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1
Groot, Arthur. "A model to estimate light interception by tree crowns, applied to black spruce". Canadian Journal of Forest Research 34, n. 4 (1 aprile 2004): 788–99. http://dx.doi.org/10.1139/x03-242.
Testo completoAbstract (sommario):
CORONA is a spatially explicit model designed to efficiently estimate the quantity of shortwave radiation intercepted by individual tree crowns. Radiation interception is determined from intersections of light rays with tree crowns for rays originating throughout the sky hemisphere. CORONA comprises a flexible, asymmetric description of crowns, a computationally efficient ray-tracing procedure, numerical solution of ray × crown intersections, and several alternative within-crown light interception functions. The interception functions were calibrated and evaluated in two plots located in black spruce (Picea mariana (Mill.) BSP) stands, where tree positions and crowns were mapped. An interception function using only the number of intercepting crowns (i.e., a hits function) generally resulted in better agreement between modelled and observed light levels than an interception function using the total path length through crowns. There was some evidence that transmission was greater in parts of crowns within low-light-level environments. This effect can be incorporated into an interception function for more realistic modelling of interception. Errors in crown description are likely the main cause of discrepancies between modelled and observed light levels on a half-hourly basis. The agreement between modelled and observed light levels on a daily basis indicates that CORONA can provide useful estimates of light interception by tree crowns.
2
Steven, M. D., P. V. Biscoe, K. W. Jaggard e J. Paruntu. "Foliage cover and radiation interception". Field Crops Research 13 (gennaio 1986): 75–87. http://dx.doi.org/10.1016/0378-4290(86)90012-2.
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A. K. MISHRA, PADMAKAR TRIPATHI, R. K. PAL e S. R. MISHRA. "Light interception and radiation use efficiency of wheat varieties as influenced by number of irrigations". Journal of Agrometeorology 11, n. 2 (1 dicembre 2009): 140–43. http://dx.doi.org/10.54386/jam.v11i2.1240.
Testo completoAbstract (sommario):
An experiment was conducted during rabi seasons of 2002-03 and 2003-04 to quantify the light interception and radiation use efficiency for three wheat varieties as affected by variable number of irrigations with the combination of three wheat varieties viz., HUW-234, HD-2285 and PBW-154. The light interception increased successively till 90 days after sowing (DAS) and thereafter a gradual decrease was observed till maturity of the crop. Four irrigations given at CRI, late tillering, late jointing and ear head formation stages showed highest radiation interception followed by three and two irrigations, however, the lowest radiation interception was observed for wheat crop receiving one irrigation only. On an average, 19.08 % and 12.79 % increase in radiation interception was found for wheat crop irrigated four and three times respectively as compared to singly irrigated crop. Highest radiation interception was recorded with HUW 234 followed by HD 2285 at all the growth stages except 15, 30, 45 DAS. More light interception reflected in significantly superior yield and yield attributes in the order of I4>I3>I2>I1. Subsequently, radiation useefficiency (RUE) also followed the similar trend showing highest and lowest RUE with four and one irrigation respectively. Among the different varieties, HUW-234 recorded highest radiation use efficiency followed by HD-2285. The average RUE during the entire growing period for HUW-234 and HD-2285 was found to be 1.68 g MJ-1 and 1.63 g MJ-1 respectively, which was 4.83 and 1.95 % higher than PBW-154.
4
J. S. BRAR, J. S. BAL e SOM PAL SINGH. "Radiant energy distribution in guava (Psidium guajava L.) plants at different spacings". Journal of Agrometeorology 11, n. 2 (1 dicembre 2009): 135–39. http://dx.doi.org/10.54386/jam.v11i2.1239.
Testo completoAbstract (sommario):
The study on radiant energy distribution in guava was carried out to optimize the planting density with respect to solar radiation interception by the plants to get higher yield of good quality fruits per unit area. The present investigations reveals that with increase in plant spacing from 6x2m to 6x4m the interception of radiation increased significantly during both rainy and winter crop seasons. However, it starts declining with further increase in plant spacing to 6x5m level. The interception of radiation remains somewhat static during the summer and rainy season months (May-September) and then starts decreasing with the advent of winter season upto April with sharp decline during the month of December to February. In the upper 1/3rd portion of plant canopy, more than 75% radiations were intercepted irrespective of plant spacing followed by 12-16% in middle and 6-9% in the lower 1/3rd parts of plant canopies. The plant spacing of 6x2m and 6x3m was found to be not encouraging owing to lower distribution of radiations particularly in middle and lower parts of plants. The plant spacing of 6x4m was found to be best due tomaximum absorption of solar radiation for higher fruiting of better quality fruits.
5
Olesen, Trevor, Stephen Morris e Lisa McFadyen. "Modelling the interception of photosynthetically active radiation by evergreen subtropical hedgerows". Australian Journal of Agricultural Research 58, n. 3 (2007): 215. http://dx.doi.org/10.1071/ar06110.
Testo completoAbstract (sommario):
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.
6
Heath, M. C., e P. D. Hebblethwaite. "Precision drilling combining peas (Pisum sativum L.) of contrasting leaf types at varying densities". Journal of Agricultural Science 108, n. 2 (aprile 1987): 425–30. http://dx.doi.org/10.1017/s0021859600079466.
Testo completoAbstract (sommario):
SummaryField experiments were conducted in 1983–4 to investigate the effect of precision drilling and plant density on establishment, growth, radiation interception and yield of combining peas of varying leaf phenotype (Varieties ‘Birte’, leafed; ‘Filby’, leafless; and ‘BS3’, semi-leafless). Precision drilling established a more uniform plant distribution than øyjord drilling; visual differences observed soon after emergence were not observed at flowering. Precision drilling resulted in more radiation interception early in the season for semi-leafless but not leafed peas; dry-matter production and photosynthetic area index (PAI) were not increased. Yield data indicated that precision drilling produced similar yields to øyjord drilling at similar densities. Increasing plant density increased radiation interception, dry-matter production and PAI during vegetative growth; density treatment effects were less marked post-flowering. Pea leaf phenotypes differed in their yield response to increasing density. Radiation interception was related to dry-matter production and PAI to obtain an estimate of photosynthetic efficiency (ε) and the attenuation coefficient (k), respectively, ε and k were constant irrespective of spatial arrangement, leaf phenotype and plant density. The relative importance of spatial arrangement and plant density in increasing radiation interception and PAI and influence on yield is discussed; other potential agronomic advantages of precision drilling are described.
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Cannell, M. G. R., R. Milne, L. J. Sheppard e M. H. Unsworth. "Radiation Interception and Productivity of Willow". Journal of Applied Ecology 24, n. 1 (aprile 1987): 261. http://dx.doi.org/10.2307/2403803.
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Zeng, Wenzhi, Yuchao Lu, Amit Kumar Srivastava, Thomas Gaiser e Jiesheng Huang. "Parameter Sensitivity and Uncertainty of Radiation Interception Models for Intercropping System". Ecological Chemistry and Engineering S 27, n. 3 (1 settembre 2020): 437–56. http://dx.doi.org/10.2478/eces-2020-0028.
Testo completoAbstract (sommario):
AbstractEstimating the interception of radiation is the first and crucial step for the prediction of production for intercropping systems. Determining the relative importance of radiation interception models to the specific outputs could assist in developing suitable model structures, which fit to the theory of light interception and promote model improvements. Assuming an intercropping system with a taller and a shorter crop, a variance-based global sensitivity analysis (EFAST) was applied to three radiation interception models (M1, M2 and M3). The sensitivity indices including main (Si) and total effects (STi) of the fraction of intercepted radiation by the taller (ftaller), the shorter (fshorter) and both intercrops together (fall) were quantified with different perturbations of the geometric arrangement of the crops (10-60 %). We found both ftaller and fshorter in M1 are most sensitive to the leaf area index of the taller crop (LAItaller). In M2, based on the main effects, the leaf area index of the shorter crop (LAIshorter) replaces LAItaller and becomes the most sensitive parameter for fshorter when the perturbations of widths of taller and shorter crops (Wtaller and Wshorter) become 40 % and larger. Furthermore, in M3, ftaller is most sensitive to LAItaller while fshorter is most sensitive to LAIshorter before the perturbations of geometry parameters becoming larger than 50 %. Meanwhile, LAItaller, LAIshorter, and Ktaller are the three most sensitive parameters for fall in all three models. From the results we conclude that M3 is the most plausible radiation interception model among the three models.
9
Bennett, J. M., T. R. Sinclair, Li Ma e K. J. Boote. "Single Leaf Carbon Exchange and Canopy Radiation Use Efficiency of Four Peanut Cultivars1". Peanut Science 20, n. 1 (1 gennaio 1993): 1–5. http://dx.doi.org/10.3146/i0095-3679-20-1-1.
Testo completoAbstract (sommario):
Abstract Knowledge of the interception of solar radiation by crop canopies and the use of that radiation for carbon assimilation is essential for understanding crop growth and yield as a function of the environment. A field experiment was conducted in 1990 at Gainesville, FL to determine if differences in single leaf carbon exchange rate (CER), canopy radiation interception, radiation use efficiency (g dry matter produced per unit of solar radiation intercepted), and increase in seed harvest index with time exist among several commonly grown peanut (Arachis hypogaea L.) cultivars. Four cultivars (Early Bunch, Florunner, Marc I, and Southern Runner) were grown in field plots on a Kendrick fine sand (a loamy, siliceous, hyperthermic Arenic Paleudult) under fully irrigated, intensive management. Total crop and seed dry matter accumulation were determined, and canopy radiation interception measured at weekly intervals. CER of uppermost, fully expanded sunlit leaves were determined at midday at 2-wk intervals. Single leaf CER's were similar among cultivars (25 to 35 μmol CO2 m-2 s-1) and relatively stable throughout most of the season, before declining during late seed filling. Although interception of radiation differed somewhat among cultivars during early canopy development, total crop dry matter accumulation was linearly related to the cumulative amount of radiation intercepted by all four cultivars (r2=≥0.99). Radiation use efficiency was similar among all cultivars with a mean of 1.00 g dry matter accumulated per MJ of intercepted solar radiation. The increase in seed harvest index with time was linear (r2≤0.94) and the rates of increase were similar among the Early Bunch, Florunner, and Marc I cultivars (0.0058 d-1), but lower (0.0043 d-1) for the later maturing Southern Runner cultivar. Results from this study indicated that the primary differences among these four cultivars were in early-season development of the leaf canopy and resultant radiation interception and the rate of seed growth, rather than the capacity to assimilate carbon dioxide.
10
Connor, David J., Ana Centeno e María Gómez-del-Campo. "Yield determination in olive hedgerow orchards. II. Analysis of radiation and fruiting profiles". Crop and Pasture Science 60, n. 5 (2009): 443. http://dx.doi.org/10.1071/cp08253.
Testo completoAbstract (sommario):
Profiles of fruit density, fruit size, and oil content were measured on 12 occasions in 7 olive orchards in Spain and 2 in Australia. Orchard structure varied widely. Height ranged from 2.0 to 5.5 m, row spacing from 3 to 6 m, and canopy width from 0.7 to 3 m. Most orchards were oriented north–south (N–S) but one in Spain was oriented close to east–west (E–W) (20° NE–SW). All orchards in Spain were cv. Arbequina, and in Australia they were cvv. Barnea and Picual. Analyses with a model of interception and transmission that estimated interception by individual sides of hedgerows revealed that fruit size and oil content were strongly related to intercepted radiation during the month before harvest across all orchards. Relationships were also evident between fruit density and interception but varied among orchards and years, indicating the importance of other environmental and probably physiological effects. In N–S orchards of cv. Arbequina, average fruit size and oil content increased linearly from 0.40 g (dry weight) to 0.72 g, and from 36 to 49% (of dry weight), as daily intercepted PAR increased from 6 to 25 mol/m2 (15–60% of horizontally incident radiation). The general principles of response extended to E–W orchards. There, it was shown that generally large fruit with high oil content on S sides was consistent with the plateau responses to radiation evident in the more extensive N–S data. On the N side, however, and accounting for transmission through the hedgerow, both fruit size and oil content were greater than in positions intercepting equivalent radiation in N–S orchards. Examples are provided of the utility of responses of fruit density, size, and oil content in establishing combinations of row height, row width, and row distance to improve or maintain productivity in some of the orchards included in the study.
11
Li, Lin, Rosalind A. Bueckert, Yantai Gan e Tom Warkentin. "Light interception and radiation use efficiency of fern- and unifoliate-leaf chickpea cultivars". Canadian Journal of Plant Science 88, n. 6 (1 novembre 2008): 1025–34. http://dx.doi.org/10.4141/cjps07056.
Testo completoAbstract (sommario):
A chickpea (Cicer arietinum L.) crop with rapid leaf development, high solar radiation interception, and efficient use of radiation can maximize the yield potential in a short-season typical of the Northern Great Plains. This study determined the effects of cultivars varying in leaf architecture on light interception (LI) and radiation use efficiency (RUE) in chickpea. Six kabuli chickpea cultivars with fern and unifoliate-leaf traits were grown under low (45 plants m-2) and high (85 plants m-2) population density at Saskatoon and Swift Current, Saskatchewan, in 2003 and 2004. Fern-leaf cultivars achieved consistently higher maximum LI, and greater cumulative intercepted radiation than cultivars with the unifoliate-leaf. Estimated RUE varied largely with growing season, but did not differ among cultivars or between plant populations. Compared with low plant population, high plant population resulted in greater maximum LI in only 1 out of 4 location-years, but higher cumulative intercepted radiation in 3 out of 4 location-years. Our results indicated that future high-yielding kabuli chickpea cultivars for short seasons will benefit from increased canopy LI and seasonal cumulative intercepted radiation via the fern-leaf trait, although the fern-leaf does not further increase RUE. Use of fern-leaf cultivars, coupled with adoption of strategies that promote a rapid canopy development and improved radiation interception are keys to maximizing chickpea yield potential in the short-seasons experienced in the Northern Great Plains. Key words: Cicer arietinum, pinnate fern-leaf, unifoliate, plant population, canopy, radiation interception
12
Zhu, Binglin, Fusang Liu, Ziwen Xie, Yan Guo, Baoguo Li e Yuntao Ma. "Quantification of light interception within image-based 3-D reconstruction of sole and intercropped canopies over the entire growth season". Annals of Botany 126, n. 4 (17 marzo 2020): 701–12. http://dx.doi.org/10.1093/aob/mcaa046.
Testo completoAbstract (sommario):
Abstract Background and Aims Light interception is closely related to canopy architecture. Few studies based on multi-view photography have been conducted in a field environment, particularly studies that link 3-D plant architecture with a radiation model to quantify the dynamic canopy light interception. In this study, we combined realistic 3-D plant architecture with a radiation model to quantify and evaluate the effect of differences in planting patterns and row orientations on canopy light interception. Methods The 3-D architectures of maize and soybean plants were reconstructed for sole crops and intercrops based on multi-view images obtained at five growth dates in the field. We evaluated the accuracy of the calculated leaf length, maximum leaf width, plant height and leaf area according to the measured data. The light distribution within the 3-D plant canopy was calculated with a 3-D radiation model. Finally, we evaluated canopy light interception in different row orientations. Key Results There was good agreement between the measured and calculated phenotypic traits, with an R2 >0.97. The light distribution was more uniform for intercropped maize and more concentrated for sole maize. At the maize silking stage, 85 % of radiation was intercepted by approx. 55 % of the upper canopy region for maize and by approx. 33 % of the upper canopy region for soybean. There was no significant difference in daily light interception between the different row orientations for the entire intercropping and sole systems. However, for intercropped maize, near east–west orientations showed approx. 19 % higher daily light interception than near south–north orientations. For intercropped soybean, daily light interception showed the opposite trend. It was approx. 49 % higher for near south–north orientations than for near east–west orientations. Conclusions The accurate reconstruction of 3-D plants grown in the field based on multi-view images provides the possibility for high-throughput 3-D phenotyping in the field and allows a better understanding of the relationship between canopy architecture and the light environment.
13
Wallace, J. S. "Evaporation and radiation interception by neighbouring plants". Quarterly Journal of the Royal Meteorological Society 123, n. 543 (ottobre 1997): 1885–905. http://dx.doi.org/10.1002/qj.49712354306.
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Goyne, PJ, SP Milroy, JM Lilley e JM Hare. "Radiation interception, radiation use efficiency and growth of barley cultivars". Australian Journal of Agricultural Research 44, n. 6 (1993): 1351. http://dx.doi.org/10.1071/ar9931351.
Testo completoAbstract (sommario):
Dry matter production and utilization of photosynthetically active radiation (PAR) was studied for barley (Hordeurn vulgare L.) in the field at Hermitage Research Station, Qld. In 1990, four cultivars (Gilbert, Tallon, Grimmett, Skiff) were sown at three times and grown with non-limiting soil moisture. In 1991, soil moisture limitations were imposed on one sowing of the cultivar Grimmett. The radiation extinction coefficient (k) was 0.41�0.02 and did not vary with cultivar, time of sowing or soil moisture availability. Radiation use efficiency (RUE) (based on absorbed PAR and above-ground dry matter) did not change with time of sowing but did vary between cultivars. RUE was highest for Gilbert (2.90�0.10 g MJ-1), while the other three cultivars averaged 2.60�0.04 g MJ-l. RUE of Grimmett was significantly lower in 1991 (1.48�0.07 g MJ-1) than in 1990 (2.60�0.07g MJ-1), but soil moisture differences in 1991 did not significantly affect RUE. Several factors with possible links with RUE were examined and discussed. Of the variables examined those which showed the strongest relationships with RUE were average daily vapour pressure deficit and average daily minimum temperature.
15
Bélanger, G., e J. E. Richards. "Growth analysis of timothy cultivars differing in maturity". Canadian Journal of Plant Science 75, n. 3 (1 luglio 1995): 643–48. http://dx.doi.org/10.4141/cjps95-109.
Testo completoAbstract (sommario):
The delay in ear emergence or heading between early and late-maturing timothy (Phleum pratense L.) cultivars can be up to 3 wk. The objective of this study was to determine the relative importance of radiation interception and radiation-use efficiency in the differences in shoot growth between early and late-maturing timothy cultivars. During the primary growth in 1991 and 1992, four timothy cultivars differing in maturity were compared for shoot growth, leaf area development, radiation interception and radiation-use efficiency using weekly samplings. Stem elongation of early-maturing cultivars progressed faster than that of late-maturing cultivars. Early-maturing cultivars had greater shoot growth and RUE than late-maturing cultivars. Differences in cumulative intercepted PAR among cultivars were relatively small compared with cultivar differences in RUE. Hence, the greater shoot growth of early-maturing cultivars compared with that of late-maturing cultivars was attributed to a greater RUE of the early-maturing cultivars. Consequently, different values of RUE should be used for early and late-maturing timothy cultivars in crop models based on efficiencies of radiation interception and utilization. Key words:Phleum pratense L., cultivars, growth, radiation, photosynthesis
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Yoon, Hyo In, Hyun Young Kim, Jaewoo Kim, Myung-Min Oh e Jung Eek Son. "Quantitative Analysis of UV-B Radiation Interception in 3D Plant Structures and Intraindividual Distribution of Phenolic Contents". International Journal of Molecular Sciences 22, n. 5 (7 marzo 2021): 2701. http://dx.doi.org/10.3390/ijms22052701.
Testo completoAbstract (sommario):
Ultraviolet-B (UV-B) acts as a regulatory stimulus, inducing the dose-dependent biosynthesis of phenolic compounds such as flavonoids at the leaf level. However, the heterogeneity of biosynthesis activation generated within a whole plant is not fully understood until now and cannot be interpreted without quantification of UV-B radiation interception. In this study, we analyzed the spatial UV-B radiation interception of kales (Brassica oleracea L. var. Acephala) grown under supplemental UV-B LED using ray-tracing simulation with 3-dimension-scanned models and leaf optical properties. The UV-B-induced phenolic compounds and flavonoids accumulated more, with higher UV-B interception and younger leaves. To distinguish the effects of UV-B energy and leaf developmental age, the contents were regressed separately and simultaneously. The effect of intercepted UV-B on flavonoid content was 4.9-fold that of leaf age, but the effects on phenolic compound biosynthesis were similar. This study confirmed the feasibility and relevance of UV-B radiation interception analysis and paves the way to explore the physical and physiological base determining the intraindividual distribution of phenolic compound in controlled environments.
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Villa, Bruna de, Mirta Teresinha Petry, Maicon Sérgio Nascimento dos Santos, Juliano Dalcin Martins, Isabel Lago, Murilo Brum de Moura, Henrique Schaf Eggers et al. "Effects of Minimum and Maximum Limits of Solar Radiation and Its Temporal and Geographic Interactions". Journal of Agricultural Science 14, n. 8 (15 luglio 2022): 173. http://dx.doi.org/10.5539/jas.v14n8p173.
Testo completoAbstract (sommario):
In order to achieve high yields, the use of radiation by agricultural crops must be improved in order to maximize and extend the duration of foliar interception of solar radiation. Appropriately, studies aimed at the understanding and behavior of radiation in plants are extremely relevant. Accordingly, the objective of this study was to approach information about the concepts, radiation availability temporal, geographical, photosynthesis efficiency as a function of leaf arrangement and radiation interception efficiency × leaf area index (LAI). Studies aimed at a significant comprehension of radiation in crops demonstrate that the plant growth and development depend on the intensity and duration of solar radiation. More surveys are required on the subject for a better development of the culture, aiming to guarantee that the plants have better conditions to express their potential.
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Fochesatto, Elizandro, Astor Henrique Nied, Homero Bergamaschi, Genei Antonio Dalmago, Daniele Gutterres Pinto, Samuel Kovaleski, Gilberto Roca da Cunha e Jorge Alberto Gouvea. "Interception of solar radiation by the productive structures of spring canola hybrids". Ciência Rural 46, n. 10 (7 luglio 2016): 1790–96. http://dx.doi.org/10.1590/0103-8478cr20151571.
Testo completoAbstract (sommario):
ABSTRACT: The objective of this study was to adjust parameters related to the interception of photosynthetically active radiation (PAR) by reproductive structures of spring canola, with different nitrogen levels and hybrids. Two field experiments were conducted, being one with different sowing dates and hybrids (Hyola 61 and Hyola 432) and another with doses of 10, 20, 40, 80, 160kg ha-1 of N, applied in top dressing. They were conducted in Passo Fundo and Coxilha, RS, Brazil, in 2011 and 2014, respectively.The evaluated variables were: area index of reproductive structures, interception efficiency and extinction coefficient of these structures for PAR. PAR interception increased by increasing the reproductive structures volume. Interception efficiency of PAR by reproductive structures ranged from 45 to 80%. It was higher in the Hyola 61 hybrid and at the highest dose of N. The extinction coefficient of reproductive structures for PAR was 0.44 in non-limiting doses of N.
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Dong, Liming, Yuchao Lu, Guoqing Lei, Jiesheng Huang e Wenzhi Zeng. "Improve the Simulation of Radiation Interception and Distribution of the Strip-Intercropping System by Considering the Geometric Light Transmission". Agronomy 14, n. 1 (22 gennaio 2024): 227. http://dx.doi.org/10.3390/agronomy14010227.
Testo completoAbstract (sommario):
Intercropping radiation interception model is a promising tool for quantifying solar energy utilization in the intercropping system. However, few models have been proposed that can simulate intercropping radiation interception accurately and with simplicity. This study proposed a new statistical model (DRT model), which enables the simulation of daily radiation distribution by considering the geometric light transmission in the intercropping system. To evaluate model performance, the radiation interception and distribution in two wheat/maize strip intercropping experiments (A and B) were simulated with the DRT model and other two statistical models, including the horizontal homogeneous canopy model (HHC model) and the Gou Fang model (GF model). Experiment A was conducted in different intercropping configurations, while Experiment B was conducted in soils with different salinity levels. In both experiments, the HHC model exhibited the poorest performance (0.120 < RMSE < 0.172), while the DRT model obtained a higher simulation accuracy in the fraction of photosynthetically active radiation (PAR) interception, with RMSE lower by 0.008–0.022 and 0.022–0.125 than the GF and the HHC models, respectively. Especially, the DRT model showed stronger stability than the other two models under soil salinity stress, with R2 higher by 0.129–0.354 and RMSE lower by 0.011–0.094. Moreover, the DRT model demonstrated a relatively ideal simulation of the daily radiation distribution in Experiment A (0.840 < R2 < 0.893, 0.105 < RMSE < 0.140) and Experiment B (0.683 < R2 < 0.772, 0.111 < RMSE < 0.143), especially when the continuous canopy formed during the later crop growth stages. These results indicate the superiority of the DRT model and could improve our understanding of radiation utilization in the intercropping system.
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Bauerle, William L., e Joseph D. Bowden. "A Fiberoptic-based System for Integrating Photosynthetically Active Radiation in Plant Canopies". HortScience 39, n. 5 (agosto 2004): 1027–29. http://dx.doi.org/10.21273/hortsci.39.5.1027.
Testo completoAbstract (sommario):
This report describes a system for integrating photosynthetically active radiation (PAR) using fiberoptics. Many photoelectric sensors or 1-m-long line sensors that integrate individual interception points for spatial averaging were replaced with fiberoptics, which integrate interception points. Depending on the positioning of optical fibers and the amount of fibers terminated at a PAR sensor, whole-plant, canopy layer, and individual leaf light interception can be determined. The use of fiberoptics has the added advantage of being very small in comparison to the bulk of a typical quantum sensor. The fiberoptic-based system potentially is a more accurate, less expensive method to integrate PAR throughout plant canopies than PAR sensors.
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T, Govindaraj, N. Maragatham, S. P. Ramanathan, V. Geethalakshmi e M. K. Kalarani. "Light interception and radiation use efficiency (RUE) in maize (Zea mays. L) intercropping with greengram (Vigna radiata L.)". Journal of Applied and Natural Science 15, n. 3 (19 settembre 2023): 1044–50. http://dx.doi.org/10.31018/jans.v15i3.4751.
Testo completoAbstract (sommario):
Intercropping is growing two or more crop species simultaneously, different canopy architectures by row configuration, changing light interception, radiation utilisation, and increased yield. The present study aimed to evaluate different intercropping systems affected light interception per cent and radiation use efficiency in maize (Zea mays L.) intercropping with greengram (Vigna radiata L.) different ratios. Field experiments were conducted for Kharif 2022 and Rabi 2022-2023 seasons, which were laid out in a split-plot design and replicated three times. Three Nitrogen levels viz., N1 - 75 % RDN (Recommended dose of Nitrogen), N2 – 100% RDN, N3-125% RDN had taken as the main plot and three intercropping treatments were taken as subplot viz., M2G2- replacement series (two row of maize and two row of Greengram), M4G2- replacement series (four rows of maize and two row of Greengram), M2G3-paired row system (two rows of maize and three rows of Greengram), and sole maize. Both light interception and radiation use efficiency were significantly affected by intercropping systems. Light interception per cent of the main crop (maize) was significantly higher (69.0, 75.5 and 71.0 % during Kharif and 60.1, 78.1 and 76.6 during rabi) at vegetative, flowering and maturity phases, respectively. The Kharif 2022 and Rabi 2022-2023 maximum Radiation Use Efficiency (RUE) of Maize intercropping with green gram (maize + greengram) was higher in T12 (M2G3 paired row with 125 % Recommended Dose of Nitrogen) recorded as 2.46 (Kharif) and 1.43 (rabi). The outcome might be utilised to optimise the row configuration of intercropping design, explain the mechanism of intercropping on light utilisation, and improve radiation use efficiency.
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Mahakosee, Supattra, Sanun Jogloy, Nimitr Vorasoot, Piyada Theerakulpisut, Banyong Toomsan, Carl Corley Holbrook, Craig K. Kvien e Poramate Banterng. "Light Interception and Radiation Use Efficiency of Three Cassava Genotypes with Different Plant Types and Seasonal Variations". Agronomy 12, n. 11 (18 novembre 2022): 2888. http://dx.doi.org/10.3390/agronomy12112888.
Testo completoAbstract (sommario):
The yield potential of cassava might be increased by enhancing light interception and the ability to convert energy into biomass and yield, which is described as radiation use efficiency (RUE). The objective of this study was to determine light interception, extinction coefficient (k), and RUE of three cassava genotypes (Kasetsart 50 (KU50), Rayong 11 (RY11), and CMR38-125-77) under seasonal variations. The field experiments were conducted in a randomized complete block design with four replications, using two planting dates for 2 years at Khon Kaen, Thailand. Data were recorded for weather conditions, light interception, leaf area index (LAI), and biomass. Solar radiation interception, RUE, and k were calculated. Light interception of the crop planted in May sharply increased in the early growth stage, whereas the crop planted in November slowly increased and could maintain higher light interception from the mid–late growth stages. Light interception and LAI had a moderate to high coefficient of determination (R2 = 0.61–0.89) for three cassava genotypes and all planting dates. The k values ranged from 0.59 to 0.94, varying by genotypes and planting dates, indicating that the leaf orientation of the three cassava genotypes was horizontally oriented. The relationship between biomass accumulation and cumulative solar radiation produced a high value of R2 (0.86–0.99). The RUE for biomass (RUEbi) varied by genotype and planting date, ranging from 0.66 g MJ−1 to 0.97 g MJ−1. However, the RUE for storage root dry weight (RUEsr) ranged from 0.29 g MJ−1 to 0.66 g MJ−1. The RUEbi and RUEsr in each genotype on each planting date were significantly different. The highest RUEbi and RUEsr were found at 4–6 and 7–9 MAP for almost all genotypes and planting dates, except for the crop planted in November 2015, when both RY11 and CMR38-125-77 had the highest RUEbi at 10–12 MAP. RY11 had a lower LAI compared to other genotypes, which contributed to lower light disruption and lower RUEbi and RUEsr. KU50 and CMR38-125-77 could maintain canopy light interception during canopy development and storage root accumulation stages and had high RUEbi and RUEsr, resulting in high biomass and crop yield.
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., Lanuakum, Graceli I. Yepthomi e C. S. Maiti. "Effect of Radiation Interception and Canopy Temperature on Growth, Yield and Quality in Banana Cv. Grande Naine (AAA) under Different Planting Densities". Journal of Horticultural Sciences 10, n. 2 (31 dicembre 2015): 172–76. http://dx.doi.org/10.24154/jhs.v10i2.125.
Testo completoAbstract (sommario):
A study was made to test the effect of radiation interception and canopy temperature under different planting densities [T1- 1.5m x 1.5m (4,444 plants/ha); T2- 2m x 2m (2500 plants/ha); T3- 1.5m x 2.5m (2666 plants/ha); T4- 2m x 2.5m (2000 plants/ha); T5- 2.5m x 2.5m (1600 plants/ha)] on growth, yield and quality in banana cv. Grande Naine. With an increase in planting density, plant height increased significantly. Pseudostem was tallest in the closest spacing, viz., 1.5m x 1.5m (T1), and was shortest in the widest spacing, 2.5m x 2.5m (T5). T1 treatment (1.5m x 1.5m) recorded the least average-canopy-temperature (25.80°C/day) from the flowering to the harvest. T5 recorded the maximum average-radiation-interception, with a value of 432.16 lux/8 hr/day; whereas, T1 recorded minimum average-radiation-interception of 219.58 lux/8 hr/day. Significant influence of spacing was seen on yield /ha. Plants grown under higher density yielded comparatively higher yield (82.65 t/ha) under a spacing of 1.5m x 1.5m (T1). It is thus seen that growth parameters (pseudostem height and number of leaves) and yield/ha in banana was superior at a higher density (1.5m x 1.5m); whereas, in terms of quality of fruit (TSS and total sugar content) spacing of 2.5m x 2.5m was superior. This indicates a positive influence of radiation interception and canopy temperature in banana production.
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Lampinen, Bruce D., Vasu Udompetaikul, Gregory T. Browne, Samuel G. Metcalf, William L. Stewart, Loreto Contador, Claudia Negrón e Shrini K. Upadhyaya. "A Mobile Platform for Measuring Canopy Photosynthetically Active Radiation Interception in Orchard Systems". HortTechnology 22, n. 2 (aprile 2012): 237–44. http://dx.doi.org/10.21273/horttech.22.2.237.
Testo completoAbstract (sommario):
A mobile platform was developed for measuring midday canopy photosynthetically active radiation (PAR) interception in orchards. The results presented are for almond (Prunus dulcis) and walnut (Juglans regia), but the mobile platform can be used in other orchard crops as well. The mobile platform is adjustable to accommodate orchard row spacing from 4.8 to 7.8 m and is equipped with a global positioning satellite (GPS) receiver and radar for positional assessment as well as three IR thermometers for measuring soil surface temperature. Data from the mobile platform are logged at 10 Hz and stored on a data logger. Custom software has been developed to process the data. The mobile platform was used extensively for mapping midday canopy PAR interception in almond and walnut orchards in 2009 and 2010. The mobile platform produced comparable results to those collected with a handheld light bar with the advantage of being able to cover much larger areas and compare these data to mechanically harvested yield data over the same area. For almond orchards, midday canopy PAR interception peaked at ≈70% at an orchard age of ≈12 years. For walnut orchards, midday canopy PAR interception continued to increase to ≈15 years of age and peaked at a level above 80%. The mobile platform was also able to follow seasonal development of midday canopy PAR interception in young and mature orchards. This technology has potential for evaluating new varieties in terms of productivity per unit PAR intercepted, in evaluating hand pruning or mechanical hedging practices in terms of impact on PAR interception/productivity as well as evaluating effectiveness of insect or disease management treatments. It also has potential as a reference point for grower self-assessment to evaluate orchard canopy development compared with other orchards of similar variety, spacing, etc. Finally, this technology could be used as ground truth referencing for remotely sensed data.
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Gong, Hong Wei, Zhong Yuan Wang, Xuan Yan e Huan Fu. "Theory of Solar Hot Water System Construction Application Engineering Evaluation Field Test Method - The Amount of Solar Irradiance Intercept Method". Applied Mechanics and Materials 737 (marzo 2015): 71–75. http://dx.doi.org/10.4028/www.scientific.net/amm.737.71.
Testo completoAbstract (sommario):
In the energy efficiency evaluation of renewable energy, in order to confirm the application of solar hot water system of building practical application effect, on-site testing is needed for solar water heating system. During the short term test, in order to improve the testing progress and to reduce the input, the relevant standard proposes the "solar radiation interception method". This paper mainly contrasts and analyzes the results deviation of "solar radiation interception method" in the actual test application. It also improveds the testing methods and testing precision.
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Groot, Arthur. "Biases in LI-COR Plant Canopy Analyzer estimates of seasonal light interception by black spruce and trembling aspen canopies". Canadian Journal of Forest Research 35, n. 11 (1 novembre 2005): 2664–70. http://dx.doi.org/10.1139/x05-184.
Testo completoAbstract (sommario):
This article examines four sources of bias in the estimation of seasonal light interception by black spruce (Picea mariana (Mill.) BSP) and trembling aspen (Populus tremuloides Michx.) canopies using the LI-COR LAI-2000 Plant Canopy Analyzer: (i) geometric averaging of gap fractions, (ii) unrepresentative elevation angle intervals for radiation detectors, (iii) assumption of isotropic radiance distribution, and (iv) inclusion of light intercepted by stems in the estimate of canopy light interception. Bias source i caused overestimates of canopy light interception, source ii caused underestimates, source iii caused little bias, and source iv caused overestimates. The magnitude of bias from sources i, ii, and iv increased as fractional light interception by canopies decreased. The average bias in seasonal light interception for all sources combined was 5% for black spruce canopies and 17% for trembling aspen canopies. It is recommended that canopy light interception and understorey light level estimates be calculated in a way to reduce bias from sources i and ii. For estimates of canopy interception alone, bias from source iv should also be reduced.
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Daniells, J. W. "MEASUREMENT OF SOLAR RADIATION INTERCEPTION BY TREE CROPS". Acta Horticulturae, n. 175 (marzo 1986): 255–56. http://dx.doi.org/10.17660/actahortic.1986.175.37.
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Díaz-Espejo, A., J. E. Fernández, P. J. Durán, I. F. Girón, H. Sinoquet, G. Sonohat, J. Phattaralerphong et al. "CANOPY ARCHITECTURE AND RADIATION INTERCEPTION MEASUREMENTS IN OLIVE". Acta Horticulturae, n. 791 (giugno 2008): 531–38. http://dx.doi.org/10.17660/actahortic.2008.791.82.
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Whelan, H. G., e R. E. Gaunt. "Disease effects on radiation interception in barley crops". Proceedings of the New Zealand Weed and Pest Control Conference 42 (8 gennaio 1989): 217–20. http://dx.doi.org/10.30843/nzpp.1989.42.10955.
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Manrique, L. A., J. R. Kinry, T. Hodges e D. S. Axness. "Dry Matter Production and Radiation Interception of Potato". Crop Science 31, n. 4 (luglio 1991): 1044–49. http://dx.doi.org/10.2135/cropsci1991.0011183x003100040040x.
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Pang, Ce, Gan-lin Shan, Wei-ning Ma e Gong-guo Xu. "Sensor radiation interception risk control in target tracking". Defence Technology 16, n. 3 (giugno 2020): 695–704. http://dx.doi.org/10.1016/j.dt.2019.10.014.
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Zhang, Yingyu, Juan Yang, Marinus van Haaften, Linyi Li, Shenglian Lu, Weiliang Wen, Xiuguo Zheng, Jian Pan e Tingting Qian. "Interactions between Diffuse Light and Cucumber (Cucumis sativus L.) Canopy Structure, Simulations of Light Interception in Virtual Canopies". Agronomy 12, n. 3 (28 febbraio 2022): 602. http://dx.doi.org/10.3390/agronomy12030602.
Testo completoAbstract (sommario):
Plant photosynthesis and biomass production are associated with the amount of intercepted light, especially the light distribution inside the canopy. Three virtual canopies (n = 80, 3.25 plants/m2) were constructed based on average leaf size of the digitized plant structures: ‘small leaf’ (98.1 cm2), ‘medium leaf’ (163.0 cm2) and ‘big leaf’ (241.6 cm2). The ratios of diffuse light were set in three gradients (27.8%, 48.7%, 89.6%). The simulations of light interception were conducted under different ratios of diffuse light, before and after the normalization of incident radiation. With 226.1% more diffuse light, the result of light interception could increase by 34.4%. However, the 56.8% of reduced radiation caused by the increased proportion of diffuse light inhibited the advantage of diffuse light in terms of a 26.8% reduction in light interception. The big-leaf canopy had more mutual shading effects, but its larger leaf area intercepted 56.2% more light than the small-leaf canopy under the same light conditions. The small-leaf canopy showed higher efficiency in light penetration and higher light interception per unit of leaf area. The study implied the 3D structural model, an effective tool for quantitative analysis of the interaction between light and plant canopy structure.
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Pan, Yonghui, Shuai Gao, Kailiu Xie, Zhifeng Lu, Xusheng Meng, Shiyu Wang, Jianwei Lu e Shiwei Guo. "Higher Radiation Use Efficiency Produces Greater Biomass Before Heading and Grain Yield in Super Hybrid Rice". Agronomy 10, n. 2 (2 febbraio 2020): 209. http://dx.doi.org/10.3390/agronomy10020209.
Testo completoAbstract (sommario):
To reveal the physiological mechanism underlying the yield advantage of super hybrid rice compared with inbred super rice, a super hybrid rice cultivar Yliangyou 3218 (YLY) and an inbred super rice cultivar Zhendao 11 (ZD) were field grown under five nitrogen (N) fertilizer rates in 2016 and 2017. The average grain yield of YLY across nitrogen fertilizer rates was 10.1 t ha−1 in 2016 and 9.7 t ha−1 in 2017, 29.6% and 21.3% higher than that of ZD in 2016 and 2017, respectively. YLY showed higher above-ground biomass accumulation, especially growth before heading, which was mainly due to its faster green leaf area index (GLAI) formation and greater maximum GLAI (GLAImax). The daily radiation interception (RIdaily) was 15.0% higher in YLY than ZD, but the accumulated radiation interception (RIacc) before heading showed little difference between them because ZD had a longer growth duration. The radiation use efficiency (RUE) of YLY before heading was 54.7% higher than that of ZD (YLY, 2.12 g MJ−1; ZD, 1.37 g MJ−1). Our result demonstrated that the yield advantage of YLY was due to its higher above-ground biomass before heading, which was mainly achieved by its improvement in RUE rather than radiation interception.
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Al-hazmi, Manea H., Alan N. Lakso e Steven S. Denning. "EFFECTS OF TRELLIS FORM ON RADIATION INTERCEPTION WATER USE AND PHOTOSYNTHESIS IN GRAPEVINES". HortScience 28, n. 5 (maggio 1993): 570c—570. http://dx.doi.org/10.21273/hortsci.28.5.570c.
Testo completoAbstract (sommario):
Manipulating radiation interception by using horizontal and vertical trellis forms was tested for effects on water loss and photosynthesis on sunny days. Water loss from 15 potted Pinot Noir vines of each form was estimated by weighing the vines at two hour intervals during the day. Radiation interception for vines and gas exchange of individual exposed leaves was measured over the day to evaluate the leaf activity patterns in relation to exposure patterns. Similarly, diurnal whole vine photosynthesis measurements were taken by using clear plastic “balloon” whole vine chambers. The horizontal form had higher radiation interception than the vertical form during the day, resulting in higher water loss from the horizontal form. Under N-S orientation, the horizontal form showed a gradual decrease in exposed leaf and whole vine photosynthesis starting in late-morning while the vertical form had a more uniform pattern over the day. The long periods of leaf exposure of horizontal canopies appears to induce a photosynthetic decline that also reduces afternoon transpiration. Vertical forms have two populations of leaves that are exposed for shorter periods, thus less photosynthetic decline occurs. Vertical trellis forms may have potential for improving water use efficiencies in arid regions with high radiation.
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McCrady, R. L., e E. J. Jokela. "Canopy Dynamics, Light Interception, and Radiation Use Efficiency of Selected Loblolly Pine Families". Forest Science 44, n. 1 (1 febbraio 1998): 64–72. http://dx.doi.org/10.1093/forestscience/44.1.64.
Testo completoAbstract (sommario):
Abstract Needlefall, aboveground net primary production (ANPP), canopy light interception and attenuation, and "radiation use efficiency" of five open-pollinated loblolly pine (Pinus taeda L.) families were investigated using 100-tree family block plots near Summerville, SC. Family variation in annual needlefall amounts was significant during the fourth (from 4796 to 6191 kg ha-1) and fifth growing seasons (from 4717 to 5721 kg ha-1); needlefall patterns for the poorest performing family were asynchronous from those of the others, with notably higher needlefall rates from April to July. Estimates of ANPP at age 4 yr varied by 16% (from 32.9 to 38.2 Mg ha-1) among families, and were generally commensurate with progeny test rankings based on height growth. The relationship between ANPP and leaf area index (LAI) was both significant and curvilinear, with an apparent optimum level of production (42.6 Mg ha-1) achieved at a LAI of about 13 (all-sided; February). The least productive families had the lowest mean LAI (e.g., 7.9), while the most productive families generally had higher levels of LAI (e.g., 13.6). Significant family differences in canopy light interception were present in every month sampled except June, when photosynthetically active radiation (PAR) interception exceeded 90% for all families. Light extinction coefficients (k) for February differed significantly among the five families, and ranged from 0.28 to 0.38; families with the largest LAIs generally had the lowest values of k and the highest levels of PAR interception. A strong linear relationship (r² = 0.74) was found between ANPP and intercepted PAR. Estimates of the dry matter:radiation quotient (ε "radiation use efficiency") differed significantly among families, and ranged from 1.33 g MJ-1 to 1.48 g MJ-1. Results of this study suggest that fundamental differences exist in production ecology among loblolly pine families, and that canopy-level characteristics such as LAI, PAR interception, and "radiation use efficiency" are important in conferring differential family performance. For. Sci. 44(1):64-72.
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Hughes, G., J. D. H. Keatinge, P. J. M. Cooper e N. F. Dee. "Solar radiation interception and utilization by chickpea (Cicer arietinum L.) crops in northern Syria". Journal of Agricultural Science 108, n. 2 (aprile 1987): 419–24. http://dx.doi.org/10.1017/s0021859600079454.
Testo completoAbstract (sommario):
SummaryAn analysis of chickpea experiments carried out in northern Syria during the 1980–1 and 1981–2 growing seasons showed that both intercepted solar radiation and its rate of conversion to dry matter were variable components of dry-matter production. Among the sources of variation in the experiments, the most important factor affecting both interception and utilization of solar radiation was site. Winter planting also led to increased solar radiation interception and utilization. Used in conjunction with chickpea lines resistant to blight, winter planting seems likely to lead to increased productivity. In higher rainfall areas, where the crop is usually grown, such an increase would be of commercial significance. In drier areas, winter planting would enable the cultivation of chickpea as a subsistence crop.
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Ohashi, Yuta, Misato Murai, Yasuhiro Ishigami e Eiji Goto. "Light-Intercepting Characteristics and Growth of Tomatoes Cultivated in a Greenhouse Using a Movable Bench System". Horticulturae 8, n. 1 (9 gennaio 2022): 60. http://dx.doi.org/10.3390/horticulturae8010060.
Testo completoAbstract (sommario):
The objective of this study was to investigate the growth and light-intercepting characteristics of tomatoes when movable benches are used in their cultivation. We cultivated tomatoes in a greenhouse (168 m2) during summer (9 July–9 September 2018) under different furrow distances (F1.0 = 1.0 m and F1.6 = 1.6 m) and movable benches (M indicates that the furrow distance = 0.4–0.8 m). Compared to the other treatments, when the movable bench was used to the change furrow distance depending on the plant growth stage (M treatment), the percentage of canopy light interception increased to ~90% at the early stage of plant growth (~20 days after transplanting). The percentage of canopy light interception for different treatments increased in the order of M > F1.0 > F1.6, and it increased towards the end of cultivation. In addition, the yield per unit area exhibited the same trend. Therefore, the solar radiation inside a greenhouse can be efficiently intercepted by plants when movable benches are used. This indicated that it was possible to increase plant yield per unit area using movable benches in plant cultivation.
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Wu, Zijian, Fei Wang e Jianjiang Zhou. "Netted Radar Tracking with Multiple Simultaneous Transmissions against Combined PDS Interception". Journal of Sensors 2020 (4 gennaio 2020): 1–12. http://dx.doi.org/10.1155/2020/5932539.
Testo completoAbstract (sommario):
One of the advantages of a netted airborne radar system (NARS) is escaping interception of the passive detection system (PDS) while tracking a target. A significant tactic to realize tracking without PDS interception is to study the low probability of interception (LPI) time of NARS. Firstly, this paper analyses the power, frequency, and platform interception probabilities of a combined PDS consisting of a radar-warning receiver (RWR) and an electronic support measurement (ESM). Secondly, this paper takes interactive multiple models (IMM) to describe the target tracking process and introduces a binary hypothesis test for chi square as well as noncentralized chi square distributions as a detection criterion of NARS during target tracking after the design of adaptive dwell time and the maximum illumination interval algorithm. Finally, based on experiential moving platform interception probabilities of a RWR and an ESM, a simplified math model is presented to estimate LPI time of NARS when the parameters are partially known. Simulations illustrate that the simultaneous management of radiation power and time is crucial for NARS against combined PDS interception.
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Righi, Ciro Abbud, Marcos Silveira Bernardes, Aureny Maria Pereira Lunz, Carlos Rodrigues Pereira, Durval Dourado Neto e José Laercio Favarin. "Measurement and simulation of solar radiation availability in relation to the growth of coffee plants in an agroforestry system with rubber trees". Revista Árvore 31, n. 2 (aprile 2007): 195–207. http://dx.doi.org/10.1590/s0100-67622007000200002.
Testo completoAbstract (sommario):
Solar radiation is an important factor for plant growth, being its availability to understory crops strongly modified by trees in an Agroforestry System (AFS). Coffee trees (Coffea arabica - cv. Obatã IAC 1669-20) were planted at a 3.4 x 0.9 m spacing inside and aside rows of monocrops of 12 year-old rubber trees (Hevea spp.), in Piracicaba-SP, Brazil (22º42'30" S, 47º38'00" W - altitude: 546m). One-year-old coffee plants exposed to 25; 30; 35; 40; 45; 80; 90; 95 and 100% of the total solar radiation were evaluated according to its biophysical parameters of solar radiation interception and capture. The Goudriaan (1977) adapted by Bernardes et al. (1998) model for radiation attenuation fit well to the measured data. Coffee plants tolerate a decrease in solar radiation availability to 50% without undergoing a reduction on growth and LAI, which was approximately 2m².m-2 under this condition. Further reductions on the availability of solar radiation caused a reduction in LAI (1.5m².m-2), thus poor land cover and solar radiation interception, resulting in growth reduction.
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Augspurger, Carol K., e Carl F. Salk. "Understory plants evade shading in a temperate deciduous forest amid climate variability by shifting phenology in synchrony with canopy trees". PLOS ONE 19, n. 6 (26 giugno 2024): e0306023. http://dx.doi.org/10.1371/journal.pone.0306023.
Testo completoAbstract (sommario):
Global warming is leading understory and canopy plant communities of temperate deciduous forests to grow leaves earlier in spring and drop them later in autumn. If understory species extend their leafy seasons less than canopy trees, they will intercept less light. We look for mismatched phenological shifts between canopy and understory in 28 years (1995–2022) of weekly data from Trelease Woods, Urbana, IL, USA. The observations cover 31 herb species of contrasting seasonality (for 1995–2017), three sapling species, and the 15 most dominant canopy tree species for all years, combined with solar radiation, temperature and canopy light transmittance data. We estimate how understory phenology, cold temperatures, canopy phenology, and solar radiation have individually limited understory plants’ potential light interception over >2 decades. Understory and canopy phenology were the two factors most limiting to understory light availability, but which was more limiting varied greatly among species and among/within seasonality groups; solar radiation ranked third and cold fourth. Understory and canopy phenology shifts usually occurred in the same direction; either both strata were early or both were late, offsetting each other’s effects. The four light-limiting factors combined showed significant temporal trends for six understory species, five toward less light interception. Warmer springs were significantly associated with shifts toward more light interception in three sapling species and 19 herb species. Canopy phenology became more limiting in warmer years for all three saplings species and 31 herb species. However, in aggregate, these variables mostly offset one another; only one sapling and seven herb species showed overall significant (and negative) relationships between light interception and spring temperature. The few understory species mismatched with canopy phenology due to changing climate are likely to intercept less light in future warmer years. The few species with data for carbon assimilation show broadly similar patterns to light interception.
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Wünsche, Jens N., Alan N. Lakso e Terence L. Robinson. "Comparison of Four Methods for Estimating Total Light Interception by Apple Trees of Varying Forms". HortScience 30, n. 2 (aprile 1995): 272–76. http://dx.doi.org/10.21273/hortsci.30.2.272.
Testo completoAbstract (sommario):
Four methods of estimating daily light interception (fisheye photography with image analysis, multiple-light sensors, ceptometer, and point grid) were compared using various apple (Malus domestica Borkh.) tree forms: slender spindle, Y- and T-trellises, and vertical palmette. Interactions of tree form, time of day, and atmospheric conditions with light interception estimates were examined. All methods were highly correlated to each other (r2 > 0.92) for estimated daily mean percent total light interception by the various tree forms, except that the point grid method values were slightly lower. Interactions were found among tree form, time of day, and diffuse/direct radiation balance on estimated light interception, suggesting that several readings over the day are needed under clear skies, especially in upright canopies. The similar results obtained by using the point grid method (counting shaded/exposed points on a grid under the canopy) on clear days may allow rapid, simple, and inexpensive estimates of orchard light interception.
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Elhakeem, Ali, Wopke van der Werf e Lammert Bastiaans. "Radiation interception and radiation use efficiency in mixtures of winter cover crops". Field Crops Research 264 (maggio 2021): 108034. http://dx.doi.org/10.1016/j.fcr.2020.108034.
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Ligot, Gauthier, Aitor Ameztegui, Benoît Courbaud, Lluís Coll e Dan Kneeshaw. "Tree light capture and spatial variability of understory light increase with species mixing and tree size heterogeneity". Canadian Journal of Forest Research 46, n. 7 (luglio 2016): 968–77. http://dx.doi.org/10.1139/cjfr-2016-0061.
Testo completoAbstract (sommario):
Mixed and multi-layered forest ecosystems are sometimes more productive than monospecific and single-layered ones. It has been suggested that trees of different species and sizes occupy complementary positions in space, which would act as a mechanism to increase canopy light interception and wood production. However, greater canopy light interception reduces the average amount and variability of transmitted radiation, offering fewer opportunities for all species to regenerate and to maintain forest heterogeneity in the long run. We investigated whether increasing overstory heterogeneity indeed results in greater canopy light interception and lower variability in transmittance. We modeled the three-dimensional structure of forest stands with three typical forest structures, 10 mixtures of four tree species, and three different basal areas. We used the forest light interception model SamsaraLight and performed three-way analyses of covariance to analyze the effects of the three varied components of forest heterogeneity. We found no evidence that increasing structural heterogeneity increases canopy light interception. However, the light interception by mixed canopies was greater than the weighted average of light interception by the corresponding pure canopies. Variability in transmittance increased in some cases with compositional heterogeneity and, to a lesser extent, with tree size inequalities. The advantage of heterogeneous forests is in opportunities for natural regeneration, as well as in opportunities to enhance canopy light interception.
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Mubarak, Syahrun, Impron , e Dan Tania June. "Efisiensi Penggunaan Radiasi Matahari dan Respon Tanaman Kedelai (Glycine max L.) terhadap Penggunaan Mulsa Reflektif". Jurnal Agronomi Indonesia (Indonesian Journal of Agronomy) 46, n. 3 (25 gennaio 2019): 247–53. http://dx.doi.org/10.24831/jai.v46i3.18220.
Testo completoAbstract (sommario):
One of factors affecting the productivity of soybean crop is the availability of solar radiation. Reduction of solar radiation reaching soybean crop by cloud cover especially during rainy season or by shade of trees could potentially decrease soybean production. The availability of radiation for the crop can be increased through the use of reflective mulch to reflect back transmitted radiation to the crop canopy. This study aimed to determine the effect of shade and reflective mulch on crop solar radiation balance and crop productivity responses. A field experiment in Bogor, Indonesia in July 2016 to January 2017, was conducted, applying a Nested Design-two factors model with three replications. The first factor was two levels of shading, i.e., without and with 50% shade; and the second factor was three levels, i.e., without mulch, black silver mulch, and metallic mulch. The results showed that the use of mulch influenced the radiation balance of plants, increasing distribution of radiation reception in plants, solar radiation interception and RUE. The use of mulch caused changes in canopy structure by increase LAI, so that the inhibited radiation was higher. The reflected radiation from the mulch increased production per plants and weight of 1,000 seeds in shaded plants.Keywords: black silver mulch, metallic mulch, radiation balance, radiation interception, shading
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Burstall, Lindsay, e P. M. Harris. "The physiological basis for mixing varieties and seed ‘ages’ in potato crops". Journal of Agricultural Science 106, n. 2 (aprile 1986): 411–18. http://dx.doi.org/10.1017/s0021859600064029.
Testo completoAbstract (sommario):
SUMMARYThree techniques designed to increase radiation interception, and thus yield, in potato crops by extending the duration of the crop canopy were investigated over a period of 2 years. These were: mixing contrasting varieties; mixing seed tubers of contrasting physiological ages of the same variety, and early planting with protection from frost.The first technique was partially successful; increases in total tuber fresh weight of the mixture over either of its components grown alone were recorded but the mixtures generally did not have any advantage in terms of ware yield (40–80 mm tubers) and total yield advantages were found in only 1 year. The second technique was unsuccessful in both years with all seven varieties tested. The third technique was successful with the long-lived variety Cara; large advantages both in ware yield and total tuber dry weight yield were obtained under two irrigation regimes. No advantages from early planting were obtained with the shorter-lived variety King Edward.Radiation interception was estimated for all treatments by means of relationships established between intercepted radiation and percentage ground cover. None of the three techniques increased radiation interception; the yield advantages obtained could be ascribed either to an increase in the proportion of assimilates allocated to tubers or possibly to improvements in the efficiency of use of intercepted radiation.
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Prihar, S. S., V. K. Arora, G. Singh e R. Singh. "Estimating Potato Tuber Yield in a Sub-tropical Environment with Simple Radiation-Based Models". Experimental Agriculture 31, n. 1 (gennaio 1995): 65–73. http://dx.doi.org/10.1017/s0014479700025023.
Testo completoAbstract (sommario):
SummaryDry matter and tuber yields of potato grown in a sub-tropical environment were estimated employing simple radiation-based models which require meteorological information on air temperature and solar radiation. Two versions of the MacKerron and Waister (1985) model, in which estimation of dry matter accumulation relies on a single composite parameter, radiation use efficiency (RUE), were compared with the Versteeg and Van Keulen (1986) model, which explicitly accounts for temperature and radiation effects on dry matter accumulation. In the original version of the MacKerron and Waister model, a linear change in the radiation interception factor with leaf area index is assumed; in the modified version an exponential change in the interception factor with leaf area index is considered. The accumulation of dry matter estimated from all three models was close to the measured values throughout the growing season, but estimates of tuber yield differed widely. Our analysis showed that the best agreement with measured values was obtained using the MacKerron and Waister linear model with RUE values adjusted according to the incident radiation level.Estimatión del rendimiento del tubérculo de la patata
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Leach, GJ, e DF Beech. "Response of chickpea accessions to row spacing and plant density on a vertisol on the Darling Downs, south-eastern Queensland. 2. Radiation interception and water use". Australian Journal of Experimental Agriculture 28, n. 3 (1988): 377. http://dx.doi.org/10.1071/ea9880377.
Testo completoAbstract (sommario):
Interception of radiation by chickpea (Cicer arietinum L.), in a year of below-average rainfall, and water use in both wet and dry years, were studied on a deep vertisol soil at Dalby, south-eastern Queensland. Measurements were made on 4 accessions (cv. Tyson, K223, CPI 56287 and CPI 56289) grown at a number of row spacings. Canopies intercepted less than 20% of incident radiation during the first 70 days after sowing (DAS) in the dry year (1980) before radiation interception reached a peak in mid-September (100 DAS) at about 70% interception in 250 mm rows. Above-ground dry matter was linearly related to intercepted radiation to the end of September (119 DAS), giving an efficiency of radiation conversion of 1.4 g DM per MJ of intercepted photosynthetically active radiation. Efficiency of conversion was marginally higher with 125 mm than with 62.5 mm intra-row spacing in rows 250 mm apart. In a wet year (1979), chickpea extracted water from below 1 m depth in the soil profile and used 356 mm water. In the dry year, only 16 1 mm water was used and none was extracted from below 1 m. K223 used water faster than cv. Tyson, and extraction was faster with close than with wide row spacing. Above-ground dry matter was produced at an efficiency of 3.4 (1980) to 4.2 (1979) g m-2 mm-I of water during the main period of growth through September, and a mean of 0.7 g m-2 seed for 2 seasons was produced per mm of water used over the whole season. The small differences in water extraction between accessions and spacing treatments were reflected during pod-filling as differences in plant water potential of 0.1-0.2 MPa during the early afternoon stress period. Chickpea appears to have poor stomata1 control over water loss, being comparable to summer legumes like soybean rather than to cowpea. We conclude that the benefit of close row spacing in enhancing radiation interception outweighs the small disadvantage from accelerated water depletion. The ability of chickpea to produce useful seed yields over a wide range of soil water availability makes it well suited for opportunistic winter cropping.
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Robinson, Terence L., e Alan N. Lakso. "Bases of Yield and Production Efficiency in Apple Orchard Systems". Journal of the American Society for Horticultural Science 116, n. 2 (marzo 1991): 188–94. http://dx.doi.org/10.21273/jashs.116.2.188.
Testo completoAbstract (sommario):
Bases of orchard productivity were evaluated in four 10-year-old apple orchard systems (`Empire' and `Redchief Delicious' Malus domestics Borkh. on slender spindle/M.9, Y-trellis/M.26, central leader/M.9/MM.111, and central leader/M.7a). Trunk cross-sectional areas (TCA), canopy dimension and volume, and light interception were measured. Canopy dimension and canopy volume were found to be relatively poor estimators of orchard light interception or yield, especially for the restricted canopy of the Y-trellis. TCA was correlated to both percentage of photosynthetically active radiation (PAR) intercepted and yields. Total light interception during the 7th to the 10th years showed the best correlation with yields of the different systems and explained most of the yield variations among systems. Average light interception was highest with the Y-trellis/M.26 system of both cultivars and approached 70% of available PAR with `Empire'. The higher light interception of this system was the result of canopy architecture that allowed the tree canopy to grow over the tractor alleys. The central leader/M.7a had the lowest light interception with both cultivars. The efficiency of converting light energy into fruit (conversion efficiency = fruit yield/light intercepted) was significantly higher for the Y-trellis/M.26 system than for the slender spindle/M.9 or central leader/M.9/MM.111 systems. The central leader/M.7a system bad the lowest conversion efficiency. An index of partitioning was calculated as the kilograms of fruit per square centimeter increase in TCA. The slender spindle/M.9 system had significantly higher partitioning index than the Y-trellis/M.26 or central leader/M.9/MM.111. The central leader/M.7a system had the lowest partitioning index. The higher conversion efficiency of the Y/M.26 system was not due to increased partitioning to the fruit; however, the basis for the greater efficiency is unknown. The poor conversion efficiency of the central leader/M.7a was mostly due to low partitioning to the fruit. The Y-trellis/M.26 system was found to be the most efficient in both intercepting PAR and converting that energy into fruit.
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Bergamaschi, Homero, Genei Antonio Dalmago, João Ito Bergonci, Cleusa Adriane Menegassi Bianchi Krüger, Bruna Maria Machado Heckler e Flavia Comiran. "Intercepted solar radiation by maize crops subjected to different tillage systems and water availability levels". Pesquisa Agropecuária Brasileira 45, n. 12 (dicembre 2010): 1331–41. http://dx.doi.org/10.1590/s0100-204x2010001200001.
Testo completoAbstract (sommario):
The objective of this work was to evaluate changes in the photosynthetic photon flux density (PPFD) interception efficiency and PPFD extinction coefficient for maize crop subjected to different soil tillage systems and water availability levels. Crops were subjected to no-tillage and conventional tillage systems combined with full irrigation and non-irrigation treatments. Continuous measurements of transmitted PPFD on the soil surface and incoming PPFD over the canopy were taken throughout the crop cycle. Leaf area index and soil water potential were also measured during the whole period. Considering a mean value over the maize cycle, intercepted PPFD was higher in the conventional tillage than in the no-tillage system. During the initial stages of plants, intercepted PPFD in the conventional tillage was double the PPFD interception in the no-tillage treatment. However, those differences were reduced up to the maximum leaf area index, close to tasseling stage. The lowest interception of PPFD occurred in the conventional tillage during the reproductive period, as leaf senescence progressed. Over the entire crop cycle, the interception of PPFD by the non-irrigated plants was about 20% lower than by the irrigated plants. The no-tillage system reduced the extinction coefficient for PPFD, which may have allowed a higher penetration of solar radiation into the canopy
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Herrero, Alicia, Santiago Moll, José-A. Moraño, David Vázquez e Erika Vega. "Iterative Lambert’s Trajectory Optimization for Extrasolar Bodies Interception". Aerospace 8, n. 12 (27 novembre 2021): 366. http://dx.doi.org/10.3390/aerospace8120366.
Testo completoAbstract (sommario):
Interception of extrasolar objects is one of the major current astrophysical objectives since it allows gathering information on the formation and composition of other planetary systems. This paper develops a tool to design optimal orbits for the interception of these bodies considering the effects of different perturbation sources. The optimal trajectory is obtained by solving a Lambert’s problem that gives the required initial impulse. A numerical integration of a perturbed orbital model is calculated. This model considers the perturbations of the joint action of the gravitational potentials of the Solar System planets and the solar radiation pressure. These effects cause a deviation in the orbit that prevents the interception from taking place, so an iterative correction scheme of the initial estimated impulse is presented, capable of modifying the orbit and achieving a successful interception in a more realistic environment.