scholarly journals Light Use Efficiency of Aboveground Biomass Production of Norway Spruce Stands

2017 ◽  
Vol 65 (1) ◽  
pp. 9-16
Author(s):  
Michal Bellan ◽  
Irena Marková ◽  
Andrii Zaika ◽  
Jan Krejza
Keyword(s):  
Norway Spruce ◽  
Aboveground Biomass ◽  
Photosynthetically Active Radiation ◽  
Climatic Conditions ◽  
Light Use Efficiency ◽  
Active Radiation ◽  
Spruce Stands ◽  
Use Efficiency ◽  
Study Sites ◽  
Radiation Use

Light use efficiency (LUE or photosynthetically active radiation use efficiency) in production of young spruce stands aboveground biomass was determined at the study sites Rájec (the Drahanská vrchovina Highland) and Bílý Kříž (the Moravian‑Silesian Beskids Mountains) in 2014 and 2015. The LUE value obtained for the investigated spruce stands were in the range of 0.45 – 0.65 g DW MJ–1. The different LUE values were determined for highland and mountain spruce stand. The differences were caused by growth and climatic conditions and by the amount of assimilatory apparatus (LAI).

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 Radiation Use Efficiency for Cowpea Subjected to Different Irrigation Depths Under the Climatic Conditions of the Northeast Of Pará State

2018 ◽  
Vol 33 (4) ◽  
pp. 579-587
Author(s):  
Denis de Pinho Sousa ◽  
Paulo Jorge Oliveira Ponte de Souza ◽  
Vivian Dielly da Silva Farias ◽  
Hildo Giuseppe Caldas Nunes ◽  
Denílson Pontes Ferreira ◽  
...  
Keyword(s):  
Water Deficit ◽  
Dry Matter ◽  
Climatic Conditions ◽  
Radiation Use Efficiency ◽  
Crop Evapotranspiration ◽  
Area Index ◽  
Active Radiation ◽  
Use Efficiency ◽  
Radiation Use ◽  
Absorbed Photosynthetically Active Radiation

Abstract This study aims to determine the cowpea efficiency in absorbing and using solar radiation according to different irrigation depths under the climatic conditions of the northeast of Pará State. The experiment was carried out on 2014 and 2016 in an experimental design of randomized blocks, which consisted in six blocks with four treatments, in which different irrigation depths the reproductive phase were applied, as follows: T100, T50, T25 e T0, that corresponded to 100%, 50%, 25% e 0% of the crop evapotranspiration, respectively. The absorbed photosynthetically active radiation, leaf area index (LAI), total aerial dry matter (TADM) and grain yield were measured. The extinction coefficient (k) was obtained by nonlinear regression between the fraction of absorbed PAR (fPARinter) and the LAI. The radiation use efficiency (RUE) was calculated by linear regression between the TADM and the accumulated absorbed PAR. The water deficit imposed by the treatments had a significant influence on the LAI, TADM and cowpea yields. The water deficit did not significantly influenced k – it ranged between 0.83 for T100 and 0.70 for T0. The RUE showed significant behaviors regarding the treatments with adequate water supply and treatments under water deficit, ranging from 2.23 to 1.64 g·MJ-1, respectively.

A Pear and Vegetable Interculture System: Land Equivalent Ratio, Light Use Efficiency and Productivity

1986 ◽  
Vol 22 (4) ◽  
pp. 383-392 ◽  
Author(s):  
S. M. Newman
Keyword(s):  
Photosynthetically Active Radiation ◽  
Dry Matter ◽  
Spatial Arrangement ◽  
Yield Reduction ◽  
Light Use Efficiency ◽  
Land Equivalent Ratio ◽  
Active Radiation ◽  
Use Efficiency ◽  
Pear Trees ◽  
Efficiency And Productivity

SUMMARYThe productivity, land equivalent ratios (LERs) and light use efficiency of a pear and radish interculture system were assessed. Pear yield was unaffected by intercropping. Relative yields for the radish component varied between 0.5–1.01 depending upon the yield index and spatial arrangement employed. This gave LER values for the system of 1.5–2.01. The overall trans-missivity of the pear canopy was 73%. A 47% reduction in photosynthetically active radiation (PAR) gave a yield reduction of 65% in terms of number of saleable radish, but did not affect total dry matter productivity. Reductions in radish yield directly beneath pear trees was thought to be due to other factors besides PAR. The total dry matter productivity of a system containing five successive radish crops was estimated at 26.25 tonnes ha−1 yr−1.

scholarly journals Effect of tillage, residue and nitrogen management on radiation interception, radiation use efficiency and evapotranspiration partitioning

2021 ◽  
Vol 22 (3) ◽  
pp. 285-294
Author(s):  
KOUSHIK BAG ◽  
K.K. BANDYOPADHYAY ◽  
V.K. SEHGAL ◽  
A. SARANGI ◽  
P. KRISHNAN
Keyword(s):  
Leaf Area ◽  
Photosynthetically Active Radiation ◽  
Crop Residue ◽  
Radiation Use Efficiency ◽  
Area Index ◽  
Radiation Interception ◽  
Active Radiation ◽  
Biomass Yields ◽  
Use Efficiency ◽  
Radiation Use

In this study, we have evaluated the effect of different tillage (conventional tillage (CT) and no tillage (NT)), residue (with crop residue mulch (R+) and without residue (R0)) and nitrogen (60, 120 and 180 kgN ha-1) interaction for radiation interception, radiation use efficiency (RUE), evapotranspiration (ET) partitioning and yield of wheat in a split-split plot design for 2017-18 and 2018-19. Results showed that Leaf Area Index (LAI), Leaf area duration (LAD), Total intercepted photosynthetically active radiation (TIPAR), Grain and Biomass yields were higher in R+ during both the years of study. With increasing Ndoses LAI, LAD, TIPAR, RUE, grain and biomass yields increased and extinction coefficient decreased significantly in both the years. Fraction intercepted photosynthetically active radiation (fIPAR) followed a similar trend with LAI. Seasonal ET was partitioned into soil evaporation (Ep) and crop transpiration (Tp) to take into account the productive transpiration effects on crop growth and yield. It was found that NT and residue could reduce Ep (6% and 5.6%) and increased Tp (2.6% and 2.4%) over CT and no mulch treatments, respectively. With higher N-dose, Ep decreased while Tp increased significantly. Thus besides higher nitrogen doses, NT and crop residue mulching could be a better strategy to harness higher radiation interception vis-a-vis higher crop productivity.

scholarly journals Using MODIS derived <i>f</i>PAR with ground based flux tower measurements to derive the light use efficiency for two Canadian peatlands

2008 ◽  
Vol 5 (2) ◽  
pp. 1765-1794 ◽  
Author(s):  
J. Connolly ◽  
N. T. Roulet ◽  
J. W. Seaquist ◽  
N. M. Holden ◽  
P. M. Lafleur ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Photosynthetically Active Radiation ◽  
Vapour Pressure Deficit ◽  
Remote Sensing Data ◽  
Limiting Factor ◽  
Light Use Efficiency ◽  
Active Radiation ◽  
Flux Tower ◽  
Use Efficiency ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. We used satellite remote sensing data; fraction of photosynthetically active radiation absorbed by vegetation (fPAR) from the Moderate Resolution Imaging Spectroradiometer (MODIS) in combination with tower eddy covariance and meteorological measurements to characterise the light use efficiency parameter (ε) variability and the maximum ε (εmax) for two contrasting Canadian peatlands. Eight-day MODIS fPAR data were acquired for the Mer Bleue (2000 to 2003) and Western Peatland (2004). Flux tower eddy covariance and meteorological measurements were integrated to the same eight-day time stamps as the MODIS fPAR data. A light use efficiency model: GPP=ε * APAR (where GPP is Gross Primary Productivity and APAR is absorbed photosynthetically active radiation) was used to calculated ε. The εmax value for each year (2000 to 2003) at the Mer Bleue bog ranged from 0.58 g C MJ−1 to 0.78 g C MJ−1 and was 0.91 g C MJ−1 in 2004, for the Western Peatland. The average growing season ε for the Mer Bleue bog for the four year period was 0.35 g C MJ−1 and for the Western Peatland in 2004 was 0.57 g C MJ−1. The average snow free period ε for the Mer Bleue bog over the four year period was 0.27 g C MJ−1 and for the Western Peatland in 2004 was 0.39 g C MJ−1. Using the light use efficiency method we calculated the εmax and the annual variability in ε for two Canadian peatlands. We determined that temperature was a growth-limiting factor at both sites Vapour Pressure Deficit (VPD) however was not. MODIS fPAR is a useful tool for the characterization of ε at flux tower sites.

scholarly journals Identification of a general light use efficiency model for gross primary production

2010 ◽  
Vol 7 (5) ◽  
pp. 7673-7726 ◽  
Author(s):  
J. E. Horn ◽  
K. Schulz
Keyword(s):  
Large Scale ◽  
Gross Primary Production ◽  
Daily Basis ◽  
Climatic Conditions ◽  
Model Parameters ◽  
Light Use Efficiency ◽  
Meteorological Forcing ◽  
Use Efficiency ◽  
Study Sites ◽  
Light Use Efficiency Model

Abstract. Non-stationary and non-linear dynamic time series analysis tools are applied to multi-annual eddy covariance and micrometeorological data from 45 FLUXNET sites to derive a light use efficiency model on a daily basis. The extracted typical behaviour of the canopies in response to meteorological forcing leads to a model formulation allowing a variable influence of the model parameters modulating the light use efficiency. Thereby, the model is applicable to a broad range of vegetation types and climatic conditions. The proposed model explains large proportions of the variation of the gross carbon uptake at the study sites while the optimized set of six parameters is well defined. With the parameters showing explainable and meaningful relations to site-specific environmental conditions, the model has the potential to serve as basis for general regionalization strategies for large scale carbon flux predictions.

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