THREE YEARS OF EVAPOTRANSPIRATION AT TORONTO

An experiment to measure the daily potential evapotranspiration from vegetation-covered soil surfaces was conducted in Toronto during the 1947, 1948, and 1949 growing seasons. The potential evaporation from moist bare soil was also measured and compared with the evaporation from dry soil. Results indicate that the Thornthwaite formula for computing potential water loss is valid at this latitude for both vegetation-covered and moist soil. When drying of the surface soil occurred, the water loss was diminished.

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WATER UPTAKE BY ORCHARDGRASS AND EVAPORATION FROM BARE SOIL IN THE PRESENCE OF SHALLOW WATER TABLES

Canadian Journal of Soil Science ◽

10.4141/cjss68-038 ◽

1968 ◽

Vol 48 (3) ◽

pp. 281-288

Author(s):

J. C. van Schaik ◽

K. K. Krogman

Keyword(s):

Shallow Water ◽

Water Uptake ◽

Salt Concentration ◽

Surface Soil ◽

Potential Evapotranspiration ◽

Growing Season ◽

Bare Soil ◽

Water Tables

Lysimeter studies in 1967 showed that evapotranspiration by orchardgrass from June 16 to September 15 was 38.8, 37.2, and 34.9 cm with water tables at depths of 91, 122, and 152 cm. This amounted to about 60% of the potential evapotranspiration and was nearly all due to transpiration. Evaporation from a bare soil in 1967 was not high enough to influence salt concentration of the surface soil. Most salinization of the cropped soil is expected to occur outside the growing season, if the water tables do not fluctuate.

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Shallow groundwater effect on land surface temperature and surface energy balance under bare soil conditions: modeling and description

Hydrology and Earth System Sciences ◽

10.5194/hess-16-1817-2012 ◽

2012 ◽

Vol 16 (7) ◽

pp. 1817-1831 ◽

Cited By ~ 16

Author(s):

F. Alkhaier ◽

G. N. Flerchinger ◽

Z. Su

Keyword(s):

Energy Balance ◽

Surface Temperature ◽

Land Surface ◽

Shallow Groundwater ◽

Bare Soil ◽

Heat Fluxes ◽

Shortwave Radiation ◽

Soil Conditions ◽

Potential Evaporation ◽

Available Energy

Abstract. Understanding when and how groundwater affects surface temperature and energy fluxes is significant for utilizing remote sensing in groundwater studies and for integrating aquifers within land surface models. To investigate the shallow groundwater effect under bare soil conditions, we numerically exposed two soil profiles to identical metrological forcing. One of the profiles had shallow groundwater. The different responses that the two profiles manifested were inspected regarding soil moisture, temperature and energy balance at the land surface. The findings showed that the two profiles differed in three aspects: the absorbed and emitted amounts of energy, the portioning out of the available energy and the heat fluency in the soil. We concluded that due to their lower albedo, shallow groundwater areas reflect less shortwave radiation and consequently get a higher magnitude of net radiation. When potential evaporation demand is sufficiently high, a large portion of the energy received by these areas is consumed for evaporation. This increases the latent heat flux and reduces the energy that could have heated the soil. Consequently, lower magnitudes of both sensible and ground heat fluxes are caused to occur. The higher soil thermal conductivity in shallow groundwater areas facilitates heat transfer between the top soil and the subsurface, i.e. soil subsurface is more thermally connected to the atmosphere. For the reliability of remote sensors in detecting shallow groundwater effect, it was concluded that this effect can be sufficiently clear to be detected if at least one of the following conditions occurs: high potential evaporation and high contrast between day and night temperatures. Under these conditions, most day and night hours are suitable for shallow groundwater depth detection.

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The Influence of Soil Moisture and Soil Type on the Oviposition Behaviour of the Migratory Grasshopper, Melanoplus sanguinipes (Fabricius)

The Canadian Entomologist ◽

10.4039/ent97401-4 ◽

1965 ◽

Vol 97 (4) ◽

pp. 401-409 ◽

Cited By ~ 6

Author(s):

Roy L. Edwards ◽

Henry T. Epp

Keyword(s):

Soil Moisture ◽

Free Choice ◽

Melanoplus Sanguinipes ◽

Moist Soil ◽

Moist Sand ◽

Subsurface Soil ◽

Water Ph ◽

Dry Soil ◽

Oviposition Sites ◽

Different Soils

Abstract Three different soils – sand, loam and clay – at each of three moisture levels – saturated, intermediate, and dry – were offered to female Melanoplus sanguinipes as oviposition sites. When given a free choice the females preferred moist sand to all other oviposition sites and avoided soil that was completely dry. When no moist soil was available, coarse dry soil was preferred to fine dry soil, but the oviposition rate was reduced. The females would probe and dig at random into any of the soil offered but would withhold their eggs temporarily if the subsurface soil was not moist. Soil water pH appeared to have very little influence on the females' acceptance of an oviposition site as egg pods were deposited in soils with a range of pH from 3.0 to 11.6. It is suggested that although the absence of moisture in the soil may affect the distribution of egg-pods in the microhabitat and may reduce the rate of egg-pod production slightly, the temperature prevailing during the oviposition period is perhaps a more important factor in determining the number of egg-pods deposited.

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Soil solarisation combined with low rates of soil fumigants controls clubroot of cauliflowers, caused by Plasmodiophora brassicae Woron

Australian Journal of Experimental Agriculture ◽

10.1071/ea9910843 ◽

1991 ◽

Vol 31 (6) ◽

pp. 843 ◽

Cited By ~ 8

Author(s):

IJ Porter ◽

PR Merriman ◽

PJ Keane

Keyword(s):

Population Density ◽

Water Content ◽

Methyl Bromide ◽

Plasmodiophora Brassicae ◽

Moist Soil ◽

Combined Treatments ◽

Disease Rating ◽

Dry Soil ◽

Type Water ◽

Soil Fumigants

The effect of solarisation combined with low rates of soil fumigants on the severity of clubroot and yield of cauliflowers was determined at 2 locations in southern Victoria. The effectiveness of treatments was shown to be dependent on location; on the type, water content and temperature of soil; and on the population density of Plasmodiophora brassicae. Yields were reduced depending upon the disease severity, usually within 60 days after transplanting. Propagules of P. brassicae could survive for more than 28 days in ovens at 45�C when in dry soil but died within 14 days at 40�C in moist soil. At Werribee in 1985 on a red brown earth, solarisation combined with dazomet (100 kg dazomet/ha) gave significantly better control than either treatment alone. This treatment reduced P. brassicae in the 0-10 cm layer, reduced the disease rating from 2.7 to 0.9 (0-3), and increased yield from 2.4 to 47 t/ha compared with controls. In 1986, solarisation combined with 98% methyl bromide-2% chloropicrin (100 and 250 kg/ha) reduced the population density of P. brassicae in the 0-10 and 10-20 cm layers of soil, reduced the disease rating from 3 to 1.8, and increased yield from 0 to 22 t/ha. These treatments were more effective than solarisation and dazomet used alone or in combination. At Keysborough in 1985 on a grey sand, separate treatments of solarisation or dazomet (100 and 250 kg dazometha) were as effective as combined treatments and significantly reduced disease and increased yields compared to controls. Solarisation combined with either fumigant significantly reduced the distribution and total number of weeds at all sites and was generally more effective than separate treatments.

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COMPUTER ASSISTED MAPPING OF SOIL EROSION POTENTIAL

Canadian Journal of Soil Science ◽

10.4141/cjss85-045 ◽

1985 ◽

Vol 65 (3) ◽

pp. 411-418 ◽

Cited By ~ 3

Author(s):

T. VOLD ◽

M. W. SONDHEIM ◽

N. K. NAGPAL

Keyword(s):

Soil Erosion ◽

Soil Loss ◽

Surface Soil ◽

Mineral Soil ◽

Weighted Average ◽

Bare Soil ◽

Computer Assisted ◽

Additional Information ◽

Potential Map ◽

Fraser Valley

Soil erosion potential maps and summary statistics can be produced from existing information with relative ease with the aid of computers. Soil maps are digitized and survey information is stored as attributes for each soil. Algorithms are then prepared which evaluate the appropriate data base attributes (e.g. texture, slope) for each interpretation. Forty surface soil erosion potential maps were produced for the Lower Fraser Valley which identify the most erosion-prone areas and indicate average potential soil losses to be expected under assumed conditions. The algorithm developed follows the universal soil loss equation. Differences across the landscape in the R, K, and S factors are taken into account whereas the L factor is considered as a constant equal to 1.0. Worst conditions of bare soil (no crop cover, i.e. C = 1.0) and no erosion control practices (i.e. P = 1.0) are assumed. The five surface soil erosion potential classes are determined by a weighted average annual soil loss value based both on the upper 20 cm of mineral soil and on the proportion of the various soils in the polygon. A unique polygon number shown on the erosion potential map provides a link to computer tables which give additional information for each individual soil within that polygon. Key words: Erosion, computer mapping, USLE

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Effect of soil drought on evapotranspiration of a young spruce forest

Journal of Forest Science ◽

10.17221/11871-jfs ◽

2019 ◽

Vol 48 (No. 4) ◽

pp. 166-172 ◽

Cited By ~ 2

Author(s):

F. Matejka ◽

J. Rožnovský ◽

T. Hurtalová ◽

D. Janouš

Keyword(s):

Water Regime ◽

Model Simulation ◽

Global Radiation ◽

Forest Stand ◽

Soil Drought ◽

Transfer Model ◽

Moist Soil ◽

Dry Period ◽

Soil Desiccation ◽

Dry Soil

Daily courses of the actual transpiration of a forest stand were determined by an experimentally verified mathematical Soil – Vegetation – Atmosphere Transfer model. The results refer to the Norway spruce (Picea abies [L.] Karst.) monoculture situated in the highest locations of the Beskids Mts. Drought-free transpiration was estimated as a model simulation run for nonlimiting soil moisture exceeding the level of decreased availability of water. Drought-induced reduction in transpiration was quantified as a difference between actual transpiration and simulated transpiration for moist soil. The results led to conclusions that dry soil causes a significant reduction in actual evapotranspiration and its components in comparison with moist soil. Simultaneously, the effect of soil desiccation was compensated by extremely high evaporative demands of the atmosphere, so that the daily totals of evapotranspiration and its components remained sufficiently high. The high values of global radiation and saturation deficit in the air favourably influenced the water regime of the analysed forest stand in the dry period.

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The Effectiveness of Evapotranspiration Systems in Disposing of Wastewater in Remote Aboriginal Communities in Northwest Australia

Water Science & Technology ◽

10.2166/wst.1991.0638 ◽

1991 ◽

Vol 23 (10-12) ◽

pp. 1825-1833

Author(s):

D. R. McGrath ◽

G. E. Ho ◽

K. Mathew

Keyword(s):

Water Balance ◽

Water Loss ◽

Balance Equation ◽

Eucalyptus Camaldulensis ◽

Bare Soil ◽

Pan Evaporation ◽

Aboriginal Communities ◽

Water Balance Equation ◽

Northwest Australia

The potential usage of Evapotranspiration (ET) systems in remote Aboriginal communities was investigated. ET system sizing requirements were determined from the water balance equation. Water loss from lysimeters planted with trees (Eucalyptus camaldulensis) or lawn grass and from bare soil and gravel was monitored over several months and compared to pan evaporation measured during the same period. It was found that ET from bare soil and grass followed similar trends to pan evaporation, ranging from 30-60% of pan evaporation for soil and from 60-80% of pan evaporation for grass. ET rates increased in the tanks planted with trees as the plants grew and exceeded pan evaporation rates. Evaporation from gravel-filled lysimeters was low, being as little as 10% of pan evaporation.

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CONTROL OF CUTWORMS IN ASPARAGUS FIELDS IN THE INTERIOR OF BRITISH COLUMBIA

Canadian Journal of Plant Science ◽

10.4141/cjps57-013 ◽

1957 ◽

Vol 37 (2) ◽

pp. 108-112

Author(s):

F. L. Banham ◽

R. H. Handford

Keyword(s):

British Columbia ◽

Soil Surface ◽

Moist Soil ◽

Highly Effective ◽

Euxoa Ochrogaster ◽

Dry Soil

Emulsions of dieldrin, aldrin, isodrin, toxaphene and chlordane applied to the soil surface and incorporated to a depth of about 4 inches proved highly effective in controlling the red-back cutworm, Euxoa ochrogaster (Guen.) when tested in asparagus fields in the interior of British Columbia in the summer of 1953 and 1954. In 1953 aldrin emulsion mixed with the soil was much more effective than when it was left on the soil surface, Bran bait containing paris green, although giving fairly satisfactory control, was less effective and slower in action than the emulsions. In 1952, dieldrin, aldrin, and isodrin dusts, applied to the soil surface, were superior to and faster in action than bran baits containing aldrin or endrin; all of the 1952 treatments were apparently slower in action in dry soil than in relatively moist soil. A survey of asparagus fields treated by growers in 1953 but not in 1954 indicated that aldrin emulsion, mixed with the soil at about 4 lb. of toxicant per acre, protects asparagus for at least two years.

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Contribution of potential evaporation forecasts to 10-day streamflow forecast skill for the Rhine River

Hydrology and Earth System Sciences ◽

10.5194/hess-23-1453-2019 ◽

2019 ◽

Vol 23 (3) ◽

pp. 1453-1467 ◽

Cited By ~ 6

Author(s):

Bart van Osnabrugge ◽

Remko Uijlenhoet ◽

Albrecht Weerts

Keyword(s):

Radiative Forcing ◽

Potential Evapotranspiration ◽

Global Radiation ◽

Forecast Skill ◽

Meteorological Variables ◽

Potential Evaporation ◽

Streamflow Forecasting ◽

Time Step ◽

Streamflow Forecast ◽

Rhine Basin

Abstract. Medium-term hydrologic forecast uncertainty is strongly dependent on the forecast quality of meteorological variables. Of these variables, the influence of precipitation has been studied most widely, while temperature, radiative forcing and their derived product potential evapotranspiration (PET) have received little attention from the perspective of hydrological forecasting. This study aims to fill this gap by assessing the usability of potential evaporation forecasts for 10-day-ahead streamflow forecasting in the Rhine basin, Europe. In addition, the forecasts of the meteorological variables are compared with observations. Streamflow reforecasts were performed with the daily wflow_hbv model used in previous studies of the Rhine using the ECMWF 20-year meteorological reforecast dataset. Meteorological forecasts were compared with observed rainfall, temperature, global radiation and potential evaporation for 148 subbasins. Secondly, the effect of using PET climatology versus using observation-based estimates of PET was assessed for hydrological state and for streamflow forecast skill. We find that (1) there is considerable skill in the ECMWF reforecasts to predict PET for all seasons, and (2) using dynamical PET forcing based on observed temperature and satellite global radiation estimates results in lower evaporation and wetter initial states, but (3) the effect on forecasted 10-day streamflow is limited. Implications of this finding are that it is reasonable to use meteorological forecasts to forecast potential evaporation and use this is in medium-range streamflow forecasts. However, it can be concluded that an approach using PET climatology is also sufficient, most probably not only for the application shown here, but also for most models similar to the HBV concept and for moderate climate zones. As a by-product, this research resulted in gridded datasets for temperature, radiation and potential evaporation based on the Makkink equation for the Rhine basin. The datasets have a spatial resolution of 1.2×1.2 km and an hourly time step for the period from July 1996 through 2015. This dataset complements an earlier precipitation dataset for the same area, period and resolution.

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