scholarly journals Sowing operation direction and population densities in corn growing

2019 ◽  
Vol 23 (3) ◽  
pp. 183-187
Author(s):  
Rafael D. G. Corrêa ◽  
Carlos E. A. Furlani ◽  
Cristiano Zerbato ◽  
Danilo T. de Oliveira ◽  
Rafael H. de F. Noronha ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Photosynthetically Active Radiation ◽  
Corn Yield ◽  
Population Densities ◽  
Plant Populations ◽  
Hybrid Corn ◽  
Active Radiation ◽  
Plant Densities ◽  
Lower Plant ◽  
East West

ABSTRACT Among the factors that may influence corn yield are sowing operation direction and plant population, since they alter the shade index between crop rows, and consequently the efficiency of interception of the photosynthetically active radiation by the leaves of plants. The aim of this study was to evaluate the influence of sowing direction and plant populations on P2830VYH hybrid corn yield. The experiment was conducted at the facilities of FCAV-UNESP, latitude 21º 14’ S and longitude 48º 16’ W in Jaboticabal (SP). The treatments were composed of three sowing directions (North-South, Northeast-Southwest, and East-West) and three population densities (40,000, 60,000 and 80,000 plants ha-1). The treatment with 80,000 plants ha-1 had the lowest cost per sack of corn and profitability 21% higher than that of the treatment with 60,000 plants ha-1, and 45% higher than that of the treatment with 40,000 plants ha-1. Sowing direction had no influence on grain yield when environmental conditions were favorable to the development of the crop. Lower plant densities lead to higher individual results in relation to the number of cobs, length of cobs and number of grains per row.

scholarly journals Cumulative Effects of Ultraviolet Radiation and Photosyntheically Active Radiation on Phycobiliproteins of A Hot-Spring Cyanobacatrium Nostoc sp. strain HKAR-2

2016 ◽  
Vol 4 (3) ◽  
pp. 247-253
Author(s):  
Vinod K. Kannaujiya ◽  
Akhlaqur Rahman ◽  
. Adinath ◽  
Arun S. Sonker ◽  
Jainendra Pathak ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Environmental Conditions ◽  
Photosynthetically Active Radiation ◽  
Biomedical Applications ◽  
Hot Spring ◽  
Ultraviolet B ◽  
Cumulative Effects ◽  
Key Factors ◽  
Active Radiation ◽  
Continuous Induction

Cyanobacteria are cosmopolitan in distribution and have adapted to diverse habitats. Adaptation of cyanobacteria is one of the key factors to withstand harsh environmental conditions. We have investigated the effects of photosynthetically active radiation (PAR; 400–700 nm), ultraviolet-B (UV-B; 280–315 nm) radiation and PAR+UV-B radiations on phycobiliproteins (PBPs) of a hot-spring cyanobacterium Nostoc sp. HKAR-2. There was a continuous induction of both phycoerythrin (PE) and phycocyanin (PC) after exposure of PAR up to 300 min. However, there was an induction in the synthesis of both PE and PC up to 240 min exposure of UV-B and PAR+UV-B radiations. Further exposure showed decline in the synthesis due to rapid uncoupling, bleaching and degradation of PBPs. Similarly, emission fluorescence also showed an induction with a shift towards longer wavelengths after 240 min of UV-B and PAR+UV-B exposure. These results indicate that short duration of UV radiation may promote the synthesis of PBPs that can be utilized in various biotechnological and biomedical applications. Int J Appl Sci Biotechnol, Vol 4(3): 247-253

Modelling the interception of photosynthetically active radiation by evergreen subtropical hedgerows

2007 ◽  
Vol 58 (3) ◽  
pp. 215 ◽  
Author(s):  
Trevor Olesen ◽  
Stephen Morris ◽  
Lisa McFadyen
Keyword(s):  
Photosynthetically Active Radiation ◽  
Crop Yields ◽  
Maximum Yield ◽  
Curvilinear Relationship ◽  
Tree Crops ◽  
Canopy Development ◽  
Active Radiation ◽  
The North ◽  
Explained Variance ◽  
East West

Horticultural tree crop yields tend to be linearly correlated with the percentage of photosynthetically active radiation (PAR) intercepted by the canopies, at least for part of the PAR interception range. Models of PAR interception by hedgerows have been used in the design of orchards for temperate tree crops, especially apples, but not for subtropical tree crops, such as lychee and macadamia. Subtropical crops need special consideration because of the latitudes at which they are grown, the specific shapes and dimensions of the hedgerows, and the evergreen habit, which requires an understanding of the entire annual cycle. We present outputs from a PAR interception model for solid rectangular and tapered hedgerows, based on a model of irradiation beneath blue skies. Annual PAR interception tends to decline as row orientation rotates from north–south to east–west, but with some exceptions for particular tree geometries, and declines slightly with decreasing latitude. Daily PAR interception is also affected by row orientation, with little seasonal variation for north–south rows but large fluctuations for east–west rows, including very high interception in winter and low interception in summer. Row orientation and tree shape greatly affect the distribution of PAR over the surface of the canopy. For example, the side faces of evenly spaced, symmetrical, identical north–south hedgerows are equally irradiated throughout the year, but there can be large seasonal differences in the relative irradiance of the north and south faces of the same hedgerows aligned east–west. The solid tapered hedgerow model tended to overestimate measured PAR interception by ~6% overall, but the percent overestimation seemed to vary with PAR interception, being greater at lower levels of PAR interception. A curvilinear relationship was found between the yield of macadamia in the Northern Rivers area of NSW in 1997 and the measured PAR intercepted by the trees, with an explained variance of 50%. Maximum yield occurred at ~86% PAR interception. Using modelled PAR interception the explained variance of the yield was 34%. Model estimates of PAR interception were close to those measured and might be used to address a range of physiological questions concerning the canopy development of subtropical hedgerows.

Effect of the apetalous flower character on radiation distribution in the crop canopy, yield and its components in oilseed rape (Brassica napus)

1991 ◽  
Vol 117 (2) ◽  
pp. 189-196 ◽  
Author(s):  
M. S. S. Rao ◽  
N. J. Mendham ◽  
G. C. Buzza
Keyword(s):  
Brassica Napus ◽  
Population Density ◽  
Short Wave ◽  
Wave Radiation ◽  
Crop Canopy ◽  
Population Densities ◽  
Short Wave Radiation ◽  
Plant Populations ◽  
Radiation Distribution ◽  
Lower Plant

SUMMARYA Brassica napus line that produces flowers with virtually no petals (Apetalous) was compared for its physiological significance with Marnoo, a related cultivar bearing conventional yellow petals. Experiments between 1984 and 1987 used different growth regulators, plant population densities and irrigation treatments. Apetalous allowed 30 % more short-wave radiation to reach the base of the inflorescence, and reflected only half as much radiation as Marnoo at peak flowering. This allowed leaves to persist and remain active for longer. Apetalous then consistently retained more seeds/pod, each of greater mean weight, at all heights within the crop canopy, resulting in substantially greater yields than Marnoo in most instances. At the highest population density, it retained productive secondary branches, whereas Marnoo had none. Irrigation after flowering increased the yields of both lines by allowing more seeds/pod to be retained, particularly at lower heights in the canopy. In Apetalous, however, even without irrigation, yields remained high. Apetalous does have larger flower parts, other than petals, which could contribute to the larger pods and seeds. This, combined with lower plant populations than Marnoo in some experiments, could have explained some of the effects seen, but the characteristic is worthy of further study in a range of genetic backgrounds and environments.

scholarly journals Spatial Variability of Photosynthetically Active Radiation in a Greenhouse

1996 ◽  
Vol 121 (2) ◽  
pp. 321-325 ◽  
Author(s):  
E.A. Guertal ◽  
C.B. Elkins
Keyword(s):  
Spatial Correlation ◽  
Photosynthetically Active Radiation ◽  
Horizontal Line ◽  
Active Radiation ◽  
Spatially Correlated ◽  
The North ◽  
Gable Roof ◽  
Contour Plots ◽  
Data Points ◽  
East West

Photosynthetically active radiation (PAR) was measured at two times of day (8:00 am and noon Central Standard Time) in a 915 × 915-cm area of a 1006 × 915-cm gable roof greenhouse. PAR measurements were taken across a grid at 40-cm intervals, a total of 529 data points. Spatial variation of PAR in the greenhouse was evaluated through contour plots and the geostatistical technique of semivariogram construction. Semivariograms provide a visual guide to the degree of spatial correlation of a variable, allowing a quantification of the distance at which variables cease to be spatially correlated (the range) Measured PAR contained distinct zones of lowered values, a function of overhead greenhouse structures, wall-hung electrical boxes, and tall plants in adjacent greenhouses. Although the amount of PAR changed over time, zones of high and low PAR remained relatively constant, except at the sides of the greenhouse. Constructed semivariograms revealed that PAR contained strong spatial correlation (up to a 350-cm separation) as measured in the north-south direction, moving parallel to greenhouse bench placement. When PAR measurements perpendicular to benches (east-west) were used in directional semivariograms PAR was found to be completely random, plotting as a horizontal line called a nugget effect. Thus, plants placed perpendicular to the greenhouse benches (east-west) would not be affected by the spatial correlation of PAR.

scholarly journals Reflective material on cultivation benches and rice straw over the substrate in papaya seedling production

2020 ◽  
Vol 11 (8) ◽  
pp. 1713-1723
Author(s):  
Rogério Do Carmo Cabral ◽  
Daniele Ferreira Cavalcante ◽  
Eduardo Pradi Vendruscolo ◽  
Murilo Battistuzzi Martins ◽  
Tiago Zoz ◽  
...  
Keyword(s):  
Experimental Design ◽  
Rice Straw ◽  
Environmental Conditions ◽  
Photosynthetically Active Radiation ◽  
Aluminum Foil ◽  
Joint Analysis ◽  
Seedling Production ◽  
High Quality ◽  
Active Radiation ◽  
Randomized Experimental Design

Improving environmental conditions in the production of seedlings by expanding the distribution of photosynthetically active radiation in abaxial leaves and protecting the substrate with straw can promote the production of higher quality seedlings. This study aimed to evaluate the reflective materials over the cultivation bench and the use of rice straw over the substrate in the formation of papaya seedlings of the group ‘Formosa’. The joint analysis was performed considering a completely randomized experimental design in a 3 x 2 factorial scheme, with five replications and six seedlings per plot. The use of aluminized screen (Aluminet®) and aluminum foil with an area of 1 m x 1.2 m as reflective material on the cultivation bench and treatment without reflective material were evaluated. Also, the presence and absence of a rice straw layer with 5 cm height, as covering over the substrate were evaluated. In the benches with aluminum foil and without reflective material, the seedling production without rice straw over the substrate provided papaya seedlings of higher quality than the rice straw over the substrate. The aluminum foil produced high-quality papaya seedlings in the treatments with rice straw over the substrate. The aluminized screen on the cultivation bench was not favorable for the papaya seedlings production.

scholarly journals A microbiota–root–shoot circuit favours Arabidopsis growth over defence under suboptimal light

Nature Plants ◽  
2021 ◽  
Author(s):  
Shiji Hou ◽  
Thorsten Thiergart ◽  
Nathan Vannier ◽  
Fantin Mesny ◽  
Jörg Ziegler ◽  
...  
Keyword(s):  
Stress Responses ◽  
Photosynthetically Active Radiation ◽  
Bacterial Community Composition ◽  
Light Condition ◽  
Long Distance ◽  
Active Radiation ◽  
Light Manipulation ◽  
Growth Deficiency ◽  
Dependent Growth ◽  
Control Light

AbstractBidirectional root–shoot signalling is probably key in orchestrating stress responses and ensuring plant survival. Here, we show that Arabidopsis thaliana responses to microbial root commensals and light are interconnected along a microbiota–root–shoot axis. Microbiota and light manipulation experiments in a gnotobiotic plant system reveal that low photosynthetically active radiation perceived by leaves induces long-distance modulation of root bacterial communities but not fungal or oomycete communities. Reciprocally, microbial commensals alleviate plant growth deficiency under low photosynthetically active radiation. This growth rescue was associated with reduced microbiota-induced aboveground defence responses and altered resistance to foliar pathogens compared with the control light condition. Inspection of a set of A. thaliana mutants reveals that this microbiota- and light-dependent growth–defence trade-off is directly explained by belowground bacterial community composition and requires the host transcriptional regulator MYC2. Our work indicates that aboveground stress responses in plants can be modulated by signals from microbial root commensals.

scholarly journals Intercepted Photosynthetically Active Radiation (PAR) and Spatial and Temporal Distribution of Transmitted PAR under High-Density and Super High-Density Olive Orchards

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 351
Author(s):  
Adolfo Rosati ◽  
Damiano Marchionni ◽  
Dario Mantovani ◽  
Luigi Ponti ◽  
Franco Famiani
Keyword(s):  
Spatial Variability ◽  
Photosynthetically Active Radiation ◽  
Temporal Distribution ◽  
High Density ◽  
Radiation Use Efficiency ◽  
Spatial And Temporal Distribution ◽  
Active Radiation ◽  
Use Efficiency ◽  
And Performance ◽  
Radiation Use

We quantified the photosynthetically active radiation (PAR) interception in a high-density (HD) and a super high-density (SHD) or hedgerow olive system, by measuring the PAR transmitted under the canopy along transects at increasing distance from the tree rows. Transmitted PAR was measured every minute, then cumulated over the day and the season. The frequencies of the different PAR levels occurring during the day were calculated. SHD intercepted significantly but slightly less overall PAR than HD (0.57 ± 0.002 vs. 0.62 ± 0.03 of the PAR incident above the canopy) but had a much greater spatial variability of transmitted PAR (0.21 under the tree row, up to 0.59 in the alley center), compared to HD (range: 0.34–0.43). This corresponded to greater variability in the frequencies of daily PAR values, with the more shaded positions receiving greater frequencies of low PAR values. The much lower PAR level under the tree row in SHD, compared to any position in HD, implies greater self-shading in lower-canopy layers, despite similar overall interception. Therefore, knowing overall PAR interception does not allow an understanding of differences in PAR distribution on the ground and within the canopy and their possible effects on canopy radiation use efficiency (RUE) and performance, between different architectural systems.

scholarly journals Estimation of Incident Photosynthetically Active Radiation from GOES Visible Imagery

2008 ◽  
Vol 47 (3) ◽  
pp. 853-868 ◽  
Author(s):  
Tao Zheng ◽  
Shunlin Liang ◽  
Kaicun Wang
Keyword(s):  
Photosynthetically Active Radiation ◽  
Terrestrial Ecosystem ◽  
New Method ◽  
High Temporal Resolution ◽  
Atmospheric Conditions ◽  
Ecosystem Models ◽  
Surface Conditions ◽  
Active Radiation ◽  
Ground Measurement ◽  
Visible Imagery

Abstract Incident photosynthetically active radiation (PAR) is an important parameter for terrestrial ecosystem models. Because of its high temporal resolution, the Geostationary Operational Environmental Satellite (GOES) observations are very suited to catch the diurnal variation of PAR. In this paper, a new method is developed to derive PAR using GOES data. What makes this new method distinct from the existing method is that it does not need external knowledge of atmospheric conditions. The new method retrieves both atmospheric and surface conditions using only at-sensor radiance through interpolation of time series of observations. Validations against ground measurement are carried out at four “FLUXNET” sites. The values of RMSE of estimated and ground-measured instantaneous PAR at the four sites are 130.71, 131.44, 141.16, and 190.22 μmol m−2 s−1, respectively. At the four validation sites, the RMSE as the percentage of estimated mean PAR value are 9.52%, 13.01%, 13.92%, and 24.09%, respectively; the biases are −101.54, 16.56, 11.09, and 53.64 μmol m−2 s−1, respectively. The independence of external atmospheric information enables this method to be applicable to many situations in which external atmospheric information is not available. In addition, topographic impacts on surface PAR are examined at the 1-km resolution at which PAR is retrieved using the GOES visible band data.

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