence water use-species planted, vegetation density, and site microclimate-and assigning numerical values to each, an estimate of a landscape crop coefficient (or landscape coefficient, KL) can be calculated. An estimate of evapotranspirational water loss for landscapes is then the product of the landscape coefficient multiplied by the reference evapotranspiration. This paper presents values for the above three factors and discusses the rationale for each. Examples using the landscape coefficient formula are included, as well as a discussion of special considerations relative to its use.

scholarly journals Estimation of crop water requirements: extending the one-step approach to dual crop coefficients

2015 ◽  
Vol 19 (7) ◽  
pp. 3287-3299 ◽  
Author(s):  
J. P. Lhomme ◽  
N. Boudhina ◽  
M. M. Masmoudi ◽  
A. Chehbouni
Keyword(s):  
Surface Resistance ◽  
Crop Coefficient ◽  
Soil Surface ◽  
Stomatal Resistance ◽  
Crop Water ◽  
Water Requirements ◽  
Crop Water Requirements ◽  
One Step ◽  
Crop Coefficients ◽  
Monteith Equation

Abstract. Crop water requirements are commonly estimated with the FAO-56 methodology based upon a two-step approach: first a reference evapotranspiration (ET0) is calculated from weather variables with the Penman–Monteith equation, then ET0 is multiplied by a tabulated crop-specific coefficient (Kc) to determine the water requirement (ETc) of a given crop under standard conditions. This method has been challenged to the benefit of a one-step approach, where crop evapotranspiration is directly calculated from a Penman–Monteith equation, its surface resistance replacing the crop coefficient. Whereas the transformation of the two-step approach into a one-step approach has been well documented when a single crop coefficient (Kc) is used, the case of dual crop coefficients (Kcb for the crop and Ke for the soil) has not been treated yet. The present paper examines this specific case. Using a full two-layer model as a reference, it is shown that the FAO-56 dual crop coefficient approach can be translated into a one-step approach based upon a modified combination equation. This equation has the basic form of the Penman–Monteith equation but its surface resistance is calculated as the parallel sum of a foliage resistance (replacing Kcb) and a soil surface resistance (replacing Ke). We also show that the foliage resistance, which depends on leaf stomatal resistance and leaf area, can be inferred from the basal crop coefficient (Kcb) in a way similar to the Matt–Shuttleworth method.

scholarly journals Estimatation of evapotranspiration and crop coefficient of melon cultivated in protected environment

2017 ◽  
Vol 21 (11) ◽  
pp. 758-762 ◽  
Author(s):  
Cláudia S. Lozano ◽  
Roberto Rezende ◽  
Paulo S. L. de Freitas ◽  
Tiago L. Hachmann ◽  
Fernando A. S. Santos ◽  
...  
Keyword(s):  
Water Consumption ◽  
Crop Coefficient ◽  
Initial Growth ◽  
State University ◽  
Total Water ◽  
Phenological Stages ◽  
Weather Information ◽  
Total Water Consumption ◽  
Intermediate Phases ◽  
Crop Coefficients

ABSTRACT The objective of this work was to determine the water consumption and the crop coefficient of melon in a protected environment. The experiment was conducted in a greenhouse at the Technical Center of Irrigation of the State University of Maringá, in Maringá, PR. The melon hybrid used was Sunrise and the irrigations were performed daily by drip irrigation. Crop water requirement was quantified based on its evapotranspiration directly measured through constant water table lysimeters. Weather information was collected in an automatic weather station, installed inside the protected environment, which allowed to calculate the reference evapotranspiration by the Penman-Monteith method. The total water consumption of the melon crop was 295 mm, reaching maximum crop evapotranspiration of 5.16 mm d-1. The phenological stages were shorter in the initial, growth and intermediate phases, compared with the data from FAO. The determined crop coefficients were 0.87, 1.15 and 0.64 for the initial, intermediate and final stages, respectively

scholarly journals EVAPOTRANSPIRAÇÃO, COEFICIENTE DE CULTURA E CRESCIMENTO DE CANA-DE-AÇÚCAR PLANTADA POR MUDAS PRÉ-BROTADAS E POR TOLETES

Irriga ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 517-529
Author(s):  
MARIA EDUARDA NAJM SANDRINI ◽  
ALEXANDRE BARCELLOS DALRI ◽  
ANDERSON PRATES COELHO ◽  
ROGÉRIO TEIXEIRA DE FARIA ◽  
LUIZ FABIANO PALARETTI
Keyword(s):  
Regression Analysis ◽  
Water Balance ◽  
Water Consumption ◽  
Reference Evapotranspiration ◽  
Crop Coefficient ◽  
Bare Soil ◽  
Initial Growth ◽  
Crop Evapotranspiration ◽  
Agronomic Practices ◽  
Crop Coefficients

EVAPOTRANSPIRAÇÃO, COEFICIENTE DE CULTURA E CRESCIMENTO DE CANA-DE-AÇÚCAR PLANTADA POR MUDAS PRÉ-BROTADAS E POR TOLETES   MARIA EDUARDA NAJM SANDRINI1, ALEXANDRE BARCELLOS DALRI1, ANDERSON PRATES COELHO1, ROGÉRIO TEIXEIRA DE FARIA1, LUIZ FABIANO PALARETTI1   1Departamento de Engenharia e Ciências Exatas, Faculdade de Ciências Agrárias e Veterinárias, Jaboticabal, SP, Brasil. [email protected], [email protected], [email protected], [email protected], [email protected]   1 RESUMO   Atualmente, a cana-de-açúcar apresenta diversos modos de plantio, destacando-se o plantio por mudas pré-brotadas. Esse sistema necessita de novos estudos para a recomendação adequada das práticas agronômicas, como a irrigação. Objetivou-se nesse trabalho avaliar e comparar o consumo hídrico, o coeficiente de cultura e o crescimento inicial da cana-de-açúcar plantada por mudas pré-brotadas (MPB) e por toletes. Foram definidos quatro tratamentos: cana-de-açúcar plantada por MPB e por toletes, plantio de grama batatais e solo nu, todos mantidos em lisímetros de pesagem. A evapotranspiração de referência (ETo) foi medida em lisímetros com a cultura de referência (grama). A evapotranspiração da cultura (ETc) da cana-de-açúcar plantada por MPB e toletes foi estimada por meio do balanço hídrico do solo. A estimativa dos coeficientes de cultura (Kc) foi obtida pela razão entre a ETc dos lisímetros com cana e a ETo. A comparação das variáveis entre a cana-de-açúcar plantada por MPB e por toletes foi realizada por análise de regressão. O Kc da cana-de-açúcar plantada por toletes variou de 0,86 a 2,88 e do plantio por MPB de 1,12 a 3,10. A cana-de-açúcar plantada por MPB apresenta maior consumo hídrico, coeficiente de cultura e crescimento inicial do que quando plantada por toletes.   Palavras-chave: arduino, consumo hídrico, irrigação, Kc, lisímetro de pesagem.     SANDRINI, M.E.N; DALRI, A.B.; COELHO, A.P.; FARIA, R.T. de, PALARETTI, L.F. EVAPOTRANSPIRATION, CROP COEFFICIENT AND SUGARCANE GROWTH PLANTED BY PRE-SPROUTED SEEDLINGS AND STALKS     2 ABSTRACT   Currently, the sugarcane presents several types of planting, especially the planting by pre-sprouted seedlings. This system needs new studies for the adequate recommendation of agronomic practices, such as irrigation. We aimed in this work to evaluate and compare the water consumption, crop coefficient and initial growth of sugarcane planted by pre-sprouted seedlings (PSS) and stalks. Four treatments were defined, being sugarcane planted by PSS and by stalks, bahiagrass grass and bare soil, all kept in weighing lysimeters. The reference evapotranspiration (ETo) was measured in the grass lysimeters. The crop evapotranspiration (ETc) of sugarcane planted by PSS and stalks was estimated by the water balance in the soil. The estimation of the crop coefficients (Kc) was obtained from the ratio between ETc of lysimeters with sugarcane and ETo. Comparison of the variables between planted sugarcane by PSS and by stalks was performed by regression analysis. The Kc of the sugarcane planted by stalks ranged between 0.86 to 2.88 and planting by PSS from 1.12 to 3.10. The sugarcane planted by PSS presents higher water consumption, crop coefficient and initial growth than when planted by stalks.   Keywords: arduino, water consumption, irrigation, Kc, weighing lysimeter.

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