scholarly journals Photosynthesis, yield, energy balance, and water‐use of intercropped maize and soybean

Plant Direct ◽  
2021 ◽  
Vol 5 (12) ◽  
Author(s):  
Elena A. Pelech ◽  
Brendan C. S. Alexander ◽  
Carl J. Bernacchi
Keyword(s):  
Energy Balance ◽  
Water Use

scholarly journals Evaluation of Evapotranspiration from Eddy Covariance Using Large Weighing Lysimeters

Agronomy ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 99 ◽  
Author(s):  
Jerry Moorhead ◽  
Gary Marek ◽  
Prasanna Gowda ◽  
Xiaomao Lin ◽  
Paul Colaizzi ◽  
...  
Keyword(s):  
Energy Balance ◽  
Eddy Covariance ◽  
Water Use ◽  
Growing Season ◽  
Irrigation Scheduling ◽  
Error Rates ◽  
Energy Balance Closure ◽  
Crop Water ◽  
Crop Water Use ◽  
Hourly Data

Evapotranspiration (ET) is an important component in the water budget and used extensively in water resources management such as water planning and irrigation scheduling. In semi-arid regions, irrigation is used to supplement limited and erratic growing season rainfall to meet crop water demand. Although lysimetery is considered the most accurate method for crop water use measurements, high-precision weighing lysimeters are expensive to build and operate. Alternatively, other measurement systems such as eddy covariance (EC) are being used to estimate crop water use. However, due to numerous explicit and implicit assumptions in the EC method, an energy balance closure problem is widely acknowledged. In this study, three EC systems were installed in a field containing a large weighing lysimeter at heights of 2.5, 4.5, and 8.5 m. Sensible heat flux (H) and ET from each EC system were evaluated against the lysimeter. Energy balance closure ranged from 64% to 67% for the three sensor heights. Results showed that all three EC systems underestimated H and consequently overestimated ET; however, the underestimation of H was greater in magnitude than the overestimation of ET. Analysis showed accuracy of ET was greater than energy balance closure with error rates of 20%–30% for half-hourly values. Further analysis of error rates throughout the growing season showed that energy balance closure and ET accuracy were greatest early in the season and larger error was found after plants reached their maximum height. Therefore, large errors associated with increased biomass may indicate unaccounted-for energy stored in the plant canopy as one source of error. Summing the half-hourly data to a daily time-step drastically reduced error in ET to 10%–15%, indicating that EC has potential for use in agricultural water management.

Surface energy balance algorithm for land-based consumption water use of different land use-cover types in arid-semiarid regions

2016 ◽  
Vol 16 (6) ◽  
pp. 1497-1513
Author(s):  
Shereif H. Mahmoud ◽  
A. A. Alazba
Keyword(s):  
Land Use ◽  
Energy Balance ◽  
Surface Energy ◽  
Water Use ◽  
Water Consumption ◽  
Surface Energy Balance ◽  
Agricultural Land ◽  
Eastern Province ◽  
Very High ◽  
Coastal Lowlands

Spatiotemporal distributions of water consumption for various land use-cover types over the Eastern province of Saudi Arabia were estimated using Surface Energy Balance Algorithm. Water consumption of various land use and cover classes shows similar seasonal dynamic trends. The spatial distribution of annual actual evapotranspiration (AET) shows low values in the Empty Quarter (231–438 mm/yr), and moderate values in the Eastern Province borders (439–731 mm/yr). Very high AET values were observed in irrigated croplands in the Northern plains, Hafar Al-Batin, the central coastal lowlands, and the southern coastal lowlands, where annual AET ranged from 732 to 1,790 mm/yr, representing the majority of the study area agricultural land. Evaporative behavior of land use-cover types indicated that irrigated cropland, which occupies 0.37% of the study area, has an average daily AET ranging from 9.2 mm/day in January to a maximum value in April (30 mm/day). Average annual water use by irrigated cropland is relatively very high and it is roughly 1,786.9 mm/yr, while water bodies, which cover 0.023% (121.2 km2) of the study area, also had relatively high mean AET (660.8 mm/yr). Overall, AET rates for irrigated cropland are much higher than for other land uses.

scholarly journals Satellite-based energy balance model to estimate seasonal evapotranspiration for irrigated sorghum: a case study from the Gezira scheme, Sudan

2008 ◽  
Vol 12 (4) ◽  
pp. 1129-1139 ◽  
Author(s):  
M. A. Bashir ◽  
T. Hata ◽  
H. Tanakamaru ◽  
A. W. Abdelhadi ◽  
A. Tada
Keyword(s):  
Energy Balance ◽  
Water Use ◽  
Remotely Sensed ◽  
Balance Model ◽  
Remotely Sensed Data ◽  
Key Factor ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Crop Coefficients ◽  
Consistent Information

Abstract. The availability of the actual water use from agricultural crops is considered as the key factor for irrigation water management, water resources planning, and water allocation. Traditionally, evapotranspiration (ET) has been calculated in the Gezira scheme as the point of reference with evapotranspiration (ETo) and crop coefficients (kc) being derived from actual measurements of soil-water balance. Recently developed, advanced energy balance models assisted in estimating the ET through the remotely sensed data. In this study Enhanced Thematic Mapper Plus (ETM+) and MODerate Resolution Imaging Spectroradiometer (MODIS) images were used to estimate the spatial distribution of the daily, monthly and seasonal ET for irrigated sorghum in the Gezira scheme, Sudan. The daily ET maps were also used to estimate kc over time and space. Results of the energy balance, based on being remotely sensed, were compared to actual measurements conducted during 2004/05 season. The seasonal actual ET values, obtained from the seven MODIS images for irrigated sorghum, were estimated at 579 mm. The values for remotely sensed kc, derived during the initial mid-season and late-season crop development stages, were 0.62, 0.85, 1.15, and 0.48, respectively. On the other hand, the values for the experimental kc during the pervious mention stages were 0.55, 0.94, 1.21 and 0.65, respectively. The estimated seasonal ET of the sorghum, derived by remotely sensed kc, was 674 mm. The Landsat data and the Free MODIS provided reliable, exhaustive, and consistent information on the water use, relevant for decision support in the Gezira scheme.

scholarly journals Determining water use of sorghum from two-source energy balance and radiometric temperatures

2011 ◽  
Vol 15 (10) ◽  
pp. 3061-3070 ◽  
Author(s):  
J. M. Sánchez ◽  
R. López-Urrea ◽  
E. Rubio ◽  
V. Caselles
Keyword(s):  
Energy Balance ◽  
Water Use ◽  
Irrigation Management ◽  
Crop Coefficient ◽  
Balance Model ◽  
Crop Water ◽  
Phenological Stages ◽  
Crop Water Use ◽  
Promising Tool ◽  
Experimental Campaign

Abstract. Estimates of surface actual evapotranspiration (ET) can assist in predicting crop water requirements. An alternative to the traditional crop-coefficient methods are the energy balance models. The objective of this research was to show how surface temperature observations can be used, together with a two-source energy balance model, to determine crop water use throughout the different phenological stages of a crop grown. Radiometric temperatures were collected in a sorghum (Sorghum bicolor) field as part of an experimental campaign carried out in Barrax, Spain, during the 2010 summer growing season. Performance of the Simplified Two-Source Energy Balance (STSEB) model was evaluated by comparison of estimated ET with values measured on a weighing lysimeter. Errors of ±0.14 mm h−1 and ±1.0 mm d−1 were obtained at hourly and daily scales, respectively. Total accumulated crop water use during the campaign was underestimated by 5%. It is then shown that thermal radiometry can provide precise crop water necessities and is a promising tool for irrigation management.

An evaluation of two inexpensive energy-balance techniques for measuring water use in flood-irrigated pecans (Carya illinoinensis)

2007 ◽  
Vol 88 (1-3) ◽  
pp. 181-191 ◽  
Author(s):  
Luke J. Simmons ◽  
Junming Wang ◽  
Ted W. Sammis ◽  
David R. Miller
Keyword(s):  
Energy Balance ◽  
Water Use ◽  
Carya Illinoinensis
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