scholarly journals EFEITOS DO FOGO SOBRE ALGUMAS VARIÁVEIS MICROMETEOROLÓGICAS EM UMA FLORESTA DE BRACATINGA (Mimosa scabrella, Benth.), NO MUNICÍPIO DE COLOMBO, PR

FLORESTA ◽  
2004 ◽  
Vol 34 (2) ◽  
Author(s):  
Leocadio Grodzki ◽  
Ronaldo Viana Soares ◽  
Antonio Carlos Batista ◽  
Paulo Henrique Caramori

O sistema agroflorestal da bracatinga utiliza queima após o corte e retirada da madeira, dando lugar à semeadura de espécies agrícolas. A queima controlada altera a temperatura do ar e do solo. A mudança de refletividade da superfície é mais rápida que dos reflorestamentos próximos. A transformação das folhas e galhos secos em cinza após a queima, faz com que haja mudanças do albedo, alterando o balanço energético. Os resultados mostram temperaturas do ar de 600ºC por 20-40 segundos a 1 cm do solo e de 100 a 300°C a 60 e 160cm do solo, respectivamente, durante 1 minuto. Temperaturas de 100ºC ao nível do solo residiram por mais de 3 minutos. A temperatura do solo não foi afetada a 2,5cm de profundidade. Durante a queima, a temperatura se elevou em 1ºC. O albedo de 0,24 antes da queima, passou para 0,21 logo após a queima. Após 60 dias, o albedo voltou a 0,24 devido a recomposição da vegetação. FIRE EFECTS ON SOME MICROMETEOROLOGICAL VARIABLES IN A BRACATINGA (Mimosa scabrella, Benth.) FOREST, COLOMBO, PR Abstract The bracatinga agriculture-forest systems adopted by farmers consists on burning the residues after wood’s harvesting prior to sowing the crops. This procedure is repeated each 6 to 8 years in the same area. The prescribed burning changes air and soil temperatures. Changes in reflectivity are faster then in the surrounding forest areas. Transforming leaves and branches into ashes after burning changes the albedo of the surface, altering the energetic balance. Results showed air temperatures of 600°C during 20 to 40 seconds, 1cm above the soil surface, and 100 to 300°C at 60 and 160cm above the soil surface, during 1 minute. Temperatures over 100°C on the soil surface were observed for more than 3 minutes. Soil temperature was not affected at 2.5cm depth; during burning, the temperature raised only 1ºC. The surface albedo that was 0,24 before the burning changed to 0,21 after burning and returned to 0.24 sixty days after the burning due to the vegetation regeneration.

2015 ◽  
Vol 12 (1) ◽  
pp. 23-30 ◽  
Author(s):  
C. Bertrand ◽  
L. González Sotelino ◽  
M. Journée

Abstract. Soil temperatures at various depths are unique parameters useful to describe both the surface energy processes and regional environmental and climate conditions. To provide soil temperature observation in different regions across Belgium for agricultural management as well as for climate research, soil temperatures are recorded in 13 of the 20 automated weather stations operated by the Royal Meteorological Institute (RMI) of Belgium. At each station, soil temperature can be measured at up to 5 different depths (from 5 to 100 cm) in addition to the bare soil and grass temperature records. Although many methods have been developed to identify erroneous air temperatures, little attention has been paid to quality control of soil temperature data. This contribution describes the newly developed semi-automatic quality control of 10-min soil temperatures data at RMI.


2013 ◽  
Vol 10 (7) ◽  
pp. 4465-4479 ◽  
Author(s):  
K. L. Hanis ◽  
M. Tenuta ◽  
B. D. Amiro ◽  
T. N. Papakyriakou

Abstract. Ecosystem-scale methane (CH4) flux (FCH4) over a subarctic fen at Churchill, Manitoba, Canada was measured to understand the magnitude of emissions during spring and fall shoulder seasons, and the growing season in relation to physical and biological conditions. FCH4 was measured using eddy covariance with a closed-path analyser in four years (2008–2011). Cumulative measured annual FCH4 (shoulder plus growing seasons) ranged from 3.0 to 9.6 g CH4 m−2 yr−1 among the four study years, with a mean of 6.5 to 7.1 g CH4 m−2 yr−1 depending upon gap-filling method. Soil temperatures to depths of 50 cm and air temperature were highly correlated with FCH4, with near-surface soil temperature at 5 cm most correlated across spring, fall, and the shoulder and growing seasons. The response of FCH4 to soil temperature at the 5 cm depth and air temperature was more than double in spring to that of fall. Emission episodes were generally not observed during spring thaw. Growing season emissions also depended upon soil and air temperatures but the water table also exerted influence, with FCH4 highest when water was 2–13 cm below and lowest when it was at or above the mean peat surface.


1952 ◽  
Vol 5 (2) ◽  
pp. 303 ◽  
Author(s):  
ES West

Soil temperatures recorded at Griffith over an 8 year period at a depth ranging from 1 in. to 8 ft. have been examined and compared with air temperatures. The observed fluctuations m the soil temperatures fit closely the theoretical equation for the propagation of a simple harmonic temperature wave into the so11. The diffusivity of the sol1 has been deduced and compared with values found by other workers in other localities. The annual wave of the daily mean temperature at the surface of the soil has been deduced and compared with the annual wave of the dally mean air temperature and the differences in the means, amplitudes, and phase displacements have been discussed.


2016 ◽  
Vol 43 (10) ◽  
pp. 961 ◽  
Author(s):  
Greg J. Rebetzke ◽  
Bangyou Zheng ◽  
Scott C. Chapman

Increases in air and soil temperatures will impact cereal growth and reduce crop yields. Little is known about how increasing temperatures will impact seedling growth and crop establishment. Climate forecast models predict that by 2060, mean and maximum air temperatures in the Australian wheatbelt will increase by 2−4°C during the March–June sowing period, and particularly at lower latitudes. Concomitant increases in soil temperature will shorten coleoptile length to reduce crop establishment, particularly where deep sowing to access sub-surface moisture. Mean coleoptile length was reduced in commercial wheat (Triticum aestivum L.) germplasm with increasing soil temperature (106 mm and 51 mm at 15°C and 31°C, respectively). Coleoptile lengths of modern semidwarf varieties were significantly (P < 0.01) shorter than those of older tall wheats at 15°C (95 mm and 135 mm) and 31°C (46 mm and 70 mm). A 12-parent diallel indicated large additive and small non-maternal genetic effects for coleoptile length at 15°C and 27°C. Large genotype rank changes for coleoptile length across temperatures (rs = 0.37, P < 0.05) contributed to smaller entry-mean heritabilities (0.41–0.67) to reduce confidence in selection for long-coleoptile genotypes across contrasting temperatures. General combining ability effects were strongly correlated across temperatures (rp = 0.81, P < 0.01), indicating the potential of some donors in identification of progeny with consistently longer coleoptiles. Warmer soils in future will contribute to poor establishment and crop failure, particularly with deep-sown semidwarf wheat. Breeding long-coleoptile genotypes with improved performance will require targeted selection at warmer temperatures in populations incorporating novel sources of reduced height and greater coleoptile length.


1928 ◽  
Vol 18 (1) ◽  
pp. 90-122 ◽  
Author(s):  
E. McKenzie Taylor

1. The soil temperatures in Egypt at a number of depths have been recorded by means of continuous recording thermometers. In general, the records show that the amplitude of the temperature wave at the surface of the soil is considerably greater than the air temperature wave. There is, however, a considerable damping of the wave with depth, no daily variation in temperature being observed at a depth of 100 cm.2. No definite relation between the air and soil temperatures could be traced. The maximum air temperature was recorded in May and the maximum soil temperature in July.3. The amplitude of the temperature wave decreases with increase in depth. The decrease in amplitude of the soil temperature wave is not regular owing to variations in the physical properties of the soil layers. Between any two depths, the ratio of the amplitudes of the temperature waves is constant throughout the year. The amplitude of the soil temperature wave bears no relation to the amplitude of the air temperature wave.4. The time of maximum temperature at the soil surface is constant throughout the year at 1 p.m. The times of maximum temperature at depths below the surface lag behind the time of surface maximum, but they are constant throughout the year. When plotted against depth, the times of maximum at the various soil depths lie on a straight line.


2013 ◽  
Vol 43 (3) ◽  
pp. 209-223 ◽  
Author(s):  
Jana Krčmáŕová ◽  
Hana Stredová ◽  
Radovan Pokorný ◽  
Tomáš Stdŕeda

Abstract The aim of this study was to evaluate the course of soil temperature under the winter wheat canopy and to determine relationships between soil temperature, air temperature and partly soil moisture. In addition, the aim was to describe the dependence by means of regression equations usable for phytopathological prediction models, crop development, and yield models. The measurement of soil temperatures was performed at the experimental field station ˇZabˇcice (Europe, the Czech Republic, South Moravia). The soil in the first experimental plot is Gleyic Fluvisol with 49-58% of the content particles measuring < 0.01 mm, in the second experimental plot, the soil is Haplic Chernozem with 31-32% of the content particles measuring < 0.01 mm. The course of soil temperature and its specifics were determined under winter wheat canopy during the main growth season in the course of three years. Automatic soil temperature sensors were positioned at three depths (0.05, 0.10 and 0.20 m under soil surface), air temperature sensor in 0.05 m above soil surface. Results of the correlation analysis showed that the best interrelationships between these two variables were achieved after a 3-hour delay for the soil temperature at 0.05 m, 5-hour delay for 0.10 m, and 8-hour delay for 0.20 m. After the time correction, the determination coefficient reached values from 0.75 to 0.89 for the depth of 0.05 m, 0.61 to 0.82 for the depth of 0.10 m, and 0.33 to 0.70 for the depth of 0.20 m. When using multiple regression with quadratic spacing (modeling hourly soil temperature based on the hourly near surface air temperature and hourly soil moisture in the 0.10-0.40 m profile), the difference between the measured and the model soil temperatures at 0.05 m was −2.16 to 2.37 ◦ C. The regression equation paired with alternative agrometeorological instruments enables relatively accurate modeling of soil temperatures (R2 = 0.93).


2020 ◽  
Vol 1 (1) ◽  
pp. 12
Author(s):  
Maurício Dominguez Nasser ◽  
Estefânia Martins Bardiviesso ◽  
Ariel Santivañez Aguilar ◽  
Augusto Zonta

Plants can tolerate a wide range of soil temperature variations, but their development is affected when the soil undergoes higher or lower temperatures of certain extreme values. The aim of this study was to assess the soil temperature of two regions of the state of São Paulo, Brazil. Daily measurements of soil temperature were taken at two weather stations, one in the municipality of Adamantina (soil classified as Podzolic, Dark Red Latosol, Eutrophic, moderate A, of sandy/medium texture) and another in the municipality Monte Alegre do Sul (soil classified as Red Yellow Podzolic, of fine sandy-clayey texture) within a period of 365 days. The experimental design was completely randomized, with the two municipalities being the treatments, and 12 repetitions determined by monthly averages. The soil temperature at a 3-cm depth in Adamantina reached values above 40°C, values not observed in Monte Alegre do Sul. At a 12-cm depth, there were no differences between the municipalities. In Monte Alegre do Sul, the recorded soil temperatures proved suitable for crops, with better use of organic matter by the soil and greater stability of surface temperature throughout the day compared to Adamantina. In Adamantina, however, the use of agronomic technology is required to ensure greater stability of surface temperature. The temperature throughout the year in the soil surface layer in the Adamantina region in the afternoon was higher than in the Monte Alegre do Sul region, a fact that implies the need of differentiated agronomic technology depending on the cultivation location.


2018 ◽  
Vol 5 (4) ◽  
pp. 149-154 ◽  
Author(s):  
O M Fediuk ◽  
N O Bilyavska ◽  
E K Zolotareva

In the natural conditions early-spring period development of Galanthus nivalis L., the leaves germination from bulbs was carried out in the soil surface layer, mainly, covered with snow, so the leaves were exposed to low soil temperatures. It was found, that at the leaf germination stage, when exposed to minus soil temperature, the mitochondria were predominantly elongated, that is, functionally active. Under the influence of positive temperature, the mitochondria form changed to a round one, which indicates their transition to low functional activity. A similar tendency was manifested even during the budding stage, in particular, when the soil temperature was lowered to an average of –3.47 °C, the mitochondria changed their form to an elongated one, that is, they passed into an active functional state. Wherein, the temperature of the leaves was higher by 3.84 °C compared to the soil. At the stages of germination and budding of G. nivalis under natural conditions, a direct correlation was found between the soil surface layer temperature and the leaves temperature, and at the flowering stage this relation was reverse. During the flowering stage, despite the influence of predominantly positive soil temperatures, leaves growth was significantly slowed, and their temperature was only slightly higher by 0.38 °C compared to the soil. At the same time, the mitochondria changed their shape to a round one. Thus, the increase in their long axis at different stages in spring development, are aimed at adapting to influence low temperatures of the soil surface layer.


Soil Research ◽  
2011 ◽  
Vol 49 (4) ◽  
pp. 305 ◽  
Author(s):  
Brian Horton ◽  
Ross Corkrey

Soil temperatures are related to air temperature and rainfall on the current day and preceding days, and this can be expressed in a non-linear relationship to provide a weighted value for the effect of air temperature or rainfall based on days lag and soil depth. The weighted minimum and maximum air temperatures and weighted rainfall can then be combined with latitude and a seasonal function to estimate soil temperature at any depth in the range 5–100 cm. The model had a root mean square deviation of 1.21–1.85°C for minimum, average, and maximum soil temperature for all weather stations in Australia (mainland and Tasmania), except for maximum soil temperature at 5 and 10 cm, where the model was less precise (3.39° and 2.52°, respectively). Data for this analysis were obtained from 32–40 Bureau of Meteorology weather stations throughout Australia and the proposed model was validated using 5-fold cross-validation.


MAUSAM ◽  
2021 ◽  
Vol 42 (3) ◽  
pp. 269-274
Author(s):  
B.S. LAMBA ◽  
N.N. KHAMBETE

Harmonic analysis of weekly means of soil temperatures at 5,.15 and 30 cm; depths have been done for seven stations of .India. The corresponding amplitudes and phase angles In respect of different harmonics are presented-    The warmest soil near the soil surface (5 cm depth) occurs during the period 16th to 19th week. While the  highest maximum occurs during the period 20th to 26th week (30 cm depth).  


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