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TDR Technique for Estimating the Intensity of Evapotranspiration of Turfgrasses.

Janik G, Wolski K, Daniel A, Albert M, Skierucha W, Wilczek A, Szyszkowski P, Walczak A - ScientificWorldJournal (2015)

Bottom Line: Those parameters are the temperature and the volumetric moisture of soil at the depth of 2.5 cm.Evapotranspiration has the character of a modified logistic function with empirical parameters.It assumes the form ETR(θ (2.5 cm), T (2.5 cm)) = A/(1 + B · e (-C · (θ (2.5 cm) · T (2.5 cm)), where: ETR(θ (2.5 cm), T (2.5 cm)) is evapotranspiration [mm · h(-1)], θ (2.5 cm) is volumetric moisture of soil at the depth of 2.5 cm [m(3) · m(-3)], T (2.5 cm) is soil temperature at the depth of 2.5 cm [°C], and A, B, and C are empirical coefficients calculated individually for each of the grass species [mm · h(1)], and [-], [(m(3) · m(-3) · °C)(-1)].

View Article: PubMed Central - PubMed

Affiliation: Institute of Environmental Protection and Development, Wrocław University of Environmental and Life Sciences, Plac Grunwaldzki 24, 50-363 Wrocław, Poland.

ABSTRACT
The paper presents a method for precise estimation of evapotranspiration of selected turfgrass species. The evapotranspiration functions, whose domains are only two relatively easy to measure parameters, were developed separately for each of the grass species. Those parameters are the temperature and the volumetric moisture of soil at the depth of 2.5 cm. Evapotranspiration has the character of a modified logistic function with empirical parameters. It assumes the form ETR(θ (2.5 cm), T (2.5 cm)) = A/(1 + B · e (-C · (θ (2.5 cm) · T (2.5 cm)), where: ETR(θ (2.5 cm), T (2.5 cm)) is evapotranspiration [mm · h(-1)], θ (2.5 cm) is volumetric moisture of soil at the depth of 2.5 cm [m(3) · m(-3)], T (2.5 cm) is soil temperature at the depth of 2.5 cm [°C], and A, B, and C are empirical coefficients calculated individually for each of the grass species [mm · h(1)], and [-], [(m(3) · m(-3) · °C)(-1)]. The values of evapotranspiration calculated on the basis of the presented function can be used as input data for the design of systems for the automatic control of irrigation systems ensuring optimum moisture conditions in the active layer of lawn swards.

No MeSH data available.


Related in: MedlinePlus

Diurnal dynamics of evapotranspiration and temperature for the four grasses on 13.06.2013 calculated with time step of Δt = 1 h; ETR is evapotranspiration and T is soil temperature at the depth of 2.5 cm.
© Copyright Policy - open-access
Related In: Results  -  Collection


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fig5: Diurnal dynamics of evapotranspiration and temperature for the four grasses on 13.06.2013 calculated with time step of Δt = 1 h; ETR is evapotranspiration and T is soil temperature at the depth of 2.5 cm.

Mentions: Figure 5 presents an example of the runs of evapotranspiration for each of the grasses during the period of one day, on the 13th of June (3rd day). These data were selected for graphic illustration as on that day there was a drop in insolation. Thanks to this, it was possible to observe a rapid change of evapotranspiration, which demonstrates the high sensitivity of the proposed method of measurement. The calculations were made with the time step of Δt = 1 h using, as before, relation (4). During the hours from 0:00 to 5:00 and from 19:00 to 24:00, the values of ETR for each grass are zeroed. The occasional small negative values might have been caused by a lack of stability of the method for short time steps or an influx of water to the monoliths as a result of water infiltration from the atmosphere which occurs also during the nonrainfall periods [28]. During the day-time period, the variation of the values of ETR is as follows: in the morning, from 5:00 there is a systematic increase to the maximum value which is attained at 9:00 for Niweta, amounting to 0.77 mm·h−1, at 11:00 for Sawa, amounting to 0.45 mm·h−1, at 10:00 for Nira, amounting to 0.62 mm·h−1, and at 10:00 for the grass mix SPORT—0.82 mm·h−1. Then, for each of the grasses, a decrease of evapotranspiration takes place, until 13:00 for Sawa and till 14:00 for the remaining grasses. The minimum value of evapotranspiration during that period varies from 0.05 mm·h−1 for Niweta to 0.22 mm·h−1 for the remaining grasses. After that, in the afternoon hours slight increases take place in the values of ETR, up to values that amount to from 0.47 mm·h−1 for Sawa to 0.72 mm·h−1 for Niweta. The afternoon maxima are attained at 15:00, in spite of a slight drop in soil temperature at the depth of 2.5 cm at the time. This results from the fact that the maximum temperature on soil surface (h = 0) appears earlier than the maximum values at 16:00, for example, at 15:00. (The effect of differentiation of ETR values for the various grasses is related to the variation of moisture in the surface horizon of soil.) At 18:00 for Niweta and at 19:00 for the remaining grasses evapotranspiration ceases. The decrease of evapotranspiration in the afternoon hours is due to the fact that each day at that time the soil samples were in the shade. The shading, resulting from sample positioning, occurred from about 10:00 to approximately 13:00. It was also the cause of the disturbance in the course of the dynamics of temperature in the surface layers (Figure 5). Comparing the runs of evapotranspiration and temperature for the four grasses, we note that the maximum of evapotranspiration before noon takes place at 9:00 for Niweta, at 10:00 for Nira and the turfgrass mix, and at 11:00 for Sawa. Meanwhile, the maximum of temperature for each of the grasses occurs at 13:00. Moreover, the afternoon maximum of evapotranspiration for each grass occurs at 15:00 and of temperature at 16:00, except for Nira for which that maximum occurs at 17:00. This means that changes in evapotranspiration precede changes of temperature at the depth of 2.5 cm. That fact should be attributed to temperature changes at the depth of 2.5 cm being delayed in relation to soil temperature changes on its surface. Further on in the study, the effect of moisture and, at the same time, of the temperature of the surface layer of soil on the value of evapotranspiration was analysed.


TDR Technique for Estimating the Intensity of Evapotranspiration of Turfgrasses.

Janik G, Wolski K, Daniel A, Albert M, Skierucha W, Wilczek A, Szyszkowski P, Walczak A - ScientificWorldJournal (2015)

Diurnal dynamics of evapotranspiration and temperature for the four grasses on 13.06.2013 calculated with time step of Δt = 1 h; ETR is evapotranspiration and T is soil temperature at the depth of 2.5 cm.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4581558&req=5

fig5: Diurnal dynamics of evapotranspiration and temperature for the four grasses on 13.06.2013 calculated with time step of Δt = 1 h; ETR is evapotranspiration and T is soil temperature at the depth of 2.5 cm.
Mentions: Figure 5 presents an example of the runs of evapotranspiration for each of the grasses during the period of one day, on the 13th of June (3rd day). These data were selected for graphic illustration as on that day there was a drop in insolation. Thanks to this, it was possible to observe a rapid change of evapotranspiration, which demonstrates the high sensitivity of the proposed method of measurement. The calculations were made with the time step of Δt = 1 h using, as before, relation (4). During the hours from 0:00 to 5:00 and from 19:00 to 24:00, the values of ETR for each grass are zeroed. The occasional small negative values might have been caused by a lack of stability of the method for short time steps or an influx of water to the monoliths as a result of water infiltration from the atmosphere which occurs also during the nonrainfall periods [28]. During the day-time period, the variation of the values of ETR is as follows: in the morning, from 5:00 there is a systematic increase to the maximum value which is attained at 9:00 for Niweta, amounting to 0.77 mm·h−1, at 11:00 for Sawa, amounting to 0.45 mm·h−1, at 10:00 for Nira, amounting to 0.62 mm·h−1, and at 10:00 for the grass mix SPORT—0.82 mm·h−1. Then, for each of the grasses, a decrease of evapotranspiration takes place, until 13:00 for Sawa and till 14:00 for the remaining grasses. The minimum value of evapotranspiration during that period varies from 0.05 mm·h−1 for Niweta to 0.22 mm·h−1 for the remaining grasses. After that, in the afternoon hours slight increases take place in the values of ETR, up to values that amount to from 0.47 mm·h−1 for Sawa to 0.72 mm·h−1 for Niweta. The afternoon maxima are attained at 15:00, in spite of a slight drop in soil temperature at the depth of 2.5 cm at the time. This results from the fact that the maximum temperature on soil surface (h = 0) appears earlier than the maximum values at 16:00, for example, at 15:00. (The effect of differentiation of ETR values for the various grasses is related to the variation of moisture in the surface horizon of soil.) At 18:00 for Niweta and at 19:00 for the remaining grasses evapotranspiration ceases. The decrease of evapotranspiration in the afternoon hours is due to the fact that each day at that time the soil samples were in the shade. The shading, resulting from sample positioning, occurred from about 10:00 to approximately 13:00. It was also the cause of the disturbance in the course of the dynamics of temperature in the surface layers (Figure 5). Comparing the runs of evapotranspiration and temperature for the four grasses, we note that the maximum of evapotranspiration before noon takes place at 9:00 for Niweta, at 10:00 for Nira and the turfgrass mix, and at 11:00 for Sawa. Meanwhile, the maximum of temperature for each of the grasses occurs at 13:00. Moreover, the afternoon maximum of evapotranspiration for each grass occurs at 15:00 and of temperature at 16:00, except for Nira for which that maximum occurs at 17:00. This means that changes in evapotranspiration precede changes of temperature at the depth of 2.5 cm. That fact should be attributed to temperature changes at the depth of 2.5 cm being delayed in relation to soil temperature changes on its surface. Further on in the study, the effect of moisture and, at the same time, of the temperature of the surface layer of soil on the value of evapotranspiration was analysed.

Bottom Line: Those parameters are the temperature and the volumetric moisture of soil at the depth of 2.5 cm.Evapotranspiration has the character of a modified logistic function with empirical parameters.It assumes the form ETR(θ (2.5 cm), T (2.5 cm)) = A/(1 + B · e (-C · (θ (2.5 cm) · T (2.5 cm)), where: ETR(θ (2.5 cm), T (2.5 cm)) is evapotranspiration [mm · h(-1)], θ (2.5 cm) is volumetric moisture of soil at the depth of 2.5 cm [m(3) · m(-3)], T (2.5 cm) is soil temperature at the depth of 2.5 cm [°C], and A, B, and C are empirical coefficients calculated individually for each of the grass species [mm · h(1)], and [-], [(m(3) · m(-3) · °C)(-1)].

View Article: PubMed Central - PubMed

Affiliation: Institute of Environmental Protection and Development, Wrocław University of Environmental and Life Sciences, Plac Grunwaldzki 24, 50-363 Wrocław, Poland.

ABSTRACT
The paper presents a method for precise estimation of evapotranspiration of selected turfgrass species. The evapotranspiration functions, whose domains are only two relatively easy to measure parameters, were developed separately for each of the grass species. Those parameters are the temperature and the volumetric moisture of soil at the depth of 2.5 cm. Evapotranspiration has the character of a modified logistic function with empirical parameters. It assumes the form ETR(θ (2.5 cm), T (2.5 cm)) = A/(1 + B · e (-C · (θ (2.5 cm) · T (2.5 cm)), where: ETR(θ (2.5 cm), T (2.5 cm)) is evapotranspiration [mm · h(-1)], θ (2.5 cm) is volumetric moisture of soil at the depth of 2.5 cm [m(3) · m(-3)], T (2.5 cm) is soil temperature at the depth of 2.5 cm [°C], and A, B, and C are empirical coefficients calculated individually for each of the grass species [mm · h(1)], and [-], [(m(3) · m(-3) · °C)(-1)]. The values of evapotranspiration calculated on the basis of the presented function can be used as input data for the design of systems for the automatic control of irrigation systems ensuring optimum moisture conditions in the active layer of lawn swards.

No MeSH data available.


Related in: MedlinePlus