Influence of canopy microclimate on incidence and severity of dogwood anthracnose

1992 ◽  
Vol 70 (5) ◽  
pp. 1093-1096 ◽  
Author(s):  
Dan O. Chellemi ◽  
Kerry O. Britton
Keyword(s):  
Vapor Pressure ◽  
Air Temperature ◽  
Photosynthetically Active Radiation ◽  
Vapor Pressure Deficit ◽  
Disease Incidence ◽  
Cornus Florida ◽  
Active Radiation ◽  
Dogwood Anthracnose ◽  
Low Levels ◽  
Understory Trees

Incidence and severity of dogwood anthracnose within the interior and exterior canopies of exposed dogwood (Cornus florida L.) trees and canopies of understory trees were recorded over a 53-day period during the summer of 1990. Concurrent measurements of vapor pressure deficit, air temperature, evaporative potential, and photosynthetically active radiation within the canopies were also recorded. Disease incidence was significantly lower in the exterior canopy of exposed trees than in other canopy locations. Disease severity was significantly different among all three canopy locations, with the lowest severity in exterior canopies of exposed trees and the greatest severity in canopies of understory trees. Of the climatic variables measured, evaporative potential provided the most consistent contrast among microclimates at the various canopy locations. Mean evaporative potentials averaged over 6- to 10-day intervals ranged from 0.00 g H2O h−1 in understory and exposed, interior canopies to 0.40 g H2O h−1 in exposed, exterior canopies. Disease incidence and severity were greater in canopies associated with low levels of evaporative potential. Key words: Cornus florida L., dogwood anthracnose, canopy microclimate, evaporative potential.

scholarly journals 096 QUANTIFYING THE EFFECT OF SUPPLEMENTAL LIGHTING ON PLANT TEMPERATURES IN GREENHOUSES

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 442a-442
Author(s):  
James E. Faust ◽  
Royal D. Heins
Keyword(s):  
High Pressure ◽  
Vapor Pressure ◽  
Air Temperature ◽  
Catharanthus Roseus ◽  
Vapor Pressure Deficit ◽  
Shoot Tip ◽  
Total Radiation ◽  
Degree Day ◽  
Air Temperatures ◽  
Supplemental Lighting

The effects of supplemental lighting on vinca (Catharanthus roseus L.) plant temperature were quantified in greenhouses maintained at air temperatures of 15. 25, and 35C. High-pressure sodium (HPS) lamps delivering 100 μmol·m-2·s-1 PPF provided 73 W · m-2 of total radiation (400 to 50,000 nm) to lighted plants. Plant shoot-tip temperature was measured by using 40-gauge thermocouples. Relative to air temperature, plant shoot-tip temperature depended on the irradiance and vapor-pressure deficit (VPD). Irrespective of VPD, the additional irradiance absorbed by plants under the HPS lamps increased plant temperature 1 to 2°C. Under relatively low VPD conditions (1 kPa), plant temperature was greater than air temperature, while under high VPD conditions (4 to 5 kPa), temperature of both lighted and unlighted plants remained below air temperature throughout the day. Temperature of lighted plants however, remained 1 to 2°C above that of unlighted plants. Analysis of a degree-day model of vinca development showed hastened development associated with supplemental lighting could be explained by increased plant temperature rather than any specific photosynthetic effect.

scholarly journals Above- and Belowground Microclimate of Grow Tubes in an Organic Mulch-incorporated, Raised Bed System for Blueberry

HortScience ◽  
2013 ◽  
Vol 48 (11) ◽  
pp. 1363-1369
Author(s):  
Julie M. Tarara ◽  
Bernardo Chaves ◽  
Bernadine C. Strik
Keyword(s):  
Vapor Pressure ◽  
Air Temperature ◽  
Vapor Pressure Deficit ◽  
Vaccinium Corymbosum ◽  
Temperature Data ◽  
Radiation Load ◽  
Organic Mulch ◽  
Woody Perennial ◽  
Soil Temperatures ◽  
Raised Bed

Grow tubes are well established in forestry and are gaining attention in establishing some woody perennial crops. To date, microclimate descriptions have addressed the aboveground environment, but a mulched raised bed system with organic mulch-incorporated soil requires both the above- and belowground microclimate to be quantified. We measured the microclimate of commercially used, non-ventilated translucent and non-ventilated opaque grow tubes in a model crop of blueberry (Vaccinium corymbosum L.) grown on sawdust-mulch-covered raised beds formed from sawdust-incorporated tilled soil. The differences in air temperature between tubes and ambient were consistent with those reported in the literature. Air temperature in translucent tubes was up to 19.7 °C higher than ambient. Differences in vapor pressure deficit were largely a function of differences in air temperature between tubes and ambient rather than actual vapor pressure. Stem temperatures were highest outside of the tubes as a result of radiation load. The surface temperature of ambient sawdust mulch (maximum 53 °C) was up to 14 °C above that in the translucent tube and 20 °C above that in the opaque tube. The largest gradients in the bed system were between the loose dry mulch and the soil–mulch interface. The presence of a grow tube did not influence soil temperature or its daily amplitude at 15 cm below the surface—the native tilled soil. Temperatures associated with the opaque tubes were between ambient and those in the translucent tubes. The temperature data indicate that both opaque and translucent unventilated grow tubes should influence shoot and crown growth but may have little influence on root growth in this shallow-rooted plant.

scholarly journals Microclimate under different shading screens in greenhouses cultivated with bromeliads

2012 ◽  
Vol 16 (8) ◽  
pp. 858-863 ◽  
Author(s):  
Ester Holcman ◽  
Paulo C. Sentelhas
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Air Temperature ◽  
Photosynthetically Active Radiation ◽  
External Condition ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Net Radiation ◽  
Active Radiation ◽  
Incoming Solar Radiation

This study had as its objective the evaluation of the influence of shading screens of different colors on the different microclimate variables in a greenhouse covered with transparent low-density polyethylene (LDPE). The experiment was conducted with five treatments: thermo-reflective screen (T1); a control - without screen (T2); red screen (T3); blue screen (T4); and black screen (T5), all of them with 70% of shading. An automatic micrometeorological station was installed in each treatment, measuring air temperature (T), relative humidity (RH), incoming solar radiation (Rg), photosynthetically active radiation (PAR) and net radiation (Rn) continuously. The control (T2) and red screen (T3) treatments promoted the highest solar radiation transmissivity, respectively 56.3 and 27%. The black screen (T5) had the lowest solar radiation transmissivity (10.4%). For PAR and Rn the same tendency was observed. The highest temperature was observed under blue screen (T4) treatment, which was 1.3 °C higher than external condition. Blue screen (T4) treatment also presented the highest relative humidity difference between inside and outside conditions.

scholarly journals Effects of External Coloured Shade Nets on Sweet Peppers Cultivated in Walk-in Plastic Tunnels

2015 ◽  
Vol 43 (2) ◽  
pp. 398-403 ◽  
Author(s):  
Attila OMBÓDI ◽  
Zoltán PÉK ◽  
Péter SZUVANDZSIEV ◽  
Zsuzsanna TÓTHNÉ TASKOVICS ◽  
Ambrus KOHÁZI-KIS ◽  
...  
Keyword(s):  
Chlorophyll Content ◽  
Air Temperature ◽  
Photosynthetically Active Radiation ◽  
Incident Radiation ◽  
Climatic Conditions ◽  
Active Radiation ◽  
Negative Relation ◽  
Spad Value ◽  
Positive Linear Relation ◽  
Relative Chlorophyll Content

Shading effect of external nets of different colours (white, green, yellow and red) on the yield of two “kapija” pepper (Capsicum anuum L.) cultivars was examined in walk-in plastic tunnels in Hungary under real cultivation circumstances. Shading nets decreased incoming radiation by 23-39% and reduced photosynthetically active radiation by 32-46%. The highest retention was obtained by yellow and green nets, in the range of 450-550 nm and 550-670 nm, respectively. Relation was reported between the degree of shading and the average air temperature of the tunnels, however, treatments did not decrease tunnel air temperature significantly, compared to that of unshaded and paint-shaded control tunnels. This can be explained by the applied proper ventilation and mist irrigation. A strong and negative relation was noted between the intensity of shading and the relative chlorophyll content (SPAD value) of leaves. Shading net treatments did not increase yields, yellow and green nets even decreased it. Instead of tunnel air temperature, yield was mainly affected by photosynthetically active radiation in the experiment. Strong positive linear relation was declared between the chlorophyll content of the leaves and the yield. Results of the current research led to the conclusions that under Hungarian climatic conditions the use of shading nets was less justified if proper cooling techniques (ventilation and mist irrigation) were applied; even under the relatively high incident radiation experienced during the trials. In greenhouses of less favourable climatic conditions, red or white shading nets are recommended instead of commonly used green ones in Hungary.

scholarly journals Does evaporation paradox exist in China?

2009 ◽  
Vol 13 (3) ◽  
pp. 357-366 ◽  
Author(s):  
Z. T. Cong ◽  
D. W. Yang ◽  
G. H. Ni
Keyword(s):  
Vapor Pressure ◽  
Air Temperature ◽  
Vapor Pressure Deficit ◽  
Sunshine Duration ◽  
Warming Trend ◽  
Pan Evaporation ◽  
Weather Factors ◽  
The Past ◽  
Weather Stations ◽  
Rate Of Evaporation

Abstract. One expected consequence of global warming is the increase in evaporation. However, lots of observations show that the rate of evaporation from open pans of water has been steadily decreasing all over the world in the past 50 years. The contrast between expectation and observation is called "evaporation paradox". Based on data from 317 weather stations in China from 1956 to 2005, the trends of pan evaporation and air temperature were obtained and evaporation paradox was analyzed. The conclusions include: (1) From 1956 to 2005, pan evaporation paradox existed in China as a whole while pan evaporation kept decreasing and air temperature became warmer and warmer, but it does not apply to Northeast and Southeast China; (2) From 1956 to 1985, pan evaporation paradox existed narrowly as a whole with unobvious climate warming trend, but it does not apply to Northeast China; (3) From 1986 to 2005, in the past 20 years, pan evaporation paradox did not exist for the whole period while pan evaporation kept increasing, although it existed in South China. Furthermore, the trend of other weather factors including sunshine duration, windspeed, humidity and vapor pressure deficit, and their relations with pan evaporation are discussed. As a result, it can be concluded that pan evaporation decreasing is caused by the decreasing in radiation and wind speed before 1985 and pan evaporation increasing is caused by the decreasing in vapor pressure deficit due to strong warming after 1986. With the Budyko curve, it can be concluded that the actual evaporation decreased in the former 30 years and increased in the latter 20 year for the whole China.

scholarly journals Spatiotemporal Variations and Influencing Factors of Terrestrial Evapotranspiration and Its Components during Different Impoundment Periods in the Three Gorges Reservoir Area

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2111
Author(s):  
Yongyue Ji ◽  
Qingqing Tang ◽  
Lingyun Yan ◽  
Shengjun Wu ◽  
Liming Yan ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Air Temperature ◽  
Three Gorges Reservoir ◽  
Vapor Pressure Deficit ◽  
Three Gorges Reservoir Area ◽  
Three Gorges ◽  
Climate Factors ◽  
Spatiotemporal Variations ◽  
Reservoir Area ◽  
The Three Gorges

Identifying the spatiotemporal variations and influencing climate factors of evapotranspiration (ET) and its components (vegetation transpiration (Ec), soil evaporation (Es), and canopy interception evaporation (Ei)) can greatly improve our understanding of water cycle, carbon cycle, and biogeochemical processes in a warming climate. As the world′s largest hydropower project, the construction of the Three Gorges Project (TGP) coupled with the significant land use/land cover change affected the regional water and energy exchange in the Three Gorges Reservoir Area (TGRA). This study aimed to reveal the spatiotemporal variations and influencing climate factors in ET and its components using PML-V2 products in TGRA during 2000–2020. Results showed that the mean annual ET, Ec, Es, and Ei in TGRA were 585.12, 328.49, 173.07, and 83.56 mm, respectively. The temporal variation of ET was dominated by Ec, with no significant change in the time trend. Es decreased (2.92 mm/y) and Ei increased (1.66 mm/y) significantly mainly in the cultivated land. ET, Ec, and Ei showed a similar seasonal variation pattern with a single peak, while Es presented a bimodal pattern. From the pre-impoundment to the first impoundment period, ET and Ec mainly increased in the head of TGRA, meanwhile, Es in urban area increased significantly by 27.8%. In the subsequent impoundment periods, ET and Ec changed slightly while Es sharply decreased. The Ei increased persistently during different impoundment period. The dominant climate factors affecting changes in Ec and Es were air temperature, vapor pressure deficit, and sunshine hours, while the variation of Ei was mainly affected by air temperature, vapor pressure deficit, and precipitation.

scholarly journals DESEMPENHO DE UM SISTEMA DE RESFRIAMENTO EVAPORATIVO DO AR EM CASA-DE-VEGETAÇÃO

Irriga ◽  
2010 ◽  
Vol 15 (2) ◽  
pp. 140-150
Author(s):  
Antonio José Steidle Neto ◽  
SÉRGIO ZOLNIER
Keyword(s):  
Vapor Pressure ◽  
Air Temperature ◽  
Vapor Pressure Deficit ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Climatic Conditions ◽  
Air Cooling ◽  
Cooling Efficiency ◽  
Growing Period ◽  
Air Cooling System

Este trabalho foi conduzido com o objetivo de analisar o desempenho de um sistema de resfriamento evaporativo do ar (tipo painel-exaustor) em casa-de-vegetação, ao longo do período diurno em dias com condições climáticas distintas. Foram realizadas medições de temperatura e umidade relativa do ar no interior e exterior de uma casa-de-vegetação durante o período de crescimento e desenvolvimento de tomateiros cultivados em substrato de areia. Verificou-se que as eficiências médias diárias de resfriamento evaporativo do ar variaram entre 74% e 81%. Os decréscimos máximos na temperatura do ar, imediatamente após a sua passagem pelo painel de celulose, foram de 8,2ºC e 11,4ºC. Observou-se ainda que, a eficiência de resfriamento do ar foi sensivelmente melhorada quando o déficit de pressão de vapor d'água do ar externo foi superior a 1,8 kPa.   UNITERMOS: déficit de pressão de vapor d'água do ar, temperatura do ar, eficiência de resfriamento evaporativo.     STEIDLE NETO, A. J.; ZOLNIER, S. EVAPORATIVE AIR COOLING SYSTEM PERFORMANCE IN A GREENHOUSE     2 ABSTRACT   This work aimed to analyze the performance of an evaporative air cooling system (pad-fan type) in greenhouse along daytime period in days with different climatic conditions. Air temperature and relative humidity measurements inside and outside of an greenhouse were made during the growing period of tomato plants cultivated in sand substrate. It was verified that the average daily evaporative cooling efficiency ranged from 74% to 81%. The maximum air temperature decrements, immediately after its passage through the cellulose pad, were 8.2°C and 11.4°C. It was also observed that the air cooling efficiency was sensitively improved when the vapor pressure deficit of the external air was higher than 1.8 kPa.   KEYWORDS: vapor pressure deficit, air temperature, evaporative cooling efficiency.  

scholarly journals Microclimatic characterization of a conilon coffee plantation grown in an east-west orientation

2020 ◽  
pp. 431-438
Author(s):  
Ana Paula Pereira Bis ◽  
Fábio Luiz Partelli ◽  
Antelmo Ralph Falqueto ◽  
Weverton Pereira Rodrigues ◽  
Henrique Duarte Vieira
Keyword(s):  
Plant Growth ◽  
Vapor Pressure ◽  
Air Temperature ◽  
Vapor Pressure Deficit ◽  
Leaf Temperature ◽  
Plant Performance ◽  
The North ◽  
North Side ◽  
Significant Difference ◽  
East West

Plant microclimate is seasonally influenced by the Earth’s rotation and the orientation of sun-exposed slopes. As such, understanding the system which constitutes the microenvironment is essential to create strategies to optimize plant performance in a changing environment. The objective of this work was to evaluate the influence of planting coffee in an east-west orientation on microclimatic aspects, plant growth and nutrient content. The experiment was conducted in a farm located in the northern region of the State of Espírito Santo, Brazil. Data collection was carried out on a 30-month old conilon coffee crop under full sun, with spacing of 3.0 m x 1.0 m and a plant height of ca. 1.6 m, from December 2016-September 2017. The irradiance, air temperature and vapor pressure deficit variables were reported by means of external data loggers. Leaf temperature (determined using thermal images), plant growth and leaf concentration on both sides of the plant were evaluated. Highest irradiance, air temperature and vapor pressure deficit values were observed on the north side, with the maximal difference reaching 4°C. This microclimate led to the highest leaf temperature on the north side, with a maximal difference of ca. 11°C around midday. Differences in macro- and micronutrient leaf concentrations were observed with a trend toward higher values on the north side probably associated with increased transpiration rates due to a high vapor pressure deficit. Higher macro- and micronutrient leaf content led to the better performance of coffee plants on the north side to some extent. There was no significant difference between the two sides of the plant for the growth variables.

Sign in / Sign up

Export Citation Format

Share Document