Abhinaya Subedi | Colorado State University (original) (raw)

Papers by Abhinaya Subedi

Research paper thumbnail of Modeling a variable surface resistance (rs) for alfalfa and assessing the ASCE rs performance in the reference evapotranspiration equation

Research paper thumbnail of Hourly Alfalfa Evapotranspiration Estimation Using Variable Bulk Surface Resistance

Journal of Irrigation and Drainage Engineering

Research paper thumbnail of Preliminary Performance Evaluation of the Penman Monteith Evapotranspiration Equation in Southeastern Colorado

Accurate estimation of crop evapotranspiration (ET) is important to know how much water is requir... more Accurate estimation of crop evapotranspiration (ET) is important to know how much water is required during the growing season, to improve crop water management, to conserve soil and water resources and for water rights purposes. Various forms of semi-empirical equations have been developed to estimate crop ET. The ASCE-EWRI Standardized Penman-Monteith (PM) equation and the full version of the Penman-Monteith equation have been used in this study to estimate alfalfa ET. The ASCE-EWRI Standardized PM equation along with crop coefficients (Kc) can be used to estimate actual crop ET. The full version of the PM equation can be applied to calculate actual ET directly for unstressed crop conditions using weather and crop variables. In this study, both PM ET methods were evaluated using a monolithic precision weighing lysimeter. The research was carried out at the Colorado State University- Arkansas Valley Research Center, Rocky Ford, Colorado. Data from 2009 and 2010 from a large precisio...

Research paper thumbnail of Crop Evapotranspiration (ET) Estimation Models: A Review and Discussion of the Applicability and Limitations of ET Methods

Journal of Agricultural Science, 2015

This is a review paper on existing methodologies to calculate crop evapotranspiration (ET c ). We... more This is a review paper on existing methodologies to calculate crop evapotranspiration (ET c ). We have attempted to present all the important ET estimation procedures to date starting from the simple empirical Blaney Criddle method to the complex Shuttleworth model. The common approach to calculate ET c is to estimate a reference crop ET rate (ET ref ) using weather variables from nearby weather station, and multiplying it by an appropriate crop coefficient (K c ). Recently, there have been attempts to calculate actual crop ET (ET a ) directly without using K c . The latter method is still in the developmental phase. This study reviews the existing literature on ET estimation and identifies research needs in the current methods and technology. The extension of the Shuttleworth model for hourly time step and the validity of the Irmak and Mutibwaa model at field level for various crops would be a good milestone for the one step ET estimation. Furthermore, there are indications that the development of a new variable canopy surface resistance (r c ) model, which can be applicable for different crops at different climatic conditions, would be a good contribution in this field.

Research paper thumbnail of Dynamic Performance Evaluation of a Low Cost Load Sensor

2010 Pittsburgh, Pennsylvania, June 20 - June 23, 2010, 2010

A low cost load sensor was tested for its dynamic performance for vibrating field combine loading... more A low cost load sensor was tested for its dynamic performance for vibrating field combine loading condition for an automated soil sampler that is being designed at the University of Idaho. The sampler requires a load sensor to continuously measure the weight of the soil on board, mounted on a potato combine harvester. Two types of sensors, a low-cost load sensor (Flexiforce) and a standard load sensor were tested and their performance was evaluated. Flexiforce sensor was found to be more susceptible to external electrical noise than its expensive counterpart. However, the performance of the flexiforce was comparable to the high end load sensor after filtering the noise.

Research paper thumbnail of Crop ETEstimation Models AReview And Discussion Subedi Chavez2015

This is a review paper on existing methodologies to calculate crop evapotranspiration (ET c ). We... more This is a review paper on existing methodologies to calculate crop evapotranspiration (ET c ). We have attempted to present all the important ET estimation procedures to date starting from the simple empirical Blaney Criddle method to the complex Shuttleworth model. The common approach to calculate ET c is to estimate a reference crop ET rate (ET ref ) using weather variables from nearby weather station, and multiplying it by an appropriate crop coefficient (K c ). Recently, there have been attempts to calculate actual crop ET (ET a ) directly without using K c . The latter method is still in the developmental phase. This study reviews the existing literature on ET estimation and identifies research needs in the current methods and technology. The extension of the Shuttleworth model for hourly time step and the validity of the Irmak and Mutibwaa model at field level for various crops would be a good milestone for the one step ET estimation. Furthermore, there are indications that the development of a new variable canopy surface resistance (r c ) model, which can be applicable for different crops at different climatic conditions, would be a good contribution in this field.

Research paper thumbnail of Modeling a variable surface resistance (rs) for alfalfa and assessing the ASCE rs performance in the reference evapotranspiration equation

Research paper thumbnail of Hourly Alfalfa Evapotranspiration Estimation Using Variable Bulk Surface Resistance

Journal of Irrigation and Drainage Engineering

Research paper thumbnail of Preliminary Performance Evaluation of the Penman Monteith Evapotranspiration Equation in Southeastern Colorado

Accurate estimation of crop evapotranspiration (ET) is important to know how much water is requir... more Accurate estimation of crop evapotranspiration (ET) is important to know how much water is required during the growing season, to improve crop water management, to conserve soil and water resources and for water rights purposes. Various forms of semi-empirical equations have been developed to estimate crop ET. The ASCE-EWRI Standardized Penman-Monteith (PM) equation and the full version of the Penman-Monteith equation have been used in this study to estimate alfalfa ET. The ASCE-EWRI Standardized PM equation along with crop coefficients (Kc) can be used to estimate actual crop ET. The full version of the PM equation can be applied to calculate actual ET directly for unstressed crop conditions using weather and crop variables. In this study, both PM ET methods were evaluated using a monolithic precision weighing lysimeter. The research was carried out at the Colorado State University- Arkansas Valley Research Center, Rocky Ford, Colorado. Data from 2009 and 2010 from a large precisio...

Research paper thumbnail of Crop Evapotranspiration (ET) Estimation Models: A Review and Discussion of the Applicability and Limitations of ET Methods

Journal of Agricultural Science, 2015

This is a review paper on existing methodologies to calculate crop evapotranspiration (ET c ). We... more This is a review paper on existing methodologies to calculate crop evapotranspiration (ET c ). We have attempted to present all the important ET estimation procedures to date starting from the simple empirical Blaney Criddle method to the complex Shuttleworth model. The common approach to calculate ET c is to estimate a reference crop ET rate (ET ref ) using weather variables from nearby weather station, and multiplying it by an appropriate crop coefficient (K c ). Recently, there have been attempts to calculate actual crop ET (ET a ) directly without using K c . The latter method is still in the developmental phase. This study reviews the existing literature on ET estimation and identifies research needs in the current methods and technology. The extension of the Shuttleworth model for hourly time step and the validity of the Irmak and Mutibwaa model at field level for various crops would be a good milestone for the one step ET estimation. Furthermore, there are indications that the development of a new variable canopy surface resistance (r c ) model, which can be applicable for different crops at different climatic conditions, would be a good contribution in this field.

Research paper thumbnail of Dynamic Performance Evaluation of a Low Cost Load Sensor

2010 Pittsburgh, Pennsylvania, June 20 - June 23, 2010, 2010

A low cost load sensor was tested for its dynamic performance for vibrating field combine loading... more A low cost load sensor was tested for its dynamic performance for vibrating field combine loading condition for an automated soil sampler that is being designed at the University of Idaho. The sampler requires a load sensor to continuously measure the weight of the soil on board, mounted on a potato combine harvester. Two types of sensors, a low-cost load sensor (Flexiforce) and a standard load sensor were tested and their performance was evaluated. Flexiforce sensor was found to be more susceptible to external electrical noise than its expensive counterpart. However, the performance of the flexiforce was comparable to the high end load sensor after filtering the noise.

Research paper thumbnail of Crop ETEstimation Models AReview And Discussion Subedi Chavez2015

This is a review paper on existing methodologies to calculate crop evapotranspiration (ET c ). We... more This is a review paper on existing methodologies to calculate crop evapotranspiration (ET c ). We have attempted to present all the important ET estimation procedures to date starting from the simple empirical Blaney Criddle method to the complex Shuttleworth model. The common approach to calculate ET c is to estimate a reference crop ET rate (ET ref ) using weather variables from nearby weather station, and multiplying it by an appropriate crop coefficient (K c ). Recently, there have been attempts to calculate actual crop ET (ET a ) directly without using K c . The latter method is still in the developmental phase. This study reviews the existing literature on ET estimation and identifies research needs in the current methods and technology. The extension of the Shuttleworth model for hourly time step and the validity of the Irmak and Mutibwaa model at field level for various crops would be a good milestone for the one step ET estimation. Furthermore, there are indications that the development of a new variable canopy surface resistance (r c ) model, which can be applicable for different crops at different climatic conditions, would be a good contribution in this field.