scholarly journals AGRICULTURAL WATER BALANCE STUDY IN SINDH (PAKISTAN) USING SATELLITE-DERIVED ACTUAL EVAPOTRANSPIRATION

2020 ◽  
Author(s):  
Arjumand Zaidi ◽  
Nabeel Khan ◽  
Bakhshal Lashari ◽  
Farooq Laghari ◽  
Vengus Panhwar
Keyword(s):  
Water Balance ◽  
Actual Evapotranspiration ◽  
Agricultural Water ◽  
Balance Study

scholarly journals Assessing Annual Actual Evapotranspiration Based on Climate, Topography and Soil in Natural and Agricultural Ecosystems

Climate ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 20
Author(s):  
Kleoniki Demertzi ◽  
Vassilios Pisinaras ◽  
Emanuel Lekakis ◽  
Evangelos Tziritis ◽  
Konstantinos Babakos ◽  
...  
Keyword(s):  
Water Balance ◽  
Large Scale ◽  
Hydrological Model ◽  
Actual Evapotranspiration ◽  
Irrigated Agriculture ◽  
Climate Data ◽  
Natural Ecosystems ◽  
Loading Effects ◽  
Very High ◽  
Of Greece

Simple formulas for estimating annual actual evapotranspiration (AET) based on annual climate data are widely used in large scale applications. Such formulas do not have distinct compartments related to topography, soil and irrigation, and for this reason may be limited in basins with high slopes, where runoff is the dominant water balance component, and in basins where irrigated agriculture is dominant. Thus, a simplistic method for assessing AET in both natural ecosystems and agricultural systems considering the aforementioned elements is proposed in this study. The method solves AET through water balance based on a set of formulas that estimate runoff and percolation. These formulas are calibrated by the results of the deterministic hydrological model GLEAMS (Groundwater Loading Effects of Agricultural Management Systems) for a reference surface. The proposed methodology is applied to the country of Greece and compared with the widely used climate-based methods of Oldekop, Coutagne and Turk. The results show that the proposed methodology agrees very well with the method of Turk for the lowland regions but presents significant differences in places where runoff is expected to be very high (sloppy areas and areas of high rainfall, especially during December–February), suggesting that the proposed method performs better due to its runoff compartment. The method can also be applied in a single application considering irrigation only for the irrigated lands to more accurately estimate AET in basins with a high percentage of irrigated agriculture.

scholarly journals Hydrodynamic changes of the soil-cactus interface, effective actual evapotranspiration and its water efficiency under irrigation

2017 ◽  
Vol 21 (4) ◽  
pp. 273-278 ◽  
Author(s):  
José E. F. de Morais ◽  
Thieres G. F. da Silva ◽  
Maria G. de Queiroz ◽  
Gherman G. L. de Araújo ◽  
Magna S. B. Moura ◽  
...  
Keyword(s):  
Water Balance ◽  
Soil Water ◽  
Water Dynamics ◽  
Soil Water Balance ◽  
Actual Evapotranspiration ◽  
Water Efficiency ◽  
Economic Returns ◽  
Soil Water Dynamics ◽  
Irrigation Depth ◽  
Efficiency Indicators

ABSTRACT The knowledge on soil water dynamics is the basis of crop water management. The soil water balance (SWB) method is used for this purpose. However, its application in cactus may lead to misinterpretation in water efficiency analysis, since it does not consider the amount of water retained in the plant (WRP). This study aimed to evaluate SWB applicability, hydrodynamic changes and water efficiency of forage cactus clones under irrigation. The clones ‘Orelha de Elefante Mexicana’ (OEM), ‘IPA Sertânia’ (IPA) and ‘Miúda’ (MIU) were submitted to irrigation depths (2.5, 5.0 and 7.5 mm) and frequencies (7, 14 and 28 days), in Serra Talhada, PE, Brazil, between March 2012 and August 2013. The SWB was applied, by adding the WRP in the estimate of the effective actual evapotranspiration (ETrEF). The water efficiency indicators were calculated. The actual evapotranspiration on SWB (ETrSWB) overestimated ETrEF and, like other SWB components, it was affected by the factors irrigation depth, frequency and clone. The clone OEM is the most efficient, due to the use of the WRP, while MIU leads to highest gross economic returns for sale of cladodes as seed. As conclusion, the application of the soil water balance method in areas cultivated with cactus species must be accompanied by WRP.

Distribution and magnitude of geologic carbon sinks: a water balance study of the Chaotian River basin, Guilin, China

2015 ◽  
Vol 74 (2) ◽  
pp. 913-920
Author(s):  
Liang Li ◽  
Jianhua Cao ◽  
Fen Huang ◽  
Pei Wang ◽  
Yi Liang
Keyword(s):  
Water Balance ◽  
River Basin ◽  
Carbon Sinks ◽  
Balance Study

Modelling seasonal evapotranspiration of arid lands in China

2011 ◽  
Vol 42 (1) ◽  
pp. 40-49 ◽  
Author(s):  
Yuanrun Zheng ◽  
Zhixiao Xie ◽  
Charles Roberts ◽  
Ping An ◽  
Xiangjun Li ◽  
...  
Keyword(s):  
Water Balance ◽  
Water Resource Management ◽  
Numerical Models ◽  
Field Measurements ◽  
Western China ◽  
Actual Evapotranspiration ◽  
Climate Data ◽  
Robust Model ◽  
Proposed Model ◽  
Local Soil

The measurement of actual evapotranspiration, a key term in the water balance equation, has become a very important issue. Many good methods exist for estimating actual evapotranspiration; however, most of these require complicated inputs. Here, a simple but robust model for estimation of actual evapotranspiration in arid areas of western China is proposed. This model is a visual system with a user-friendly interface in the STELLA (a commercial software package for building numerical models) environment combined with two existing water balance equations and local soil and climate data to ensure its easy application in developing areas. Validation with field measurements revealed that the estimated values of actual evapotranspiration obtained using the model are in agreement with the observed values. Both the established Choudhury model and the proposed model produced similar estimates when the actual annual evapotranspiration is below 200 mm, but the model proposed simulates real-world conditions more precisely when the actual annual evapotranspiration is greater than 200 mm. Another advantage of the proposed model is that it uses simple and reliable climate data that are readily available from the network of weather stations in China. The simulation results could serve as a relatively good reference for water resource management in this area.

ACTUAL EVAPOTRANSPIRATION IN RELATION TO LEAF AREA

1974 ◽  
Vol 5 (3) ◽  
pp. 173-182 ◽  
Author(s):  
K. J. KRISTENSEN
Keyword(s):  
Water Balance ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Water Use ◽  
Actual Evapotranspiration ◽  
Potential Evaporation ◽  
Area Index

The ratio of leaf area to ground area required for maintaining potential evaporation has been studied in a 4-year investigation, and the influence of leaf area index on the water use and the actual water balance is discussed.

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