A Review of Evapotranspiration Measurement Models, Techniques and Methods for Open and Closed Agricultural Field Applications

Detailed knowledge of energy and mass fluxes between land and the atmosphere are necessary to monitor the climate of the land and effectively exploit it in growing agricultural commodities. One of the important surface land fluxes is evapotranspiration, which combines the process of evaporation from the soil and that of transpiration from plants, describing the movement of water vapour from the land to the atmosphere. Accurately estimating evapotranspiration in agricultural systems is of high importance for efficient use of water resources and precise irrigation scheduling operations that will lead to improved water use efficiency. This paper reviews the major mechanistic and empirical models for estimating evapotranspiration including the Penman–Monteith, Stanghellini, Priestly–Taylor, and Hargreaves and Samani models. Moreover, the major differences between the models and their underlined assumptions are discussed. The application of these models is also reviewed for both open and closed field mediums and limitations of each model are highlighted. The main parameters affecting evapotranspiration rates in greenhouse settings including aerodynamic resistance, stomatal resistance and intercepted radiation are thoroughly discussed for accurate measurement and consideration in evapotranspiration models. Moreover, this review discusses direct evapotranspiration measurements systems such as eddy covariance and gas exchange systems. Other direct measurements appertaining to specific parameters such as leaf area index and surface leaf temperature and indirect measurements such as remote sensing are also presented, which can be integrated into evapotranspiration models for adaptation depending on climate and physiological characteristics of the growing medium. This review offers important directions for the estimation of evapotranspiration rates depending on the agricultural setting and the available climatological and physiological data, in addition to experimentally based adaptation processes for ET models. It also discusses how accurate evapotranspiration measurements can optimise the energy, water and food nexus.

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Studies of grain production in Sorghum bicolor (L. Moench). VI.* Profiles of photosynthesis, illuminance and foliage arrangement. 4. Profiles of Photosynthesis, Illuminance and Foliage Arrangement

Australian Journal of Agricultural Research ◽

10.1071/ar9760035 ◽

1976 ◽

Vol 27 (1) ◽

pp. 35 ◽

Cited By ~ 8

Author(s):

KS Fischer ◽

GL Wilson

Keyword(s):

Leaf Surface ◽

Canopy Structure ◽

Light Extinction ◽

Grain Production ◽

Area Index ◽

14Co2 Uptake ◽

Total Light ◽

Intercepted Radiation ◽

Density Population ◽

Sorghum Bicolor L

Grain sorghum was grown at two population densities in the field, and photosynthetic rates compared at noon. Profiles of photosynthesis were established by combining measurements of 12CO2 exchange and 14CO2 uptake. Canopy structure and light penetration were measured. Factors responsible for the superiority of the higher density population were evaluated. Photosynthesis–radiation responses of leaves were similar between the populations and there was little difference in total light interception. The high density population had leaves which were more vertically displayed, more uniformly dispersed, smaller in both length and width, and distributed over a greater height of canopy. Light was therefore more uniformly distributed down the profile, and coefficients of light extinction were lower. Associated with this was a higher leaf area index. The overall consequence was the distribution of intercepted radiation over a larger leaf surface, at a lower illuminance and therefore a higher efficiency of photosynthetic conversion, resulting in greater total photosynthesis. ___________________ ** Part V, Aust. J. Agric. Res., 26: 31 (1975).

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Disentangling the response of forest and grassland energy exchange to heatwaves under idealized land–atmosphere coupling

Biogeosciences Discussions ◽

10.5194/bgd-11-5969-2014 ◽

2014 ◽

Vol 11 (4) ◽

pp. 5969-5995

Author(s):

C. C. van Heerwaarden ◽

A. J. Teuling

Keyword(s):

Heat Wave ◽

Heat Waves ◽

Dynamic Properties ◽

Sensible Heat Flux ◽

Early Morning ◽

Stomatal Resistance ◽

Heat Fluxes ◽

Sensible Heat ◽

Area Index ◽

Wave Conditions

Abstract. This study investigates the difference in land–atmosphere interactions between grassland and forest during typical heat wave conditions in order to understand the controversial results of Teuling et al. (2010) (T10, hereafter), who have found the systematic occurrence of higher sensible heat fluxes over forest than over grassland during heat wave conditions. With a simple, but accurate coupled land–atmosphere model, we are able to reproduce the findings of T10 for both normal summer and heat wave conditions, and to carefully explore the sensitivity of the coupled land–atmosphere system to changes in incoming radiation and early-morning temperature. Our results emphasize the importance of fast processes during the onset of heat waves, since we are able to explain the results of T10 without having to take into account changes in soil moisture. In order to disentangle the contribution of differences in several static and dynamic properties between forest and grassland, we have performed an experiment in which new land use types are created that are equal to grassland, but with one of its properties replaced by that of forest. From these, we conclude that the closure of stomata in the presence of dry air is by far the most important process in creating the different behavior of grassland and forest during the onset of a heat wave. However, we conclude that for a full explanation of the results of T10 also the other properties (albedo, roughness and the ratio of minimum stomatal resistance to leaf-area index) play an important, but indirect role; their influences mainly consist of strengthening the feedback that leads to the closure of the stomata by providing more energy that can be converted into sensible heat. The model experiment also confirms that, in line with the larger sensible heat flux, higher atmospheric temperatures occur over forest.

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Impactos das mudanças climáticas na demanda hídrica e duração do ciclo do sorgo forrageiro e feijão-caupi no estado de Pernambuco

Revista Brasileira de Geografia Física ◽

10.26848/rbgf.v8.0.p542-559 ◽

2015 ◽

Vol 8 ◽

pp. 542

Author(s):

José Edson Florentino de Morais ◽

Thieres George Freire da Silva ◽

Marcela Lúcia Barbosa ◽

Wellington Jairo da Silva Diniz ◽

Carlos André Alves de Souza ◽

...

Keyword(s):

Climate Change ◽

Relative Humidity ◽

Air Temperature ◽

Water Demand ◽

Stomatal Resistance ◽

The State ◽

Extreme Weather Events ◽

Climate Change Scenarios ◽

Area Index ◽

Forage Sorghum

O aumento na ocorrência de eventos climáticos extremos nas últimas décadas é uma forte evidência das mudanças climáticas. Em regiões Semiáridas, onde a pressão de desertificação tem se intensificado, são esperadas diminuição da disponibilidade de água e maior ocorrência de períodos seca, e, consequentemente, efeitos na resposta fisiológica das plantas. Assim, objetivou-se analisar os impactos dos cenários de mudanças climáticas sobre a duração do ciclo fenológico e a demanda de água do sorgo forrageiro e do feijão-caupi cultivados no Estado de Pernambuco. Foram utilizados os valores mensais da normal climatológica brilho solar, temperatura do ar, umidade relativa do ar e velocidade do vento de dez municípios. Considerou-se um aumento de 1,8°C (Cenário B2) e 4,0°C (Cenário A1F1) na temperatura do ar e um decréscimo de 5,0% dos valores absolutos de umidade relativa do ar, além do aumento de 22% na resistência estomática e de 4% no índice de área foliar. Com base nessas informações foram gerados três cenários: situação atual e projeções futuras para B2 e A1F1. Os resultados revelaram uma redução média de 11% (B2) e 20% (A1F1), e de 10% (B2) e 17% (A1F1) na duração do ciclo, e de 4% (B2) e 8% (A1F1), e 2% (B2) e 5% (A1F1) na demanda de água acumulada para o sorgo forrageiro e feijão-caupi, respectivamente. Conclui-se que a magnitude das reduções da duração do ciclo e a demanda de água simulada para as culturas do sorgo forrageiro e do feijão-caupi variaram espaço-temporalmente no Estado de Pernambuco com os cenários de mudanças climáticas.ABSTRACT The increase in the occurrence of extreme weather events in recent decades is a strong evidence of climate change. In semiarid regions, where the pressure of desertification has intensified, are expected to decrease in the availability of water and higher occurrence of drought periods, and, consequently, effects on physiological response of plants. Thus, the objective of analyzing the impacts of climate change scenarios on the duration of phenological cycle and water demand of forage sorghum and cowpea, grown in the State of Pernambuco. Monthly values were used normal climatological solar brightness, air temperature, relative humidity and wind speed of ten municipalities. It was considered an increase of 1.8° C (B2 Scenario) and 4.0° C (A1F1 Scenario) on air temperature and a decrease of 5.0% of the absolute values of relative humidity, in addition to the 22% increase in stomatal resistance and 4% in leaf area index. Based on this information were generated three scenarios: current situation and future projections for B2, A1F1. The results revealed an average reduction of 11% (B2) and 20% (A1F1), and 10% (B2) and 17% (A1F1) for the duration of the cycle, and 4% (B2) and 8% (A1F1), and 2% (B2) and 5% (A1F1) in accumulated water demand for forage sorghum and cowpea, respectively. It is concluded that the magnitude of the reductions in the duration of the cycle and the simulated water demand for crops of forage sorghum and cowpea ranged space-temporarily in the State of Pernambuco with climate change scenarios.

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Irrigation scheduling techniques and irrigation frequency on capsicum growth and yield

DYNA ◽

10.15446/dyna.v86n211.77678 ◽

2019 ◽

Vol 86 (211) ◽

pp. 42-48

Author(s):

Leandro Candido Gordin ◽

Ceres Duarte Guedes Cabral de Almeida ◽

José Amilton Santos Júnior ◽

Ênio Farias de França e Silva ◽

Alexsandro Claudio Dos Santos Almeida ◽

...

Keyword(s):

Irrigation Management ◽

Irrigation Scheduling ◽

Growth And Yield ◽

Irrigation Frequency ◽

Area Index ◽

Moisture Sensor ◽

Soil Moisture Sensor ◽

Soil Sensors ◽

Management Techniques ◽

Factorial Design Experiment

The present study aimed to evaluate different irrigation scheduling strategies on capsicum growth and yield inprotected environment. The experiment was carried out at the Northeastern of Brazil. Five irrigation scheduling techniques to define water depth (weighing lysimeter, Hargreaves-Samani equation, Piché evaporimeter, tensiometer and soil moisture sensor) andtwo application frequencies (F1-once a day and F2-alternating frequency) were tested. A completely randomized factorial design experiment was installed in a 5 x 2 factorial scheme, with eight replicates. It was observed that the variables stem diameter and leaf area index were influenced by the irrigation scheduling techniques, and treatments based on Hargreaves-Samani and lysimeter scheduling methods led to the lowest values. Fruit biometric parameters were significantly affected only by the Hargreaves-Samani treatment. It can be concluded that both irrigation scheduling techniques and frequencies influenced capsicum growth and yield. Furthermore, irrigation management techniques based on soil sensors caused the highest yields.

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Water and Soil Nutrient Dynamics of Huanglongbing-Affected Citrus Trees as Impacted by Ground-Applied Nutrients

Agronomy ◽

10.3390/agronomy10101485 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1485 ◽

Cited By ~ 1

Author(s):

Alisheikh A. Atta ◽

Kelly T. Morgan ◽

Said A. Hamido ◽

Davie M. Kadyampakeni ◽

Kamal A. Mahmoud

Keyword(s):

Leaf Area ◽

Sap Flow ◽

Untreated Control ◽

Soil Nutrient ◽

Irrigation Scheduling ◽

Summer Season ◽

Stem Water Potential ◽

Area Index ◽

Available N ◽

Citrus Trees

The decrease in the rate of inflow and outflow of water—and thereby the uptake of plant nutrients as the result of Huanglongbing (HLB or citrus greening)—leads to a decline in overall tree growth and the development of nutrient deficiencies in HLB-affected citrus trees. This study was conducted at the University of Florida, Southwest Florida Research and Education Center (SWFREC) near Immokalee, FL from January 2017 through December 2019. The objective of the study was to determine the effect of rootstocks, nutrient type, rate, and frequency of applications on leaf area index (LAI), water relations (stomatal conductance [gs], stem water potential [Ψw], and sap flow), soil nutrient accumulation, and dynamics under HLB-affected citrus trees. The experiment was arranged in a split-split plot design that consisted of two types of rootstocks, three nitrogen (N) rates, three soil-applied secondary macronutrients, and an untreated control replicated four times. LAI significantly increased in response to the secondary macronutrients compared with uncontrolled trees. A significantly greater gs, and thus a decline in Ψw, was a manifestation of higher sap flow per unit LA (leaf area) and moisture stress for trees budded on Swingle (Swc) than Cleopatra (Cleo) rootstocks, respectively. The hourly sap flow showed significantly less water consumption per unit LA for trees that received a full dose of Ca or Mg nutrition than Ca + Mg treated and untreated control trees. The soil nutrient concentrations were consistently higher in the topmost soil depth (0–15 cm) than the two lower soil depths (15–30 cm, 30–45 cm). Mobile nutrients: soil nitrate–nitrogen (NO3-N) and Mg2+ Mg2+, Mn2+, Zn2+, and B leached to the lower soil (15–30 cm) depth during the summer season. However, the multiple split applications of N as Best Management Practices (BMPs) and optimum irrigation scheduling based on reference evapotranspiration (ETo) maintained soil available N (ammonium nitrogen [NH4-N] and NO3-N) below 4.0 mg kg−1, which was a magnitude 2.0–4.0× less than the conventional N applications. Soil NH4-N and NO3-N leached to the two lower soil depths during the rainy summer season only when trees received the highest N rate (280 kg ha−1), suggesting a lower citrus N requirement. Therefore, 224 kg ha−1 N coupled with a full Ca or Mg dose could be the recommended rate for HLB-affected citrus trees.

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Improved Irrigation Management of Sweet Orange with Huanglongbing

HortScience ◽

10.21273/hortsci12013-17 ◽

2017 ◽

Vol 52 (6) ◽

pp. 916-921 ◽

Cited By ~ 5

Author(s):

Said A. Hamido ◽

Kelly T. Morgan ◽

Robert C. Ebel ◽

Davie M. Kadyampakeni

Keyword(s):

Soil Water ◽

Leaf Area ◽

Sweet Orange ◽

Irrigation Management ◽

Irrigation Treatment ◽

Irrigation Scheduling ◽

Water Dynamics ◽

Stem Water Potential ◽

Area Index ◽

The Impact

Because of the decline in production and negative economic effects, there is an urgent need for strategies to reduce the impact of Huanglongbing (HLB) on citrus [Citrus ×sinensis (L.) Osbeck]. The objective of this study was to evaluate the impact of different irrigation schedules on total available soil water (TAW) and water uptake characteristics of citrus trees affected by HLB in central and southwest Florida. The study was initiated in Jan. 2014 for 2 years on 5-year-old sweet orange trees located in three commercial groves at Arcadia, Avon Park, and Immokalee, FL. Each grove had three irrigation scheduling treatments including the University of Florida, Institute of Food and Agricultural Sciences (UF/IFAS) recommendations, Daily irrigation, and an Intermediate treatment. All groves received similar volumes of water per week based on evapotranspiration (ETo) reported by the Florida Automated Weather Network. Sap flow (SF) measurements were taken for two trees per treatment for at least 10 days per site (twice/year). During those periods, leaf area, leaf area index (LAI), and stem water potential (Ψ) were determined. Also, TAW was determined using drainage curve and capacitance soil moisture sensors installed at incremental soil depths of 0–15, 15–30, and 30–45 cm. Results showed significant differences in average SF, LAI, Ψ, and TAW measurements among treatments. Diurnal SF value under daily irrigation treatment increased by 91%, 51%, and 105% compared with UF/IFAS irrigation in Arcadia, Avon Park, and Immokalee, respectively. Soil water contents (WCs) under daily treatment increased by 59%, 59%, and 70% compared with UF/IFAS irrigation treatment in Arcadia, Avon Park, and Immokalee, respectively. Our results indicated that daily irrigation improved tree water dynamics compared with IFAS or Intermediate irrigation scheduling treatments and reduced tree stress with the same volume of water.

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Intercepted radiation by apple canopy can be used as a basis for irrigation scheduling

Agricultural Water Management ◽

10.1016/j.agwat.2011.01.001 ◽

2011 ◽

Vol 98 (5) ◽

pp. 886-892 ◽

Cited By ~ 21

Author(s):

I. Auzmendi ◽

M. Mata ◽

G. Lopez ◽

J. Girona ◽

J. Marsal

Keyword(s):

Irrigation Scheduling ◽

Intercepted Radiation

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Regional Model Simulations of the 2008 Drought in Southern South America Using a Consistent Set of Land Surface Properties

Journal of Climate ◽

10.1175/jcli-d-13-00463.1 ◽

2014 ◽

Vol 27 (17) ◽

pp. 6754-6778 ◽

Cited By ~ 25

Author(s):

Omar V. Müller ◽

Ernesto Hugo Berbery ◽

Domingo Alcaraz-Segura ◽

Michael B. Ek

Keyword(s):

South America ◽

Land Cover ◽

Land Surface ◽

Land Use Changes ◽

Stomatal Resistance ◽

Surface Model ◽

Severe Drought ◽

Area Index ◽

Southern South America ◽

Realistic Information

Abstract This work discusses the land surface–atmosphere interactions during the severe drought of 2008 in southern South America, which was among the most severe in the last 50 years in terms of both intensity and extent. Once precipitation returned to normal values, it took about two months for the soil moisture content and vegetation to recover. The land surface effects were examined by contrasting long-term simulations using a consistent set of satellite-derived annually varying land surface biophysical properties against simulations using the conventional land-cover types in the Weather Research and Forecasting Model–Noah land surface model (WRF–Noah). The new land-cover dataset is based on ecosystem functional properties that capture changes in vegetation status due to climate anomalies and land-use changes. The results show that the use of realistic information of vegetation states enhances the model performance, reducing the precipitation biases over the drought region and over areas of excessive precipitation. The precipitation bias reductions are attributed to the corresponding changes in greenness fraction, leaf area index, stomatal resistance, and surface roughness. The temperature simulation shows a generalized increase, which is attributable to a lower vegetation greenness and a doubling of the stomatal resistance that reduces the evapotranspiration rate. The increase of temperature has a beneficial effect toward the eastern part of the domain with a notable reduction of the bias, but not over the central region where the bias is increased. The overall results suggest that an improved representation of the surface processes may contribute to improving the predictive skill of the model system.

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Effects of Planting Density on Water Use and Productivity of Pearl Millet (Pennisetum Typhoides) Grown on Stored Water. II. Water Use, Light Interception and Dry Matter Production

Experimental Agriculture ◽

10.1017/s0014479700017786 ◽

1984 ◽

Vol 20 (3) ◽

pp. 215-224 ◽

Cited By ~ 30

Author(s):

S. N. Azam-Ali ◽

P. J. Gregory ◽

J. L. Monteith

Keyword(s):

Pearl Millet ◽

Water Use ◽

Dry Matter ◽

Dry Weight ◽

Planting Density ◽

Area Index ◽

Wide Spacing ◽

Neutron Probe ◽

Matter Production ◽

Intercepted Radiation

SUMMARYPearl millet was grown on stored water at Niamey, Niger, using three row spacings. Water extraction based on neutron probe readings was compared with crop transpiration using a porometer and allied measurements. Between 23 and 52 days after sowing, plants at the narrow and medium spacings used about 77 and 100 mm of water, respectively, and those at the wide spacing used between 59 and 75 mm. Estimates of seasonal crop evaporation from leaf resistances and from the green leaf area index (GLAI) of the crops were 103, 130 and 123 mm for the narrow, medium and wide spacings, respectively. The water use per unit of dry weight produced was similar for both narrow and medium spacings but water was used more efficiently in the wide spacing. Dry weight increased in proportion to intercepted radiation with the same efficiency (1·3 g MJ−1) irrespective of spacing.

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Development and use of a variable-speed lateral boom irrigation system to define water requirements of 11 turfgrass genotypes under field conditions

Australian Journal of Experimental Agriculture ◽

10.1071/ea05157 ◽

2007 ◽

Vol 47 (1) ◽

pp. 86 ◽

Cited By ~ 11

Author(s):

D. C. Short ◽

T. D. Colmer

Keyword(s):

Water Conservation ◽

Irrigation System ◽

Water Status ◽

Irrigation Scheduling ◽

Variable Speed ◽

Leaf Water Status ◽

Area Index ◽

Class A ◽

Irrigation Requirements ◽

Class A Pan

Improved irrigation scheduling is one strategy by which water management can be improved in turfgrass systems. The development and testing of a variable-speed lateral boom irrigation system for use in field-based irrigation trials is reported. Christiansen’s coefficient of uniformity was greater than 92% and the efficiency of irrigator discharge was greater than 90% for application depths (mm/unit land area) of 0.5–13 mm. The minimum irrigation requirements were determined for 11 turfgrass genotypes from a summer irrigation dose–response field trial that applied daily treatments of 100 (control), 80, 60, 40 and 20% of the previous day’s net evaporation measured using a US Class A pan. Responses of several shoot parameters, including clipping production, green leaf area index, leaf chlorophyll and leaf water status were evaluated to define minimum irrigation requirements for the turfgrasses. Minimum irrigation requirements (as defined by declines of 10% in several shoot responses) for C3 and C4 turfgrasses were 64–94% and 32–78% of US Class A pan, respectively. Variability in irrigation requirements within C3 or C4 types was due mainly to variations in estimates based on the different shoot parameters. The results demonstrate the opportunity for water conservation by using C4 rather than C3 turfgrasses in locations with hot dry summers (and mild winters) typical of a Mediterranean-type climate.

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