SOME FACTORS ASSOCIATED WITH INJURY TO ALFALFA DURING THE 1977–78 WINTER AT BEAVERLODGE, ALBERTA

1980 ◽  
Vol 60 (1) ◽  
pp. 103-112 ◽  
Author(s):  
J. S. McKENZIE ◽  
G. E. McLEAN
Keyword(s):  
Cold Hardiness ◽  
Laboratory Experiments ◽  
Severely Injured ◽  
Factors Associated ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Cutting Management ◽  
Food Reserves ◽  
Perennial Legumes ◽  
Northern Alberta

During the 1977–78 winter, many perennial legumes were severely injured in northern Alberta and British Columbia. The winter was characterized by an early killing frost on 1 Sept. 1977. Air temperatures were −28 °C in late November and −43 °C in early December prior to any appreciable ground snow cover. This caused soil temperatures at 5 cm to drop to −19 °C. Field and laboratory experiments are described in which cold hardiness measurements (LT40), etiolated regrowth weight measurements of root food reserves and visual percent stand estimates were determined on various cultivars of Medicago sativa, M. media and M. falcata prior to, during and/or following the 1977–78 winter. Injury was first observed in plants collected from the field following the low soil temperatures in November and December. Fall cutting management studies indicated that alfalfa harvested during August or early September in 1977 suffered the most severe injury the following spring. In June 1978, first-cut yields of these plots were up to 50% lower than the yields from single-cut control plots or plots harvested after mid-September. M. sativa, M. media and M. falcata cultivars left for seed showed little evidence of winter injury. The results suggest that low fall food reserves which resulted from harvesting during August or early September and low soil temperatures in December and January were two primary factors associated with winter injury. M. sativa stands cut twice in 1977 were more severely injured than stands of M. media or M. falcata. Three-year-old stands of M. media were more severely injured than 2-yr-old stands.

A FIELD TEST FOR ASSESSING THE WINTER HARDINESS OF ALFALFA IN NORTHWESTERN CANADA

1984 ◽  
Vol 64 (4) ◽  
pp. 917-924 ◽  
Author(s):  
J. S. McKENZIE ◽  
G. E. McLEAN
Keyword(s):  
Field Test ◽  
Winter Hardiness ◽  
Early Winter ◽  
Snow Removal ◽  
Air Temperatures ◽  
Two Factors ◽  
Soil Temperatures ◽  
Natural Snow ◽  
Food Reserves ◽  
Northern Alberta

A procedure is described for separating differences in winter hardiness among alfalfa (Medicago sativa L.) cultivars under field conditions. The procedure depends upon two factors associated with winterkill in northern Alberta during the 1977–1978 winter, namely, low food reserves in the crowns resulting from improper cutting management plus cold stress due to lack of snow in early winter. To induce these conditions we recommend that year-old plants be clipped in mid-June, late July and early September and that snow be removed once from the plot during early winter on the first day that air temperatures below −30 °C are forecasted. Natural snow fall can protect the plot for the remainder of the winter. If soil temperatures do not drop close to the range of the LT50 of the control cultivars, snow cover may be removed again provided air temperatures are below −30 °C. Cultivar rankings for winter hardiness following severe stress induced by snow removal were significantly correlated (r = 0.944**) with the mean survival observed at five locations following natural winter stresses in this region. Although additional work is warranted, the induced stress procedure has real merit in screening winter-hardy genotypes in the field and in assessing management techniques to reduce the effects of stressful winter environments on alfalfa production in northwestern Canada.Key words: Alfalfa, winter hardiness, field test, snow removal, frequent clipping

CHANGES IN SURVIVAL OF WINTER CEREALS DUE TO ICE COVER AND OTHER SIMULATED WINTER CONDITIONS

1977 ◽  
Vol 57 (4) ◽  
pp. 1141-1149 ◽  
Author(s):  
C. J. ANDREWS ◽  
M. K. POMEROY
Keyword(s):  
Cold Hardiness ◽  
Triticum Aestivum L ◽  
Ice Cover ◽  
Winter Cereal ◽  
High Soil Moisture ◽  
Winter Cereals ◽  
Air Temperatures ◽  
Average Survival ◽  
Soil Temperatures ◽  
Protected Plants

The survival of winter cereal cultivars of contrasting cold hardiness was determined after various modifications of the winter environment at two locations in 3 yr at Ottawa, Ontario. Artificially produced ice covers reduced survival in all cases, and the severest damage was associated with high soil moisture at the time of ice formation. Maintenance of soil temperatures close to zero by replacement of an insulating snow cover over ice increased average survival by about 10% compared with non-insulated plots. Naturally formed ice covers were less damaging than those artificially produced, and in one case formation of an ice cover protected plants from very low air temperatures, resulting in greater survival than in control plots. Total removal of snow in January was severely damaging, while accumulation of snow at a snowfence allowed increased survival of all cultivars. The correlation between cold hardiness and survival in ice treatments was significant, but one wheat (Triticum aestivum L.) cultivar showed better survival than comparable wheats in a number of ice-stressed treatments, while not showing superiority in unstressed or controlled environment conditions.

scholarly journals Impact of Shade and Fogging on High Tunnel Production and Mineral Content of Organically Grown Lettuce, Basil, and Arugula in Georgia

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 625
Author(s):  
Savanah Laur ◽  
Andre Luiz Biscaia Ribeiro da Silva ◽  
Juan Carlos Díaz-Pérez ◽  
Timothy Coolong
Keyword(s):  
Mineral Content ◽  
Planting Date ◽  
High Tunnel ◽  
Lactuca Sativa L ◽  
Air Temperatures ◽  
Shade Cloth ◽  
High Tunnels ◽  
Soil Temperatures ◽  
Organically Grown ◽  
The Impact

This study evaluated the impact of shade cloth and fogging systems on the microclimate at the plant canopy level and yield of basil (Oscimum basilicum L.), arugula (Eruca vesicaria subsp. Sativa L.), and lettuce (Lactuca sativa L.) planted in mid-September and early October in high tunnels. Fogging systems were installed at canopy level in plots within shaded (30%) and non-shaded high tunnels. Average air temperatures in the shaded high tunnels were 0.9 °C lower than non-shaded high tunnels during the day. Shade cloth significantly reduced soil temperatures during the day and night periods by 1.5 °C and 1.3 °C, respectively, compared to non-shaded treatments. Fogging systems did not have an impact on air temperature, soil temperature, or relative humidity, but did increase canopy leaf wetness. Shade and fogging did not impact the yield of any of the crops grown. Yield was impacted by planting date, with earlier planting result in higher yields of lettuce and basil. Yields for arugula were greater during the second planting date than the first. Planting date and shade cloth interacted to affect the concentrations of macronutrients.

Flower cold hardiness: a potential determinant of the flowering sequence exhibited by bog ericads

1979 ◽  
Vol 57 (9) ◽  
pp. 997-999 ◽  
Author(s):  
R. J. Reader
Keyword(s):  
Low Temperatures ◽  
Cold Hardiness ◽  
Vaccinium Macrocarpon ◽  
Southern Ontario ◽  
Air Temperatures ◽  
Insect Pollinators ◽  
Cold Hardy ◽  
Vaccinium Myrtilloides ◽  
Potential Determinant ◽  
Ledum Groenlandicum

In laboratory freezing trials, cold hardiness of six types of bog ericad flowers differed significantly (i.e., Chamaedaphne calyculata > Andromeda glaucophylla > Kalmia polifolia > Vaccinium myrtilloides > Ledum groenlandicum > Vaccinium macrocarpon) at air temperatures between −4 and −10 °C but not at temperatures above −2 °C. At the Luther Marsh bog in southern Ontario, low temperatures (−3 to −7 °C) would select against May flowering by the least cold hardy ericads. Availability of pollinators, on the other hand, would encourage May flowering by the most cold hardy species. Presumably, competition for insect pollinators has promoted the diversification of bog ericad flowering peaks, while air temperature, in conjunction with flower cold hardiness, determined the order in which flowering peaks were reached.

scholarly journals Quality control of 10-min soil temperatures data at RMI

2015 ◽  
Vol 12 (1) ◽  
pp. 23-30 ◽  
Author(s):  
C. Bertrand ◽  
L. González Sotelino ◽  
M. Journée
Keyword(s):  
Quality Control ◽  
Soil Temperature ◽  
Bare Soil ◽  
Climate Conditions ◽  
Air Temperatures ◽  
Temperature Observation ◽  
Soil Temperatures ◽  
Different Depths ◽  
Temperature Records ◽  
Energy Processes

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.

scholarly journals Seasonal dynamics of methane emissions from a subarctic fen in the Hudson Bay Lowlands

2013 ◽  
Vol 10 (7) ◽  
pp. 4465-4479 ◽  
Author(s):  
K. L. Hanis ◽  
M. Tenuta ◽  
B. D. Amiro ◽  
T. N. Papakyriakou
Keyword(s):  
Soil Temperature ◽  
Air Temperature ◽  
Growing Season ◽  
Near Surface ◽  
Growing Seasons ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Surface Soil Temperature ◽  
Filling Method ◽  
Highly Correlated

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.

scholarly journals Some like it hot: A differential response to changing temperatures by the malaria vectors Anopheles funestus and An. gambiae s.l.

2016 ◽  
Author(s):  
Jacques D Charlwood
Keyword(s):  
Air Temperature ◽  
Light Trap ◽  
Anopheles Funestus ◽  
Malaria Vectors ◽  
Effect Of Temperature ◽  
Night Time ◽  
Environmental Correlations ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Gravid Females

Background: With the possible implications of global warming, the effect of temperature on the dynamics of malaria vectors in Africa has become a subject of increasing interest. Information from the field is, however, relatively sparse. We describe the effect of ambient temperature over a five-year period on the dynamics of An. funestus and An. gambiae s.l., collected from a single village in southern Mozambique where temperatures varied from a night-time minimum of 6oC in the cool season to a daytime maximum of 35oC in the hot season. Results: Mean daily air temperatures varied from 34o C to 20oC and soil temperatures varied from 26 o C to 12 o C. Diurnal variation was greatest in the cooler months of the year and were greater in air temperatures than soil temperatures. During the study 301, 705 female An. funestus were collected in 6043 light-trap collections, 161, 466 in 7397 exit collections and 16, 995 in 1315 resting collections. The equivalent numbers for An. gambiae s.l. are 72, 475 in light-traps, 33, 868 in exit collections and 5, 333 from indoor resting collections. Numbers of mosquito were greatest in the warmer months. Numbers of An. gambiae s.l. went through a one hundredfold change (from a mean of 0.14 mosquitoes a night to 14) whereas numbers of An. funestus merely doubled (from a mean of 20 to 40 a night). The highest environmental correlations and mosquito numbers were between mean air temperature (r2 = 0.52 for An. funestus and 0.77 for An. gambiae s.l.). Numbers of mosquito collected were not related to rainfall with lags of up to four weeks. Numbers of both gravid and unfed An. gambiae complex females in exit collections continued to increase at all temperatures recorded but gravid females of An. funestus decreased at temperatures above 28oC. Overall the numbers of gravid and unfed An. funestus collected in exit collections were not correlated (p = 0.07). For an unknown reason the number of An. gambiae s.l. fell below monitoring thresholds during the study. Conclusions: Mean air temperature was the most important environmental parameter affecting both vectors in this part of Mozambique. Numbers of An. gambiae s.l. increased at all temperatures recorded whilst An. funestus appeared to be adversely affected by temperatures of 28oC and above. These differences may influence the distribution of the vectors as the planet warms.

Soil and air temperatures during prescribed cerated fires in Central Brazil

1993 ◽  
Vol 9 (3) ◽  
pp. 313-320 ◽  
Author(s):  
Antonio Carlos Miranda ◽  
Heloisa Sinátora Miranda ◽  
Inês de Fátima Oliveira Dias ◽  
Braulio Ferreira de Souza Dias
Keyword(s):  
Air Temperature ◽  
Sensu Stricto ◽  
Temperature Measurements ◽  
Fuel Load ◽  
Native Vegetation ◽  
Central Brazil ◽  
Type K ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Recorded Data

ABSTRACTAir and soil temperatures were measured during dry season heading fires in three different physiognomic forms of native vegetation common in Central Brazil: cerrado sensu stricto (dense scrub of shrubs and trees), campo cerrado (open scrub), and campo sujo (open grassland with scattered shrubs). The vegetation was protected from fire for 15 y in some areas, had been burned once every two years, and once each year in other areas. The temperatures were measured with type-k thermocouples and recorded at intervals of 22.5 sees. Air temperature measurements were taken at 1, 60 and 160 cm. Maximum air temperatures ranged from 85°C to 840°C, and the duration above 60°C varied from 20 to 270 seconds. In the soil, negligible temperature increases were recorded below 5 cm depth, whereas at 2 cm maximum soil temperatures varied from 29 to 38°C. Possible influences of fuel load and moisture on the recorded data and on the behaviour of fire in the cerrado ecosystems are discussed.

scholarly journals Frazil-ice entrainment of sediment: large-tank laboratory experiments

2001 ◽  
Vol 47 (158) ◽  
pp. 461-471 ◽  
Author(s):  
Lars Henrik Smedsrud
Keyword(s):  
Laboratory Experiments ◽  
Surface Current ◽  
High Heat ◽  
Heat Fluxes ◽  
Vertical Diffusion ◽  
Turbulent Dissipation ◽  
Frazil Ice ◽  
Air Temperatures ◽  
Sediment Entrainment ◽  
Ice Production

AbstractLaboratory experiments that simulate natural ice-formation processes and sediment entrainment in shallow water are presented. A 10–30 cm s−1 current was forced with impellers in a 20 m long, 1 m deep indoor tank. Turbulence in the flow maintained a suspension of sediments at concentrations of 10–20 mg L−1 at 0.5 m depth. Low air temperatures (∼−15°C) and 5 m s−1 winds resulted in total upward heat fluxes in the range 140–260 W m−2. The cooling produced frazil-ice crystals up to 2 cm in diameter with concentrations up to 4.5 g L−1 at 0.5 m depth. Considerable temporal variability with time-scales of <1 min was documented. A close to constant portion of the smaller frazil crystals remained in suspension. After some hours the larger crystals, which made up most of the ice volume, accumulated as slush at the surface. Current measurements were used to calculate the turbulent dissipation rate, and estimates of vertical diffusion were derived. After 5–8 hours, sediment concentrations in the surface slush were normally close to those of the water. After 24 hours, however, they were 2–4 times higher. Data indicate that sediment entrainment depends on high heat fluxes and correspondingly high frazil-ice production rates, as well as sufficiently strong turbulence. Waves do not seem to increase sediment entrainment significantly.

A Study of the Annual Soil Temperature Wave

1952 ◽  
Vol 5 (2) ◽  
pp. 303 ◽  
Author(s):  
ES West
Keyword(s):  
Soil Temperature ◽  
Air Temperature ◽  
Temperature Wave ◽  
Theoretical Equation ◽  
Mean Temperature ◽  
Air Temperatures ◽  
Soil Temperatures

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.

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