Estimation of crop water requirements in arid region using Penman–Monteith equation with derived crop coefficients: a case study on Acala cotton in Sudan Gezira irrigated scheme

2000 ◽  
Vol 45 (2) ◽  
pp. 203-214 ◽  
Author(s):  
A.W Abdelhadi ◽  
Takeshi Hata ◽  
Haruya Tanakamaru ◽  
Akio Tada ◽  
M.A Tariq
Keyword(s):  
Arid Region ◽  
Crop Water ◽  
Water Requirements ◽  
Crop Water Requirements ◽  
Crop Coefficients ◽  
Monteith Equation ◽  
Sudan Gezira

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 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.

Weighing Lysimeters for the Determination of Crop Water Requirements and Crop Coefficients

2006 ◽  
Vol 22 (6) ◽  
pp. 851-856 ◽  
Author(s):  
T. Marek ◽  
G. Piccinni ◽  
A. Schneider ◽  
T. Howell ◽  
M. Jett ◽  
...  
Keyword(s):  
Crop Water ◽  
Water Requirements ◽  
Crop Water Requirements ◽  
Crop Coefficients

scholarly journals Estimation of the Evapotranspiration and Crop Coefficients of Bell Pepper Using a Removable Weighing Lysimeter: A Case Study in the Southeast of Spain

2021 ◽  
Vol 13 (2) ◽  
pp. 747
Author(s):  
Laura Ávila-Dávila ◽  
José Miguel Molina-Martínez ◽  
Carlos Bautista-Capetillo ◽  
Manuel Soler-Méndez ◽  
Cruz Octavio Robles Rovelo ◽  
...  
Keyword(s):  
Research Work ◽  
Bell Pepper ◽  
Crop Water ◽  
Water Requirements ◽  
Crop Water Requirements ◽  
Food And Agriculture ◽  
Food And Agriculture Organization ◽  
Precise Knowledge ◽  
Crop Coefficients ◽  
Weighing Lysimeter

Water use efficiency is essential in semiarid regions of Spain, and it can be achieved through a precise knowledge of the real crop water requirements (CWR). The Food and Agriculture Organization of the United Nations (FAO) offers standardized crop coefficients to establish the CWR. However, these coefficients can change due to different conditions, such as climatic variations and cultivation practices. In this work, the evapotranspiration (ETClys) and crop coefficients (KClys) of bell pepper were obtained with a compact removable weighing lysimeter between February and August for two crop seasons (2019 and 2020). ETClys was determined from the water balance, and the KClys values were determined as the ratio of the crop evapotranspiration, measured on the removable weighing lysimeter, and the reference evapotranspiration. The KClys average values for the bell pepper in the initial, middle, and final stages were 0.57, 1.06, and 0.80, respectively. KC regression models were obtained as a function of the fraction thermal units, achieving a maximum correlation of 0.67 (R2). In general, the KC values obtained in this research work were lower in the initial and in the final stages and larger in the middle stage in comparison with the FAO-56 values and other research works values in semiarid conditions. The bell pepper yield increased by 7.72% in 2019 and by 3.49% in 2020 compared to the yield reported by the Ministry of the Environment and Rural and Marine Areas of the Spanish Government in 2019 and with a minimum water loss through drainage. The results in this work can help farmers to determine the crop water requirements and to improve the system efficiency in semiarid locations with similar conditions to those in the study.

Standard single and basal crop coefficients for vegetable crops, an update of FAO56 crop water requirements approach

2021 ◽  
Vol 243 ◽  
pp. 106196
Author(s):  
L.S. Pereira ◽  
P. Paredes ◽  
R. López-Urrea ◽  
D.J. Hunsaker ◽  
M. Mota ◽  
...  
Keyword(s):  
Vegetable Crops ◽  
Crop Water ◽  
Water Requirements ◽  
Crop Water Requirements ◽  
Crop Coefficients
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