scholarly journals Alternative conifer release treatments affect below- and near-ground microclimate

1997 ◽  
Vol 73 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Phillip E. Reynolds ◽  
Donald A. Buckley ◽  
James A. Simpson ◽  
Andrew M. Gordon ◽  
Donald A. Gresch ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Relative Humidity ◽  
Photosynthetically Active Radiation ◽  
Forest Floor ◽  
Growing Season ◽  
Active Radiation ◽  
Soil Temperatures ◽  
Glyphosate Herbicide ◽  
And Control ◽  
Thermistor Resistance

Li-Cor weather stations and thermistor/resistance soil cells were used during 1994 to monitor microclimate in young spruce plantations during the first growing season after the following replicated alternative conifer release treatments [brush saw, Silvana Selective, Release® (a.i., triclopyr) herbicide. Vision® (a.i., glyphosate) herbicide], and control (no treatment) were applied. Treatments were conducted in mid-August (herbicides) and late October and early November (cutting) 1993. In 1994, temperature, photosynthetically-active radiation (PAR), and relative humidity (RH) were monitored near (0.25 m) and above (2 m) the forest floor. Fiberglass thermistor/resistance soils cells were installed 15 and 30 cm deep, and soil moisture and temperature were read bimonthly. In relation to controls, PAR near and above the forest floor increased on all conifer release treatments. By July, PAR near the forest floor declined on both the cut and herbicide treatments. That decline occurred in early July for the brush saw treatment, but in late July for the Vision® treatment. PAR at 2 m was similar among conifer release alternatives and significantly greater than for controls throughout the growing season. Increased solar radiation resulted in significant soil warming following the conifer release treatments. During the growing season, duff (5 cm) and mineral (15 cm) soil temperatures were highest for the Vision® and Release® treatments, and lower on the brush saw and control treatments. November soil temperatures were slightly cooler in released than control plots. Frequent rains resulted in relatively high RH and soil moisture readings during the 1994 growing season. Relative humidity near the forest floor was lowest for the Vision®, intermediate for the brush saw, and highest for the control treatments. During the growing season after treatments, soil moisture levels were higher on treated than control plots. Key words: microclimate, alternative conifer release treatments, Fallingsnow Ecosystem Project, photosynthetically-active radiation (PAR), soil temperature and moisture, relative humidity, ecosystem study

scholarly journals Effect of Coloured Agro-Net Covers on Insect Pest Control and Yield of Tomato (Solanum lycopersicon Mill)

2017 ◽  
Vol 9 (12) ◽  
pp. 283
Author(s):  
Langàt Jelagat Caroline ◽  
Mwanarusi Saidi ◽  
Arnold Opiyo
Keyword(s):  
Soil Moisture ◽  
Relative Humidity ◽  
Photosynthetically Active Radiation ◽  
Block Design ◽  
Control Treatment ◽  
Solanum Lycopersicon ◽  
Tomato Production ◽  
Tomato Plants ◽  
Active Radiation ◽  
Neutral Colour

Tomato (Solanum lycopersicon Mill) is one of the most important vegetable crops consumed throughout the world; and is rich in important vitamins, minerals and antioxidants. Production of the crop in open fields is however constrained by several biotic and abiotic stresses that lead to low tomato yields and quality. This study aimed at determining the effects of coloured agro-net covers on microclimate, pest infestation and yield of tomato cultivar ‘‘Rio Grande’’. The study consisted of two trials conducted using a randomized complete block design (RCBD) with five replications and six treatments. Tomato plants were grown under blue, yellow, grey, white or multi-coloured net covers with a no net cover as the control. Data were collected on microclimate (temperature, soil moisture, relative humidity and photosynthetically active radiation), pest counts and crop yield variables. Net covering modified the tomato crop microclimate with highest temperatures and soil moisture and, relative humidity levels recorded under white (21.03 oC), blue (30.03%) and multi-coloured net covers (76.26%), respectively compared to the no net control treatment (16.32 oC, 14.82% and 64.90%). Photosynthetically active radiation (PAR) was lowest under the blue agro-net cover (416.09 µmol m-2 s-1) and highest under control treatment (985.00 µmol m-2 s-1). Tomato plants grown under coloured-colour nets (yellow and blue) had lower population of silverleaf whitefly, thrips and aphids while mite population was lower under neutral-colour net covers (white, grey and multi-coloured). The neutral-colour net covers (24938.87, 19525.16 and 21541.93 kg/ha) resulted in higher yields compared to coloured-colour net covers (16804.62 and 14551.05 kg/ha). Results of the study indicate that use of agro-net covers especially the neutral-colour net cover can improve microclimate, protect tomato against insect pests and can be considered a viable strategy for tomato production by smallholder growers.

scholarly journals Development of Suitable Microclimate Using Low˗tech Greenhouse for Off-Season Production of High Value Crops in Bangladesh

2021 ◽  
Vol 3 (6) ◽  
pp. 95-103
Author(s):  
M. A. Awal ◽  
P. C. Dhar ◽  
M. H. R. Pramanik
Keyword(s):  
Relative Humidity ◽  
Film Thickness ◽  
Air Temperature ◽  
Photosynthetically Active Radiation ◽  
Crop Production ◽  
Active Radiation ◽  
Horticultural Crops ◽  
Season Extension ◽  
Soil Temperatures ◽  
Solar Noon

Low˗tech greenhouses (low˗techs) have been used globally to cultivate horticultural crops since many years, but their utilization in Bangladesh is a recent phenomenon. Moreover, information on altered microclimate inside the low˗tech is hardly reported. An investigation has been conducted in the Crop Botany Field Laboratory, Bangladesh Agricultural University (24o72´N, 90o43´E and 18 masl), Mymensingh during the late autumn to winter seasons from mid-October to mid-February of 2015/16, 2016/17 and 2017/18 years to find out the variation in microclimatic parameters between inside and outside of low˗techs and to evaluate the suitability of altered microclimate inside the low˗techs for off˗season production of high value crops in Bangladesh. Three low˗techs were erected in each year using bamboo frame covered with single inflated polyethylene film (thickness = 0.2 mm). Major microclimatic parameters inside and aside outside the low˗techs were measured with standard devices or techniques. Around 30 percent incoming photosynthetically active radiation (PAR) was cut˗off by low˗tech cover during solar noon when the sun’s zenith gets minimum value (around 0o). However, this cut˗off portion of PAR was gradually increased with the sunrise and sunset when zenith is around 90o. During the daytime, low˗tech retains higher air temperature than that found at outside and the differences in air temperature between inside and outside of low˗techs was gradually increased after sunrise with a peak difference of 7 to 9 oC following the solar noon (i.e., 13:00-14:00 hour). No distinct variation in relative humidity was recorded between inside and outside of the low˗tech. Low˗tech cover retains higher soil temperature than that was recorded in outside. The variation of both air and soil temperatures between inside and outside of low˗techs was higher during the daytime but lower at nighttime or even at daytime when the sky remained overcast. The variation in microclimatic parameters under low˗techs not only protect the growing crops from climate vagaries during autumn, winter and spring seasons but also provide suitable warmer environment for growing many high value crops during that seasons and thus crop production in off˗season and/or season extension benefits can easily be achieved by low˗techs.

scholarly journals Simulated Transport, Postproduction Irradiance Influence Postproduction Performance of Potted Roses

HortScience ◽  
1991 ◽  
Vol 26 (11) ◽  
pp. 1401-1404 ◽  
Author(s):  
Terril A. Nell ◽  
Cor Vonk Noordegraaf
Keyword(s):  
Relative Humidity ◽  
Photosynthetically Active Radiation ◽  
Active Radiation ◽  
Irradiance Level ◽  
Fluorescent Lamps ◽  
Level 1

Three simulated transport temperatures (5, 11, or 17C) and durations. (3, 6, or 9 days) were used to evaluate the postproduction flowering patterns of miniature potted rose (Rosa sp) `Orange Rosamini'. The postproduction environment was maintained at 20 ± lC, 60% ± 5% relative humidity (RI-I), and an irradiance level, from cool-white fluorescent lamps, of 4.5 W·m-2 photosynthetically active radiation (PAR) for 12 hours daily to simulate conditions at the retail or consumer level. At 3 weeks postproduction, plants held for 9 days at 17C had the fewest buds showing color per plant. As temperature increased, there were fewer flowers per plant at weeks 2 and 3 of postproduction. In a second study, the effect of simulated transport (3 days at 5C vs. no transport) and postproduction irradiance level (1, 2, or 4 W·m-2 PAR) were evaluated over a 7-week postproduction period for `Orange Rosamini'. A three-way interaction was observed between simulated transport treatment, postproduction irradiance level, and time in postproduction for the number of open flowers per plant. Plants responded similarly at 1 and 2 W·m2 throughout the postproduction period, regardless of transport treatment; however, at 4 W·m-2 the plants of the no transport treatment had two to three open flowers each week up to week 6 of postproduction, while plants subjected to simulated transport followed the pattern of one and two open flowers for 0 to 3 weeks. Flowering then increased to three to four open flowers for the duration of the postproduction period. A third study involved two simulated transport treatments (3 days at SC vs. no transport), three postproduction irradiance levels (1, 2, and 4 W·m-2 PAR), and six miniature rose cultivars (`Orange Rosamini', `Red Minimo' `Sweet Rosamini', `Golden Rosamini', `Favorite Rosamini', and `White Rosamini'). Plants held at 1 or 2 W·m-2 for 3 weeks had no open flowers, while those held at 4 W·m-2 for 3 weeks had one to four open flowers, except `Sweet Rosamini', which had no open flowers with simulated transport.

Relationship of soil moisture with solar-induced chlorophyll fluorescence and normalized difference vegetation index in different phenological stages

2020 ◽  
Author(s):  
Qiu Shen ◽  
Jianjun Wu ◽  
Leizhen Liu ◽  
Wenhui Zhao
Keyword(s):  
Soil Moisture ◽  
Chlorophyll Fluorescence ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Growing Season ◽  
Maturity Stage ◽  
Phenological Stages ◽  
Active Radiation ◽  
Relationship Of ◽  
The Relationship

<p>As an important part of water cycle in terrestrial ecosystem, soil moisture (SM) provides essential raw materials for vegetation photosynthesis, and its changes can affect the photosynthesis process and further affect vegetation growth and development. Thus, SM is always used to detect vegetation water stress and agricultural drought. Solar-induced chlorophyll fluorescence (SIF) is signal with close ties to photosynthesis and the normalized difference vegetation index (NDVI) can reflect the photosynthetic characteristics and photosynthetic yield of vegetations. However, there are few studies looking at the sensitivity of SIF and NDVI to SM changes over the entire growing season that includes multiple phenological stages. By making use of GLDAS-2 SM products along with GOME-2 SIF products and MODIS NDVI products, we discussed the detailed differences in the relationship of SM with SIF and NDVI in different phenological stages for a case study of Northeast China in 2014. Our results show that SIF integrates information from the fraction of photosynthetically active radiation (fPAR), photosynthetically active radiation (PAR) and SIF<sub>yield</sub>, and is more effective than NDVI for monitoring the spatial extension and temporal dynamics of SM on a short time scale during the entire growing season. Especially, SIF<sub>PAR_norm</sub> is the most sensitive to SM changes for eliminating the effects of seasonal variations in PAR. The relationship of SM with SIF and NDVI varies for different vegetation cover types and phenological stages. SIF is more sensitive to SM changes of grasslands in the maturity stage and  rainfed croplands  in the senescence stage than NDVI, and it has significant sensitivities to SM changes of forests in different phenological stages. The sensitivity of SIF and NDVI to SM changes in the senescence stages stems from the fact that vegetation photosynthesis is relatively weaker at this time than that in the maturity stage, and vegetations in the reproductive growth stage still need much water. Relevant results are of great significance to further understand the application of SIF in SM detection.</p>

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.

Common Ragweed (Ambrosia artemisiifolia) Interference in Soybeans (Glycine max)

Weed Science ◽  
1981 ◽  
Vol 29 (3) ◽  
pp. 339-342 ◽  
Author(s):  
H. D. Coble ◽  
F. M. Williams ◽  
R. L. Ritter
Keyword(s):  
Glycine Max ◽  
Natural Population ◽  
Photosynthetically Active Radiation ◽  
Yield Loss ◽  
Damage Threshold ◽  
Growing Season ◽  
Ambrosia Artemisiifolia ◽  
Common Ragweed ◽  
Active Radiation ◽  
Naturally Occurring

The influence of common ragweed (Ambrosia artemisiifoliaL.) interference on soybean [Glycine max(L.) Merr. ‘Ransom’] yield was studied in the field utilizing naturally occurring weed populations. The damage-threshold population for a full-season, in-row common ragweed infestation was four weeds/10 m of row, which resulted in an 8% yield loss. Soybeans kept weed-free for 2 weeks or longer after emergence in a dry year produced normal yields, but 4 weeks of weed-free maintenance was required when adequate moisture was available early in the growing season. Soybean yield was not reduced by a natural population of common ragweed if the period of interference was limited to 6 weeks or less after crop emergence. By 8 weeks after emergence, common ragweed height averaged 25 cm taller than soybeans, and the weed canopy intercepted 24% of the photosynthetically active radiation.

Vegetation management and site preparation effects on 13C isotopic composition in planted white spruce

2001 ◽  
Vol 31 (6) ◽  
pp. 1093-1097 ◽  
Author(s):  
Thomas E Staples ◽  
Ken CJ Van Rees ◽  
J Diane Knight ◽  
C van Kessel
Keyword(s):  
Soil Moisture ◽  
Picea Glauca ◽  
White Spruce ◽  
Vegetation Management ◽  
Site Preparation ◽  
Native Vegetation ◽  
Active Radiation ◽  
Growing Seasons ◽  
Initial Hypothesis ◽  
And Control

Moisture availability is the factor that most commonly influences the discrimination against 13C fixation (Δ) by C3 plants. Therefore, by changing the availability of moisture by way of controlling competing vegetation, Δ in white spruce (Picea glauca (Moench) Voss) seedlings should be affected. The objective of this study was to determine the influence of manual brushing on Δ in white spruce seedlings planted in disc-trenched and control (i.e., no site preparation) microsites. The effects of site preparation and vegetation management on soil moisture, photosynthetically active radiation (PAR), and Δ in white spruce seedlings were evaluated over three growing seasons. Vegetation management increased the amount of PAR reaching seedlings in the control and disc-trenched treatments by removing the shading by native vegetation around each seedling. It appears that the increase in PAR reaching seedlings decreased Δ by increasing the photosynthetic consumption of CO2. Differences in soil available moisture (up to 22%) between control and disc-trenched treatments were not reflected in Δ values, contrary to our initial hypothesis. This may indicate that the site was not moisture limiting. Also, these results underline the complexity and difficulty of determining the controlling mechanisms by which Δ is affected.

scholarly journals Transmittance of young Norway spruce stand canopy for photosynthetically active radiation during the growing season

2013 ◽  
Vol 61 (1) ◽  
pp. 129-135
Author(s):  
Irena Marková ◽  
Jiří Kubásek
Keyword(s):  
Norway Spruce ◽  
Photosynthetically Active Radiation ◽  
Stand Structure ◽  
Growing Season ◽  
Stand Development ◽  
The Czech Republic ◽  
Active Radiation ◽  
The Mean ◽  
Sky Conditions ◽  
Phenological Phases

Analysis of transmittance of young Norway spruce stand canopy for photosynthetically active radiation (PAR) was made at the study site of Bílý Kříž (the Moravian-Silesian Beskids Mts., the Czech Republic) at different sky conditions during the growing season in 2010. For the description of PAR transmittance different phenological phases of the spruce stand development in clear and overcast days were chosen. The mean daily PAR transmittance of the spruce canopy was significantly higher in overcast days compared with clear ones. Diffuse PAR thus penetrated into lower parts of the canopy more efficiently than direct one. PAR transmittance of young Norway spruce stand canopy was different in individual phenological phases of the spruce stand canopy which was caused by changes in the stand structure during the growing season. Thus monitoring of transmittance of young Norway spruce stand canopy for PAR can help to describe the development of spruce stand canopy.

scholarly journals A Whole-plant, Open, Gas-exchange System for Measuring Net Photosynthesis of Potted Woody Plants

HortScience ◽  
1996 ◽  
Vol 31 (6) ◽  
pp. 944-946 ◽  
Author(s):  
D.P. Miller ◽  
G.S. Howell ◽  
J.A. Flore
Keyword(s):  
Gas Exchange ◽  
Photosynthetically Active Radiation ◽  
Woody Plants ◽  
Net Photosynthesis ◽  
Growing Season ◽  
Exchange System ◽  
Active Radiation ◽  
Whole Plant ◽  
Short Period ◽  
Gas Exchange System

Chambers were constructed to measure gas exchange of entire potted grapevines (Vitis vinifera L.). The plant enclosures were constructed from Mylar film, which is nearly transparent to photosynthetically active radiation. Maintaining a slight, positive, internal pressure allowed the Mylar chambers to inflate like balloons and required no other means of support. The whole-plant, gas-exchange chamber design and construction were simple and inexpensive. They were assembled easily, equilibrated quickly, and did not require cooling. They allowed for the measurement of many plants in a relatively short period. This system would enable the researcher to make replicated comparisons of treatment influences on whole-plant CO2 assimilation throughout the growing season. While CO2 measurement was the focus of this project, it would be possible to measure whole-plant transpiration with this system.

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