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.

Methods to estimate irrigated reference crop evapotranspiration – a review

2012 ◽  
Vol 66 (3) ◽  
pp. 525-535 ◽  
Author(s):  
R. Kumar ◽  
M. K. Jat ◽  
V. Shankar
Keyword(s):  
Water Management ◽  
Management Practices ◽  
Reference Evapotranspiration ◽  
Irrigation Scheduling ◽  
Climatic Conditions ◽  
Water Requirement ◽  
Essential Information ◽  
Climatic Regions ◽  
Daily Water

Efficient water management of crops requires accurate irrigation scheduling which, in turn, requires the accurate measurement of crop water requirement. Irrigation is applied to replenish depleted moisture for optimum plant growth. Reference evapotranspiration plays an important role for the determination of water requirements for crops and irrigation scheduling. Various models/approaches varying from empirical to physically base distributed are available for the estimation of reference evapotranspiration. Mathematical models are useful tools to estimate the evapotranspiration and water requirement of crops, which is essential information required to design or choose best water management practices. In this paper the most commonly used models/approaches, which are suitable for the estimation of daily water requirement for agricultural crops grown in different agro-climatic regions, are reviewed. Further, an effort has been made to compare the accuracy of various widely used methods under different climatic conditions.

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 Coupling a Bat Algorithm with XGBoost to Estimate Reference Evapotranspiration in the Arid and Semiarid Regions of China

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Yixiu Han ◽  
Jianping Wu ◽  
Bingnian Zhai ◽  
Yanxin Pan ◽  
Guomin Huang ◽  
...  
Keyword(s):  
Air Temperature ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Bat Algorithm ◽  
Irrigation Scheduling ◽  
Multivariate Adaptive Regression Splines ◽  
Accurate Estimation ◽  
Agricultural Irrigation ◽  
Semiarid Regions ◽  
Arid And Semiarid

Accurate estimation of reference evapotranspiration (ETo) is key to agricultural irrigation scheduling and water resources management in arid and semiarid areas. This study evaluates the capability of coupling a Bat algorithm with the XGBoost method (i.e., the BAXGB model) for estimating monthly ETo in the arid and semiarid regions of China. Meteorological data from three stations (Datong, Yinchuan, and Taiyuan) during 1991–2015 were used to build the BAXGB model, the multivariate adaptive regression splines (MARS), and the gaussian process regression (GPR) model. Six input combinations with different sets of meteorological parameters were applied for model training and testing, which included mean air temperature (Tmean), maximum air temperature (Tmax), minimum air temperature (Tmin), wind speed (U), relative humidity (RH), and solar radiation (Rs) or extraterrestrial radiation (Ra, MJ m−2·d−1). The results indicated that BAXGB models (RMSE = 0.114–0.412 mm·d−1, MAE = 0.087–0.302 mm·d−1, and R2 = 0.937–0.996) were more accurate than either MARS (RMSE = 0.146–0.512 mm·d−1, MAE = 0.112–0.37 mm·d−1, and R2 = 0.935–0.994) or GPR (RMSE = 0.289–0.714 mm·d−1, MAE = 0.197–0.564 mm·d−1, and R2 = 0.817–0.980) model for estimating ETo. Findings of this study would be helpful for agricultural irrigation scheduling in the arid and semiarid regions and may be used as reference in other regions where accurate models for improving local water management are needed.

Water requirements of olive orchards–II: determination of crop coefficients for irrigation scheduling

2005 ◽  
Vol 24 (2) ◽  
pp. 77-84 ◽  
Author(s):  
F. Orgaz ◽  
L. Testi ◽  
F.J. Villalobos ◽  
E. Fereres
Keyword(s):  
Irrigation Scheduling ◽  
Water Requirements ◽  
Crop Coefficients

scholarly journals The GEFS-Based Daily Reference Evapotranspiration (ETo) Forecast and Its Implication for Water Management in the Southeastern United States

2014 ◽  
Vol 15 (3) ◽  
pp. 1152-1165 ◽  
Author(s):  
Di Tian ◽  
Christopher J. Martinez
Keyword(s):  
Water Management ◽  
United States ◽  
Reference Evapotranspiration ◽  
Southeastern United States ◽  
Demand Forecasting ◽  
Skill Score ◽  
Irrigation Scheduling ◽  
Forecast Skill ◽  
Ensemble Forecasts ◽  
Relative Operating Characteristic

Abstract NOAA’s second-generation retrospective forecast (reforecast) dataset was created using the currently operational Global Ensemble Forecast System (GEFS). It has the potential to accurately forecast daily reference evapotranspiration ETo and can be useful for water management. This study was conducted to evaluate daily ETo forecasts using the GEFS reforecasts in the southeastern United States (SEUS) and to incorporate the ETo forecasts into irrigation scheduling to explore the usefulness of the forecasts for water management. ETo was estimated using the Penman–Monteith equation, and ensemble forecasts were downscaled and bias corrected using a forecast analog approach. The overall forecast skill was evaluated using the linear error in probability space skill score, and the forecast in five categories (terciles and 10th and 90th percentiles) was evaluated using the Brier skill score, relative operating characteristic, and reliability diagrams. Irrigation scheduling was evaluated by water deficit WD forecasts, which were determined based on the agricultural reference index for drought (ARID) model driven by the GEFS-based ETo forecasts. All forecast skill was generally positive up to lead day 7 throughout the year, with higher skill in cooler months compared to warmer months. The GEFS reforecast improved ETo forecast skill for all lead days over the SEUS compared to the first-generation reforecast. The WD forecasts driven by the ETo forecasts showed higher accuracy and less uncertainty than the forecasts driven by climatology, indicating their usefulness for irrigation scheduling, hydrological forecasting, and water demand forecasting in the SEUS.

scholarly journals Monitoring and determination of irrigation demand in Cyprus

2013 ◽  
Vol 15 (1) ◽  
pp. 93-101 ◽  
Keyword(s):  
Water Management ◽  
Irrigation Water ◽  
Original Research ◽  
Irrigation Demand ◽  
Irrigation Water Management ◽  
Demand Models ◽  
Difficult Procedure ◽  
Increasing Demand ◽  
Sustainable Irrigation

This technical paper describes and interprets the main results of an original research project, which integrates technological tools for developing a complete system for monitoring and determining irrigation demand on a systematic basis in Cyprus. More specifically, the main contribution of this paper consists in the estimation of evapotranspiration (ET) in Cyprus and furthermore in the undertaking of the required measures for a sustainable irrigation water management in the future. The determination of ET is a very difficult procedure, since it combines various meteorological and field parameters, while quite many different estimation models have been indicated in the literature. In this case study, a wireless sensor network is proposed to act as a monitoring tool for providing measurements of the necessary parameters (meteorological, climatic and other auxiliary data required to be included in the irrigation demand models) while reflectance is being determined directly from the satellite images. Geographic Information Systems (GIS) have been used to create a database for the collected data. Taking in to account the great importance of irrigation water as a principal driver in rural development, as well as the increasing demand for irrigation water, the investigation of ways for irrigation water management is extremely valuable, especially in waterscarce areas.

scholarly journals Evapotranspiration Partition and Dual Crop Coefficients in Apple Orchard with Dwarf Stocks and Dense Planting in Arid Region, Aksu Oasis, Southern Xinjiang

Agriculture ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1167
Author(s):  
Hui Cao ◽  
Hongbo Wang ◽  
Yong Li ◽  
Abdoul Kader Mounkaila Hamani ◽  
Nan Zhang ◽  
...  
Keyword(s):  
Water Management ◽  
Water Productivity ◽  
Irrigation Schedule ◽  
Irrigation Scheduling ◽  
Apple Orchard ◽  
Irrigation Amount ◽  
Late Season ◽  
Apple Production ◽  
Crop Coefficients ◽  
Southern Xinjiang

Crop coefficients are critical to developing irrigation scheduling and improving agricultural water management in farmland ecosystems. Interest in dwarf cultivation with high density (DCHD) for apple production increases in Aksu oasis, southern Xinjiang. The lack of micro-irrigation scheduling limits apple yield and water productivity of the DCHD-cultivated orchard. A two-year experiment with the DCHD-cultivated apple (Malus × domestica ‘Royal Gala’) orchard was conducted to determine crop coefficients and evapotranspiration (ETa) with the SIMDualKc model, and to investigate apple yield and water productivity (WP) in response to different irrigation scheduling. The five levels of irrigation rate were designed as W1 of 13.5 mm, W2 of 18.0 mm, W3 of 22.5 mm, W4 of 27.0 mm, and W5 of 31.5 mm. The mean value of basal crop coefficient (Kcb) at the initial-, mid-, and late-season was 1.00, 1.30, and 0.89, respectively. The Kc-local (ETa/ET0) range for apple orchard with DCHD was 1.11–1.20, 1.33–1.43, and 1.09–1.22 at the initial, middle, and late season, respectively. ETa of apple orchard in this study ranged between 415.55–989.71 mm, and soil evaporation accounted for 13.85–29.97% of ETa. Relationships between total irrigation amount and apple yield and WP were developed, and W3 was suggested as an optimum irrigation schedule with an average apple yield of 30,540.8 kg/ha and WP of 4.45 kg/m3 in 2019–2020. The results have implications in developing irrigation schedules and improving water management for apple production in arid regions.

scholarly journals Global comparison of 20 reference evapotranspiration equations in a semi-arid region of Iran

2018 ◽  
Vol 50 (1) ◽  
pp. 282-300 ◽  
Author(s):  
Hadi Farzanpour ◽  
Jalal Shiri ◽  
Ali Ashraf Sadraddini ◽  
Slavisa Trajkovic
Keyword(s):  
Arid Region ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Irrigation Scheduling ◽  
Climatic Conditions ◽  
Accurate Estimation ◽  
Management Scenarios ◽  
Global Comparison ◽  
Semi Arid Region ◽  
Semi Arid

Abstract Accurate estimation of reference evapotranspiration (ETo) is a major task in hydrology, water resources management, irrigation scheduling and determining crop water requirement. There are many empirical equations suggested by numerous references in literature for calculating ETo using meteorological data. Some such equations have been developed for specific climatic conditions while some have been applied universally. The potential for usage of these equations depends on the availability of necessary meteorological parameters for calculating ETo in different climate conditions. The focus of the present study was a global cross-comparison of 20 ETo estimation equations using daily meteorological records of 10 weather stations (covering a period of 12 years) in a semi-arid region of Iran. Two data management scenarios, namely local and cross-station scenarios, were adopted for calibrating the applied equations against the standard FAO56-PM model. The obtained results revealed that the cross-station calibration might be a good alternative for local calibration of the ETo models when proper similar stations are used for feeding the calibration matrix.

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.

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