Effects of soil temperature and phosphorus supply on growth and composition of Lupinus angustifolius L. and L. cosentinii Guss

1974 ◽  
Vol 25 (6) ◽  
pp. 885 ◽  
Author(s):  
MS Rahman ◽  
JS Gladstones ◽  
N Thurling
Keyword(s):  
Phosphorus Uptake ◽  
Bath Temperature ◽  
Lateritic Soil ◽  
Root Temperature ◽  
Positive Interaction ◽  
Air Temperatures ◽  
Two Factors ◽  
Nitrogen Concentrations ◽  
Soil Temperatures ◽  
Nutrient Solutions

Two Lupinus species, L. angustifolius L. and L. cosentinii Guss., were grown in pots in the glasshouse on a virgin lateritic soil, with two soil temperatures attained by immersion in water-baths at 10 and 20°C, and four rates of superphosphate ranging from 0 to 1792 kg ha-l. Air temperatures were not controlled. Dry matter, and phosphorus and nitrogen concentrations, were measured separately for tops and roots after harvest at 7 weeks. In a second experiment, the rate of early radicle elongation was measured for the two species in complete nutrient solutions at 10 and 20°.Water-bath temperature markedly influenced the growth of both roots and tops, growth with 20° being approximately double that with 10° in both species. At both bath temperatures, responses to superphosphate closely paralleled those observed previously on the same soil in the field. There was a slight positive interaction between bath temperature and superphosphate rate, but in the main the effects of the two factors were independent and additive. The results did not support the suggestion that reduced growth with low root temperature may be due primarily to reduced phosphorus uptake. Nor did they indicate reductions in nodulation, nitrogen fixation, or translocation of either nitrogen or phosphorus from roots to tops as likely causes. It is suggested that temperature may have directly affected the growth and/or metabolism of the roots, influencing their production of growth substances, which in turn influenced processes controlling top growth.

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

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.

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.

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.

Do wheat breeders have suitable genetic variation to overcome short coleoptiles and poor establishment in the warmer soils of future climates?

2016 ◽  
Vol 43 (10) ◽  
pp. 961 ◽  
Author(s):  
Greg J. Rebetzke ◽  
Bangyou Zheng ◽  
Scott C. Chapman
Keyword(s):  
Soil Temperature ◽  
Crop Yields ◽  
Triticum Aestivum L ◽  
Wheat Breeding ◽  
Crop Failure ◽  
Coleoptile Length ◽  
Crop Establishment ◽  
Air Temperatures ◽  
Reduced Height ◽  
Soil Temperatures

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.

PREDICTION OF SOIL TEMPERATURE FROM AIR TEMPERATURE FOR ESTIMATING CORN EMERGENCE

1990 ◽  
Vol 70 (3) ◽  
pp. 619-628 ◽  
Author(s):  
L. M. DWYER ◽  
H. N. HAYHOE ◽  
J. L. B. CULLEY
Keyword(s):  
Nonlinear Response ◽  
Zea Mays L ◽  
Thermal Environment ◽  
Growing Degree Days ◽  
Degree Days ◽  
Emergence Period ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Production Areas ◽  
Zone Temperature

The soil thermal environment is critical to corn (Zea mays L.) emergence in short-season production areas. A field study was therefore carried out during the emergence period to test a method to predict 0.05-m soil temperatures from air temperatures and to develop a method to quantify emergence rates as a function of actual and predicted soil thermal units. Thermal units (base 10 °C) were calculated from hourly air and measured and predicted 0.05-m soil temperatures; these thermal units were fit to test emergence data collected on six cultivars. The nonlinear response of percentage emergence to thermal units was approximated by an exponential function. Comparisons of cultivar emergence rates, expressed as the number of thermal units to 0 and 75% emergence, statistically differentiated (P ≤ 0.05) the test cultivars into three main groupings. When predicted soil temperatures were used to calculate the number of thermal units, the thermal units to specific emergence levels were within the equivalent of 1 or 2 d of those generated using measured soil temperatures.Key words: Growing degree days, regression, thermal regimes, seed zone temperature, corn emergence

Experimental Investigation of a Lab-Scale, Cross-Flow Grain Dryer for Testing of Drying Efficiency and Characteristic Profiles of a Packed Bed

2015 ◽  
Author(s):  
Taylor N. Suess ◽  
Michael P. Twedt ◽  
Stephen P. Gent
Keyword(s):  
Energy Use ◽  
Cross Flow ◽  
Electric Heating ◽  
Packed Bed ◽  
Operating Conditions ◽  
Heating Process ◽  
Air Temperatures ◽  
Two Factors ◽  
Forced Air ◽  
Drying Efficiency

This study investigates the drying mechanisms of corn when it is exposed to air at elevated temperature and velocity within a cross-flow packed bed dryer. A highly-instrumented laboratory-scale experimental test dryer was constructed to batch-dry samples of 0.03 m3 (1 ft3) of high moisture corn. This is achieved using a perforated wall drying chamber with forced air at temperatures ranging from 180–240°F. The high temperature, high velocity air entering the column is supplied by a variable speed fan and a variable Wattage electric heating coil through a 0.09 m2 (1 ft2) square air duct. This device is able to precisely control the drying air temperate and flow rate, while also measuring the temperature and humidity of the air exiting the dryer. In creating and instrumenting this apparatus, tests were performed to analyze both energy use and drying rate to determine the operating conditions that find a balance between energy and time requirements for moisture removal. This study used a variety of supply air temperatures and air flow rates in drying samples of corn at two initial moisture contents (19%MC and 24%MC) to 15%MC. This is done to determine if there are notable differences in energy requirements (Btu/pound water removed) between different operating conditions. This study determined that corn undergoes a significant pre-heating process before peak drying efficiency is achieved. Current grain dryer designs should focus the most energy just after that pre-heating process for highest overall efficiencies. Additionally, this study found an inverse relationship between dry time and energy efficiency, which showed that an optimum balance between those two factors should be identified.

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