scholarly journals Measurements of the actual evapotranspiration and crop coefficients of summer and winter seasons crops in Japan

2009 ◽  
Vol 55 (No. 3) ◽  
pp. 121-127 ◽  
Author(s):  
P. Attarod ◽  
M. Aoki
Keyword(s):  
Winter Season ◽  
Ground Surface ◽  
Crop Coefficient ◽  
Bowen Ratio ◽  
Irrigation Scheduling ◽  
Summer Season ◽  
Actual Evapotranspiration ◽  
Rye Grass ◽  
Balance Technique ◽  
Crop Coefficients

The main goal was to understand the trends of actual evapotranspiration (AET) and crop coefficient (<I>K<sub>c</sub></I>) in summer and winter seasons crops in Japan, maize, soybean, wheat and Italian rye-grass. Bowen ratio energy balance technique (BREB) was applied to measure the AET and heat flux between ground surface and atmosphere. Measurements were carried out using an automatic weather station (AWS) installed seasonally in the experimental farm of Tokyo University of Agriculture and Technology (TUAT). Penman-Monteith equation recommended by FAO was used to calculate reference crop evapotranspiration (ET<SUB>0</SUB>) and <I>K<sub>c</sub></I> was obtained from the ratio of AET to ET<SUB>0</SUB>. The results indicated that the average amount of daytime AET in the winter and summer seasons crops were approximately 2.5 and 3.5 mm, respectively monthly daytime. Daytime AET varied between 1.3 and 5.7 mm in winter season crops and between 1.4 and 6.5 mm in summer season crops. No significant differences between daily average values of AET for winter season as well as for summer season crops were found at 5% level of confidence (<I>t</I> = 0.9278, wheat and Italian rye-grass and <I>t</I> = 0.6781, soybean and maize). Average <I>K<sub>c</sub></I> values of summer season crops were found to be slightly higher than those of winter seasons crops. For planning the irrigation scheduling, it is quite necessary to understand the behaviors of AET and <I>K<sub>c</sub></I> during the growing season.

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.

scholarly journals A Novel ArcGIS Toolbox for Estimating Crop Water Demands by Integrating the Dual Crop Coefficient Approach with Multi-Satellite Imagery

Water ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 38 ◽  
Author(s):  
Juan Ramírez-Cuesta ◽  
José Mirás-Avalos ◽  
José Rubio-Asensio ◽  
Diego Intrigliolo
Keyword(s):  
Information And Communication Technologies ◽  
Mean Squared Error ◽  
Irrigation System ◽  
Crop Coefficient ◽  
Irrigation Scheduling ◽  
Irrigation Season ◽  
Agricultural Field ◽  
Crop Water ◽  
Water Demands ◽  
Crop Coefficients

Advances in information and communication technologies facilitate the application of complex models for optimizing agricultural water management. This paper presents an easy-to-use tool for determining crop water demands using the dual crop coefficient approach and remote sensing imagery. The model was developed using Python as a programming language and integrated into an ArcGIS (geographic information system) toolbox. Inputs consist of images from satellites Landsat 7 and 8, and Sentinel 2A, along with data for defining crop, weather, soil type, and irrigation system. The tool produces a spatial distribution map of the crop evapotranspiration estimates, assuming no water stress, which allows quantifying the water demand and its variability within an agricultural field with a spatial resolution of either 10 m (for Sentinel) or 30 m (for Landsat). The model was validated by comparing the estimated basal crop coefficients (Kcb) of lettuce and peach during an irrigation season with those tabulated as a reference for these crops. Good agreements between Kcb derived from both methods were obtained with a root mean squared error ranging from 0.01 to 0.02 for both crops, although certain underestimations were observed resulting from the uneven crop development in the field (percent bias of −4.74% and −1.80% for lettuce and peach, respectively). The developed tool can be incorporated into commercial decision support systems for irrigation scheduling and other applications that account for the water balance in agro-ecosystems. This tool is freely available upon request to the corresponding author.

scholarly journals Comparison of Lysimeter-Derived Crop Coefficients for Legacy and Modern Drought-Tolerant Maize Hybrids in the Texas High Plains

2020 ◽  
Vol 63 (5) ◽  
pp. 1243-1257
Author(s):  
Gary W. Marek ◽  
Thomas H. Marek ◽  
Steven R. Evett ◽  
Jourdan M. Bell ◽  
Paul D. Colaizzi ◽  
...  
Keyword(s):  
Water Use ◽  
Crop Coefficient ◽  
Irrigation Scheduling ◽  
High Plains ◽  
List Type ◽  
Season Length ◽  
Planting Dates ◽  
Corn Hybrids ◽  
Drought Tolerant ◽  
Crop Coefficients

HighlightsDaily maximum crop coefficient (Kc) values were similar for legacy hybrids and a modern drought-tolerant (DT) hybrid.Later planting dates for a DT hybrid resulted in average season lengths ~25 days shorter than those of legacy hybrids.Results illustrated the effects of environment, planting date, interannual variation in temperature, and the importance of climate-specific Kc functions.DT hybrids may be more effective at reproductive growth during periods of heat stress in semi-arid environments, although additional data are needed to support this conclusion.Abstract. Corn (Zea mays L.) is a major irrigated crop grown in the Southern High Plains including the Texas Panhandle. Irrigation from the Ogallala Aquifer is required to sustain profitable corn production in the region by supplementing inadequate and erratic rainfall. Effective irrigation scheduling works to extend limited groundwater resources by avoiding water losses associated with runoff and/or percolation below the root zone. The use of crop coefficient (Kc) and reference evapotranspiration (ETo) values to estimate daily crop water use (ETc) remains an effective scheduling tool that can complement other irrigation scheduling approaches. Both Food and Agriculture Organization (FAO-56) piecewise and curvilinear Kc values for corn are found in the literature. However, advances in corn genetics have led to questions about the applicability of Kc values developed using legacy corn hybrids to irrigation of modern drought-tolerant (DT) hybrids. Lysimeter-derived Kc values for legacy corn hybrids grown in large weighing lysimeter fields at the USDA-ARS Conservation and Production Research Laboratory at Bushland, Texas, were compared with those derived from a modern DT corn hybrid recently grown in the same fields. Results indicated that although midseason daily Kc values were similar for all hybrids, average season length was ~25 days shorter for the modern DT hybrid, characterized by a shortened initial growth period followed by more rapid increase of Kc during the development period. However, plots of Kc over thermal time illustrated that the differences in season length were likely attributable to later planting dates associated with the DT corn hybrids. Average seasonal water use was 730 and 811 mm for the legacy and modern DT hybrids, respectively (three years each), with corresponding average yields of 1.2 and 1.4 kg ha-1. Results suggest that published Kc and Kcb values developed with legacy corn hybrids remain largely applicable to modern DT corn hybrids when used with accurate estimates of effective canopy-based growth stages and climate-specific Kc functions. Keywords: Crop coefficients, Drought-tolerant, Evapotranspiration, Maize, Weighing lysimeters.

scholarly journals Determination of crop-coefficients and estimation of evapotranspiration of rapeseed using lysimeter and different reference evapotranspiration models

2021 ◽  
Vol 22 (2) ◽  
pp. 172-178
Author(s):  
ABHIJIT SARMA ◽  
KRISHNA BHARADWAJ
Keyword(s):  
Water Management ◽  
Irrigation Water ◽  
Reference Evapotranspiration ◽  
Irrigation Scheduling ◽  
Actual Evapotranspiration ◽  
Accurate Estimation ◽  
Efficient Management ◽  
Best Estimate ◽  
Crop Coefficients

Accurate estimation of evapotranspiration of rapeseed is essentially required for irrigation scheduling and water management. The present study was undertaken during 2015-16 and 2017-18 in ICR Farm, Assam Agricultural University, Jorhat to determine the crop coefficients (Kc) and estimate evapotranspiration of rapeseed using lysimeter and eight reference evapotranspiration models viz. Penman-Monteith, Advection-Aridity (Bruitsaert-Strickler), Granger-Gray, Makkink, Blaney-Criddle, Turc (1961), Hargreaves-Somani and Priestly-Tailor models. During 2015-16, the crop coefficients were developed by these models. Actual evapotranspiration was determined by three weighing type lysimeters. During 2017-18, evapotranspiration was estimated by multiplying reference evapotranspiration with Kc derived by different models and compared with actual evapotranspiration estimated by lysimeter during similar growing periods. All the models except Turc (1961) showed less than 10% deviation between actual and estimated ET. The estimated evapotranspiration using Penman-Monteith and Priestly-Tailor reference evapotranspiration recorded the lowest MAE and RMSE. The study revealed that estimated evapotranspiration using Penman-Monteith reference evapotranspiration gave the best estimate of evapotranspiration of rapeseed followed by Priestly-Tailor. The crop coefficients for initial, mid and end stages were 0.83, 1.20 and 0.65, respectively for Penman-Monteith and 0.70, 1.05 and 0.55, respectively for Priestly-Tailor.These results can be used for efficient management of irrigation water for rapeseed.

­Actual Evapotranspiration for Sugarcane Based on Bowen Ratio-Energy Balance and Soil Water Balance Models with Optimized Crop Coefficients.

2021 ◽  
Author(s):  
Suelen da Costa Faria Martins ◽  
Marcos Alex dos Santos ◽  
Gustavo Bastos Lyra ◽  
José Leonaldo Souza ◽  
Guilherme Bastos Lyra ◽  
...  
Keyword(s):  
Energy Balance ◽  
Water Balance ◽  
Soil Water ◽  
Bowen Ratio ◽  
Balance Method ◽  
Northeastern Brazil ◽  
Soil Water Balance ◽  
Actual Evapotranspiration ◽  
Crop Coefficients ◽  
Ratio Energy

Abstract Evapotranspiration is an important parameter to evaluate soil water deficit and water use efficiency, especially at places with irregularly distributed precipitation.The aim of this study was to assess the daily actual evapotranspiration (ETa) estimated by the Thornthwaite and Mather soil water balance method adapted for crops (ThM) and by the dual Kc approach with the crop coefficients optimized from inversing modeling and by the adjustment procedure suggested in FAO-56. The models comparison and optimization were performed with actual evapotranspiration determined by the Bowen ratio – energy balance method (ETβ) for sugarcane at full canopy closure grown in Alagoas State, Northeastern Brazil. The objective function of the inverse problem was defined in terms of ETβ and ETa estimated by the ThM and dual Kc method by optimizing single crop coefficient (Kc) and the basal coefficient Kcb, respectively. Both optimized Kcand Kcbwere lower than the adjusted KcFAO56, with optimized Kconly 3% less than the Kc obtained experimentally. ETa estimated by ThM and dual Kc models with optimized crop coefficients (Kc = 1.05 or Kcb = 1.00) had similar high precision (r² >0.79) and accuracy (dm>0.93 and RMSE < 0.30 mm d-1), whereas using the coefficients derived from FAO 56 overestimated ETa in both models.

scholarly journals Estimating Water Use and Irrigation Requirements of Coffee in Hawaii

1994 ◽  
Vol 119 (3) ◽  
pp. 652-657 ◽  
Author(s):  
Marco V. Gutiérrez ◽  
Frederick C. Meinzer
Keyword(s):  
Crop Coefficient ◽  
Bowen Ratio ◽  
Crop Evapotranspiration ◽  
Area Index ◽  
Canopy Development ◽  
Severe Water Deficit ◽  
Balance Technique ◽  
Irrigation Requirements ◽  
Ratio Energy ◽  
Exchange Activity

Crop evapotranspiration (ETc) was measured as evaporative heat flux from drip-irrigated coffee (Coffea arabica L. cv. Yellow Catuai) fields at different stages of canopy development using the Bowen ratio-energy balance technique. Irrigation requirements were determined by comparing the ETc values obtained against reference values (ET0) derived from a modified Penman equation, and expressed as the ETc/ET0 ratio, or crop coefficient (Kc). In 1991, the average Kc was 0.75 to 0.79 for fields containing 2- to 4-year-old plantings. This ratio was 0.58 for a field containing a 1-year-old planting. Crop coefficient was 30% lower in 1992 due to higher ET0 values and lower stomatal conductance. Measurements made between July and August and again between September and November 1991 suggested that Kc may vary seasonally. Crop transpiration (T), determined with the stem heat balance technique, comprised from 40% to 95% of ETc as the leaf area index increased from 1.4 to 6.7. Behavior of Kc and T during a 25-day soil drying-reirrigation cycle indicated that the crop was able to maintain relatively high levels of gas-exchange activity during periods of severe water deficit.

PREVALENCE OF PSEUDOINVERTA ORAIENSIS IN FRESH WATER FISH, CLARIAS BATRACHUS

2019 ◽  
Vol 25 (1) ◽  
Author(s):  
ADITYA NARAYAN
Keyword(s):  
Fresh Water ◽  
Monsoon Season ◽  
Winter Season ◽  
Uttar Pradesh ◽  
Summer Season ◽  
Clarias Batrachus ◽  
Fresh Water Fish ◽  
Water Fish

The present investigation deals with the prevalence of infection of cestode, Pseudoinverta oraiensis19 parasitizing Clarias batrachus from Bundelkhand Region (U.P.) India. The studies were recorded from different sampling stations of Bundelkhand region of Uttar Pradesh. For this study 360 fresh water fish, Clarias batrachus were examined. The incidence of infection, monsoon season (17.50%) followed by winter season (20.00%) whereas high in summer season (30.00%).

APPLICATION OF SHIFTING ASSAY OF STANDARDIZED INDIRECT AGGLUTINATION (SSIA) FOR DETECTION OF ANTIGENS OF NEWCASTLE DISEASE AND INFECTIOUS BURSAL DISEASE VIRUSES IN CHICKEN FAECES

2013 ◽  
Vol 83 (5) ◽  
Author(s):  
Phạm Hồng Sơn ◽  
Phạm Hồng Kỳ ◽  
Nguyễn Thị Lan Hương ◽  
Phạm Thị Hồng Hà
Keyword(s):  
Newcastle Disease ◽  
Winter Season ◽  
Summer Season ◽  
Infectious Bursal Disease ◽  
Infection Rates ◽  
Faecal Samples ◽  
Infectious Bursal Disease Viruses ◽  
Bursal Disease ◽  
Long Time ◽  
Higher Sensitivity

. Using the method of shifting assay of standardized indirect agglutination (SSIA), the prevalence of Newcastle disease viruses (NDV) and infectious bursal disease viruses (IBDV) in chickens reared in several districts of Thua Thien Hue province in the Spring-Summer and Fall-Winter seasons was determined. In the Spring-Summer season of 2011, about 22.3% of the chickens were infected with NDV, in which A Luoi  accounted for the highest percentage of 25% of the infected chickens and Huong Thuy  the lowest  of 18.2%. Meanwhile, 36% of the same chickens were infected with IBDV, with the highest percentage (46.66%) also in A Luoi and the lowest (30.3%) also in Huong Thuy. The intensity of NDV infection in the Spring-Summer season in A Luoi and Phu Vang was highest (GMT = 1.45), and in Huong Thuy lowest (GMT = 1.31). In addition, in the Fall-Winter season, about 46% of the chickens were infected with NDV and 46.3% with IBDV in Huong Thuy and Phu Vang – two neighbouring districts of Hue City, in which NDV was detected in 54.4% of the chickens in Huong Thuy and 33.9% in Phu Vang. In contrast, IBDV was detected in 41.9% and 52.7% of the chickens respectively in the two districts. The infection was not inter-dependent. Methodically, although the differences in the infection rates were insignificant with the accuracy of 95%, faecal samples showed higher sensitivity in SSIA analyses for both cases of NDV and IBDV infection in comparision with mouth exudates. By SSIA method, results could be read clearly with unaided eyes for a long time after the performance, and it was also proven applicable for cases of haemagglutinating viruses if proper treatments for depletion of animal RBCs’ surface agglutinins could be applied.

Annual Evapotranspiration and Crop Coefficients of Ligustrum japonica Growing in Three Container Sizes

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 512c-512
Author(s):  
R.C. Beeson
Keyword(s):  
Reference Evapotranspiration ◽  
Actual Evapotranspiration ◽  
Rooted Cuttings ◽  
Supplemental Irrigation ◽  
Mean Size ◽  
Crop Coefficients ◽  
Marketable Size

The objective of this study was to determine crop coefficients (KC) for Ligustrum japonica growing in three container sizes using the Penman equation to calculate reference evapotranspiration (ETR). Rooted cuttings were transplanted into 3-liter containers and upcanned as needed into 10- and 23-L containers. Production was scheduled such that a series of plants in each container size were about 2 months from commercial marketable size every 4 months. Beginning 1 Jan. 1995 until 31 Dec. 1996, three uniform plants of each size were suspended in weighing lysimeters and surrounded by similar size plants filling an area 3.7 by 4.9 m. Plants within each area were overhead irrigated at 2000 h as needed, based on a 30% moisture allowed deficit. Plants were exchanged every 4 months such that the annual mean size was that of a marketable plant. Actual evapotranspiration (ETA) was calculated from half-hour measurements of each plant's weight and adjusted for rainfall. From these and daily calculated ETR, KC were determined for each size of container. KCs ranged from 1.06 to 1.50 when ETA was converted to mm/day based on allocated bed space. Comparisons of volumes of supplemental irrigation to ETA and effects of assumptions required in converting ETA to mm/day will be discussed.

scholarly journals THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF SUGAR CANE (SACCHARUM OFFICINARUM): A REVIEW

2011 ◽  
Vol 47 (1) ◽  
pp. 1-25 ◽  
Author(s):  
M. K. V. CARR ◽  
J. W. KNOX
Keyword(s):  
Water Stress ◽  
Water Relations ◽  
Sugar Cane ◽  
Root Zone ◽  
Water Productivity ◽  
Crop Coefficient ◽  
Saccharum Officinarum ◽  
Irrigation Scheduling ◽  
Background Information ◽  
Technology Choice

SUMMARYThe results of research on the water relations and irrigation needs of sugar cane are collated and summarized in an attempt to link fundamental studies on crop physiology to irrigation practices. Background information on the centres of production of sugar cane is followed by reviews of (1) crop development, including roots; (2) plant water relations; (3) crop water requirements; (4) water productivity; (5) irrigation systems and (6) irrigation scheduling. The majority of the recent research published in the international literature has been conducted in Australia and southern Africa. Leaf/stem extension is a more sensitive indicator of the onset of water stress than stomatal conductance or photosynthesis. Possible mechanisms by which cultivars differ in their responses to drought have been described. Roots extend in depth at rates of 5–18 mm d−1 reaching maximum depths of > 4 m in ca. 300 d providing there are no physical restrictions. The Penman-Monteith equation and the USWB Class A pan both give good estimates of reference crop evapotranspiration (ETo). The corresponding values for the crop coefficient (Kc) are 0.4 (initial stage), 1.25 (peak season) and 0.75 (drying off phase). On an annual basis, the total water-use (ETc) is in the range 1100–1800 mm, with peak daily rates of 6–15 mm d−1. There is a linear relationship between cane/sucrose yields and actual evapotranspiration (ETc) over the season, with slopes of about 100 (cane) and 13 (sugar) kg (ha mm)−1 (but variable). Water stress during tillering need not result in a loss in yield because of compensatory growth on re-watering. Water can be withheld prior to harvest for periods of time up to the equivalent of twice the depth of available water in the root zone. As alternatives to traditional furrow irrigation, drag-line sprinklers and centre pivots have several advantages, such as allowing the application of small quantities of water at frequent intervals. Drip irrigation should only be contemplated when there are well-organized management systems in place. Methods for scheduling irrigation are summarized and the reasons for their limited uptake considered. In conclusion, the ‘drivers for change’, including the need for improved environmental protection, influencing technology choice if irrigated sugar cane production is to be sustainable are summarized.

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