Net radiation — soil heat flux relations as influenced by soil water content variations

1975 ◽  
Vol 9 (1) ◽  
pp. 113-122 ◽  
Author(s):  
S. B. Idso ◽  
J. K. Aase ◽  
R. D. Jackson
Keyword(s):  
Heat Flux ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Heat Flux ◽  
Net Radiation

Evaluation of radiant canopy temperature and soil water measurement for quantifying the contribution of shallow watertables to crop evaporation.

Soil Research ◽  
1990 ◽  
Vol 28 (6) ◽  
pp. 1013 ◽  
Author(s):  
L Mateos ◽  
WS Meyer ◽  
RCG Smith ◽  
R Sides
Keyword(s):  
Heat Flux ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Aerodynamic Resistance ◽  
Sensible Heat Flux ◽  
Canopy Temperature ◽  
Balance Model ◽  
Accurate Estimation ◽  
Clay Loam

Accurate estimation of the contribution of shallow watertables to crop water consumption is of major importance for improved irrigation practice and watertable management. A water balance model based on radiant canopy temperature estimations of crop evaporation and measurements of the change in the soil water content with a neutron probe was used to estimate the net upward flux from the watertable. The model was tested against measurements made by using two weighing lysimeters containing loam and clay loam soils, and the estimation of errors involved was analysed. The watertable in the lysimeters was maintained 1 m below the ground surface. Evaporation from a soybean crop was estimated by using an energy balance model with measured values of net radiant energy and soil heat flux. Sensible heat flux was calculated from the difference between the radiant canopy temperature and air temperature, together with an estimated aerodynamic resistance of the crop. Two sources of error were associated with the model, one due to the estimation of crop evaporation and the other due to the measurement of the change in soil water content. Errors of 0.7 and 5.1 mm per day were estimated for the first and second sources respectively. The accuracy of the method was determined by the length of the period considered and by the contribution of the watertable itself. An error of 20% was estimated when periods of 20 and 80 days were considered in the loam and clay loam soils respectively. Shorter time periods will result in larger uncertainty. The implications of the these results for watertable management are discussed.

scholarly journals Estimation of ecosystem evapotranspiration in a Robinia pseudoacacia L. plantation with the use of the eddy covariance technique and modeling approaches

2021 ◽  
Author(s):  
Nikos Markos ◽  
Kalliopi Radoglou
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Eddy Covariance ◽  
Land Surface ◽  
Robinia Pseudoacacia ◽  
Environmental Drivers ◽  
Net Radiation ◽  
Eddy Covariance Technique ◽  
Modeling Approaches

Abstract Τhe eddy covariance technique provides reliable ecosystem-level ET measurements. These measurements, when combined with models and satellite products, could offer high spatiotemporal coverage and valuable mechanistic interpretation of the underlying processes. This study address one-year eddy covariance measurements from a Robinia pseudoacacia site in Northern Greece and remote sensing products, we (a) provide a medium-term description of daily ET fluxes for a R. pseudoacacia plantation in a degraded land, (b) assess the contribution of environmental drivers (e.g., net radiation, temperature etc) on ET and (c) evaluate a simple satellite and meteorological driven model for larger-scale applications, based on the land surface water index (LSWI) and the FAO approach. R. pseudoacacia was found to have quite high water consumption, especially during leaf expansion. Net radiation and soil water content had the greatest effect on ecosystem evapotranspiration. LSWI was found to be correlated with both soil water content and evapotranspiration. Its use as an index for water limitation in models lead to high accuracy when compared to ET measurements. Our results (a) provide a significant contribution to the assessment of R. pseudoacacia ecophysiology and (b) highlight the potential of accurate ecosystem ET estimation with simple modeling approaches.

SOIL WATER CONTENT AFFECTS THE AVAILABILITY OF PHOSPHATE

1985 ◽  
pp. 185-189
Author(s):  
M.C.H.Mouat Pieter Nes
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Solution ◽  
Equivalent Reduction

Reduction in water content of a soil increased the concentration of ammonium and nitrate in solution, but had no effect on the concentration of phosphate. The corresponding reduction in the quantity of phosphate in solution caused an equivalent reduction in the response of ryegrass to applied phosphate. Keywords: soil solution, soil water content, phosphate, ryegrass, nutrition.

Effect of inter-row cultivation on soil carbon dioxide emission in a peach plantation

2010 ◽  
Vol 59 (1) ◽  
pp. 157-164 ◽  
Author(s):  
E. Tóth ◽  
Cs. Farkas
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Carbon Dioxide Emission ◽  
Nutrient Content ◽  
Soil Disturbance ◽  
Biological Properties ◽  
Soil Tillage ◽  
Favourable Effect ◽  
Volumetric Soil Water Content

Soil biological properties and CO2emission were compared in undisturbed grass and regularly disked rows of a peach plantation. Higher nutrient content and biological activity were found in the undisturbed, grass-covered rows. Significantly higher CO2fluxes were measured in this treatment at almost all the measurement times, in all the soil water content ranges, except the one in which the volumetric soil water content was higher than 45%. The obtained results indicated that in addition to the favourable effect of soil tillage on soil aeration, regular soil disturbance reduces soil microbial activity and soil CO2emission.

Evaluation of a Multi-Rod Probe Performance for Accurate Measurements of Soil Water Content

2020 ◽  
Author(s):  
Justyna Szerement ◽  
Aleksandra Woszczyk ◽  
Agnieszka Szyplowska ◽  
Marcin Kafarski ◽  
Arkadiusz Lewandowski ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content

Effects of soil water content and temperature on Bt protein degradation in leaves at thinning stage and buds of Bt cotton

2014 ◽  
Vol 22 (3) ◽  
pp. 300-307
Author(s):  
Meijun ZHANG ◽  
Wude YANG ◽  
Meichen FENG ◽  
Yun DUAN ◽  
Mingming TANG ◽  
...  
Keyword(s):  
Protein Degradation ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Bt Cotton ◽  
Bt Protein

Evapotranspiration Measurement and Irrigation Scheduling for Several Tropical Fruit Crops Using the EnviroScan System

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 549f-550
Author(s):  
Mongi Zekri ◽  
Bruce Schaffer ◽  
Stephen K. O'Hair ◽  
Roberto Nunez-Elisea ◽  
Jonathan H. Crane
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Use ◽  
National Parks ◽  
Quantitative Information ◽  
Irrigation Scheduling ◽  
Management Tool ◽  
Fruit Crops ◽  
Tropical Fruit

In southern Florida, most tropical fruit crops between Biscayne and Everglades National Parks are irrigated at rates and frequencies based on experience and observations of tree growth and fruit yield rather than on reliable quantitative information of actual water use. This approach suggests that irrigation rates may be excessive and could lead to leaching of agricultural chemicals into the groundwater in this environmentally sensitive area. Therefore, a study is being conducted to increase water use efficiency and optimize irrigation by accurately scheduling irrigation using a very effective management tool (EnviroScan, Sentek Environmental Innovations, Pty., Kent, Australia) that continuously monitors soil water content with highly accurate capacitance multi-sensor probes installed at several depths within the soil profile. The system measures crop water use by monitoring soil water depletion rates and allows the maintenance of soil water content within the optimum range (below field capacity and well above the onset of plant water stress). The study is being conducted in growers' orchards with three tropical fruit crops (avocado, carambola, and `Tahiti' lime) to facilitate rapid adoption and utilization of research results.

Laboratory Evaluation of the Dual-Probe Heat-Pulse Method for Measuring Soil Water Content

2003 ◽  
Vol 2 (3) ◽  
pp. 389
Author(s):  
J. M. Basinger ◽  
G. J. Kluitenberg ◽  
J. M. Ham ◽  
J. M. Frank ◽  
P. L. Barnes ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Pulse Method ◽  
Heat Pulse ◽  
Laboratory Evaluation ◽  
Dual Probe
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