scholarly journals Estimating the yield potential of short-rotation willow in Canada using the 3PG model

2017 ◽  
Vol 47 (5) ◽  
pp. 636-647 ◽  
Author(s):  
Guillaume Jégo ◽  
François Thibodeau ◽  
René Morissette ◽  
Marianne Crépeau ◽  
Annie Claessens ◽  
...  
Keyword(s):  
Large Scale ◽  
Model Performance ◽  
Stem Growth ◽  
Yield Potential ◽  
Growing Degree Days ◽  
Degree Days ◽  
Area Index ◽  
Stem Biomass ◽  
Short Rotation ◽  
Simulation Results

The ability to predict short-rotation coppice (SRC) willow productivity for a given region would be very helpful for large-scale deployment of this crop. The objectives of this study were to calibrate and validate the 3PG model for two commonly used clones (SX64 and SX67) and to provide yield potential estimates for 16 sites across Canada. One dataset for each clone, including leaf area index (LAI) and stem biomass, was used for calibrating parameters controlling leaf and stem growth. All other datasets, coming from eight different willow plantations, were used for model validation. Model performance was good in predicting stem biomass for the SX64 (normalized mean error (NME) = –8%, normalized root mean square error (NRMSE) = 22%) and SX67 (NME = –3%, NRMSE = 16%) clones. Predictions were more scattered for LAI, with NRMSE close to 35% and 33% and NME of 1% and 8% for SX64 and SX67, respectively. The simulation results show that the greatest yields were obtained with the three-year rotation for the SX67 clone, whereas a two-year rotation seemed to be more appropriate for the SX64 clone. The simulation results also show that growing degree-days had a significant impact on yield potential, which varied from 10.5 to 16.5 t DM·ha−1 for SX64 and from 7.5 to 11.5 t DM·ha−1 for SX67.

Evaluation of Finger Millet Varieties under Rainfed Condition of Eastern India

2017 ◽  
Vol 4 (03) ◽  
Author(s):  
M. K. Singh ◽  
VINOD KUMAR ◽  
SHAMBHU PRASAD
Keyword(s):  
Field Experiment ◽  
Finger Millet ◽  
Yield Potential ◽  
Growing Degree Days ◽  
Eastern India ◽  
Degree Days ◽  
Rainfed Condition ◽  
Net Returns ◽  
Humid Environment ◽  
Use Efficiency

A field experiment was carried out during the kharif of 2014 and 2015 to evaluate the yield potential, economics and thermal utilization in eleven finger millet varieties under the rainfed condition of the sub-humid environment of South Bihar of Eastern India. Results revealed that the significantly higher grain yield (20.41 q ha-1), net returns (Rs 25301) and B: C ratio (1.51) was with the finger millet variety ‘GPU 67’ but was being at par to ‘GPU28’and ‘RAU-8’, and significantly superior over remaining varieties. The highest heat units (1535.1oC day), helio-thermal units (7519.7oC day hours), phenothermal index (19.4 oC days day-1) were recorded with variety ‘GPU 67’ followed by ‘RAU 8’ and ‘GPU 28’ and lowest in ‘VL 149’ at 50 % anthesis stage. Similarly, the highest growing degree days (2100 oC day), helio-thermal units (11035.8 oC day hours) were noted with ‘GPU 67’ followed by ‘RAU 8’ and ‘GPU 28’ at maturity. The highest heat use efficiency (0.97 kg ha-1 oC day) and helio-thermal use efficiency (0.19 kg ha-1 oC day hour) were in ‘GPU 67’ followed by ‘VL 315’.

The Critical Weed-Free Period in Carrot

Weed Science ◽  
2010 ◽  
Vol 58 (3) ◽  
pp. 229-233 ◽  
Author(s):  
Clarence J. Swanton ◽  
John O'Sullivan ◽  
Darren E. Robinson
Keyword(s):  
Yield Potential ◽  
Growing Degree Days ◽  
Herbicide Application ◽  
Degree Days ◽  
Weed Biomass ◽  
Seeding Date ◽  
Weed Emergence

Seeding date and the duration of weed emergence influenced the duration of the critical weed-free period in carrot. The critical weed-free period extended up to 930 growing degree days (GDD), when carrot was seeded in late April. In contrast, the critical weed-free period was short and lasted 414 to 444 GDD, when seeded in mid to late May and weed biomass was less than 650 g m−2. It is important for growers to scout fields for weeds until 930 GDD to protect the yield potential of the carrot crop in earlier planted crops; however, for carrot planted in mid to late May, weeds emerging after 444 GDD did not reduce yield. A useful strategy to reduce reliance on herbicide application would be to delay planting until late in May.

Forest ecotone response to climate change: sensitivity to temperature response functional forms

2000 ◽  
Vol 30 (10) ◽  
pp. 1632-1645 ◽  
Author(s):  
Craig Loehle
Keyword(s):  
Response Function ◽  
Large Scale ◽  
Temperature Response ◽  
Tree Height ◽  
Growing Degree Days ◽  
Degree Days ◽  
Functional Responses ◽  
New Model ◽  
Functional Forms ◽  
Response To Temperature

Past simulation studies using a variety of models have generally agreed that climatic warming could have adverse effects on forests, including large-scale diebacks in some regions and drastic range shrinkages of many species. These effects should be most evident at biome transition zones. Other studies have pointed out, however, that past models have used a parabolic temperature response function that is based on geographic range limits rather than functional responses or data and that this parabolic model could exaggerate dieback effects. A new model is proposed for growing degree-days temperature response, which is asymptotic rather than parabolic. In this new model, tree height growth rate increases and then levels off with increasing growing degree-days. Species from more southern regions have a higher asymptote. It is shown that this model can be derived from the integration of a parabolic growth response to temperature over a year-long sinusoidal temperature regime. The SORTIE forest simulation model was modified to incorporate this response function. An ecotonal region was simulated under a warming scenario. The traditional parabolic temperature response model produced a wide zone of dieback following warming. In contrast, the new asymptotic response function produced no dieback and a stable ecotone that migrated north at <100 m/100 years.

GROWTH CHARACTERISTICS, YIELD COMPONENTS AND RATE OF GRAIN DEVELOPMENT OF TWO HIGH-YIELDING WHEATS, HY320 AND DT367, COMPARED TO TWO STANDARD CULTIVARS, NEEPAWA AND WAKOOMA

1988 ◽  
Vol 68 (4) ◽  
pp. 915-928 ◽  
Author(s):  
H. W. CUTFORTH ◽  
C. A. CAMPBELL ◽  
Y. W. JAME ◽  
J. M. CLARKE ◽  
R. M. DePAUW
Keyword(s):  
Yield Components ◽  
Harvest Index ◽  
Unit Area ◽  
Kernel Weight ◽  
Yield Potential ◽  
Base Temperature ◽  
Grain Development ◽  
Degree Days ◽  
Area Index ◽  
Kernel Growth

A high-yielding Canada Prairie Spring (CPS cv. HY320) semi-dwarf wheat and a high-yielding durum line (DT367) were compared to standard hard red spring (cv. Neepawa) and durum (cv. Wakooma) wheats to assess the basis for the yield differences and to examine soil moisture use. The study was carried out under dryland (moisture used from seeding to harvest was 287 mm), partial irrigation (moisture used was 374 mm) and full irrigation (moisture used was 547 mm) on a loam soil at Swift Current during 3 yr. Phenological development was delayed as much as 30 d by improved moisture conditions. At ligule of last leaf visible (LLV), HY320 had one or two more green leaves on the main tiller than did Neepawa; Wakooma generally had one more leaf than DT367. However, leaf area index was generally not different among cultivars. Harvest index was greater for the higher yielding cultivars even though cultivars did not differ in total aboveground dry matter. HY320 generally had the highest grain yield, followed by DT367, Wakooma and Neepawa. Neepawa consistently had the most heads per unit area at harvest but, because of high kernel numbers per head, HY320 produced the greatest number of kernels per unit area; as well, HY320 had large kernels; thus, it had the highest yield potential under optimum growing conditions. HY320 had the highest base temperature (Tb) for kernel growth and the highest kernel growth rates immediately after anthesis; consequently, HY320 kernels completed growth with the lowest accumulated degree days above Tb. DT367 had the highest potential kernel weight and Neepawa the lowest. There were no differences among the cultivars in the amount of moisture used between seeding and harvest.Key words: Wheat (Spring), yield components, grain development, moisture use, growing degree days, harvest index

scholarly journals Determining the critical period for weed control in high-yielding cotton using common sunflower as a mimic weed

2019 ◽  
Vol 33 (6) ◽  
pp. 800-807 ◽  
Author(s):  
Graham W. Charles ◽  
Brian M. Sindel ◽  
Annette L. Cowie ◽  
Oliver G. G. Knox
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Field Studies ◽  
Growing Degree Days ◽  
Degree Days ◽  
Weed Density ◽  
High Level ◽  
The Cost ◽  
Planting Season

AbstractField studies were conducted over six seasons to determine the critical period for weed control (CPWC) in high-yielding cotton, using common sunflower as a mimic weed. Common sunflower was planted with or after cotton emergence at densities of 1, 2, 5, 10, 20, and 50 plants m−2. Common sunflower was added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 growing degree days (GDD) after planting. Season-long interference resulted in no harvestable cotton at densities of five or more common sunflower plants m−2. High levels of intraspecific and interspecific competition occurred at the highest weed densities, with increases in weed biomass and reductions in crop yield not proportional to the changes in weed density. Using a 5% yield-loss threshold, the CPWC extended from 43 to 615 GDD, and 20 to 1,512 GDD for one and 50 common sunflower plants m−2, respectively. These results highlight the high level of weed control required in high-yielding cotton to ensure crop losses do not exceed the cost of control.

scholarly journals Design and Evaluation of Large-Scale IoT-Enabled Healthcare Architecture

2021 ◽  
Vol 11 (8) ◽  
pp. 3623
Author(s):  
Omar Said ◽  
Amr Tolba
Keyword(s):  
Packet Loss ◽  
Large Scale ◽  
Performance Metrics ◽  
Medical System ◽  
Healthcare Data ◽  
High Altitude Platforms ◽  
Wide Range ◽  
Simulation Results ◽  
Healthcare Architecture ◽  
The Internet Of Things

Employment of the Internet of Things (IoT) technology in the healthcare field can contribute to recruiting heterogeneous medical devices and creating smart cooperation between them. This cooperation leads to an increase in the efficiency of the entire medical system, thus accelerating the diagnosis and curing of patients, in general, and rescuing critical cases in particular. In this paper, a large-scale IoT-enabled healthcare architecture is proposed. To achieve a wide range of communication between healthcare devices, not only are Internet coverage tools utilized but also satellites and high-altitude platforms (HAPs). In addition, the clustering idea is applied in the proposed architecture to facilitate its management. Moreover, healthcare data are prioritized into several levels of importance. Finally, NS3 is used to measure the performance of the proposed IoT-enabled healthcare architecture. The performance metrics are delay, energy consumption, packet loss, coverage tool usage, throughput, percentage of served users, and percentage of each exchanged data type. The simulation results demonstrate that the proposed IoT-enabled healthcare architecture outperforms the traditional healthcare architecture.

scholarly journals Process-Based Model Prediction of Coastal Dune Erosion through Parametric Calibration

2021 ◽  
Vol 9 (6) ◽  
pp. 635
Author(s):  
Hyeok Jin ◽  
Kideok Do ◽  
Sungwon Shin ◽  
Daniel Cox
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Model Performance ◽  
Coastal Dunes ◽  
Wave Transformation ◽  
Storm Event ◽  
Face Model ◽  
Dune Erosion ◽  
Simulation Performance ◽  
Sand Bar

Coastal dunes are important morphological features for both ecosystems and coastal hazard mitigation. Because understanding and predicting dune erosion phenomena is very important, various numerical models have been developed to improve the accuracy. In the present study, a process-based model (XBeachX) was tested and calibrated to improve the accuracy of the simulation of dune erosion from a storm event by adjusting the coefficients in the model and comparing it with the large-scale experimental data. The breaker slope coefficient was calibrated to predict cross-shore wave transformation more accurately. To improve the prediction of the dune erosion profile, the coefficients related to skewness and asymmetry were adjusted. Moreover, the bermslope coefficient was calibrated to improve the simulation performance of the bermslope near the dune face. Model performance was assessed based on the model-data comparisons. The calibrated XBeachX successfully predicted wave transformation and dune erosion phenomena. In addition, the results obtained from other two similar experiments on dune erosion with the same calibrated set matched well with the observed wave and profile data. However, the prediction of underwater sand bar evolution remains a challenge.

scholarly journals The Flexible Operation of Coal Power and Its Renewable Integration Potential in China

2019 ◽  
Vol 11 (16) ◽  
pp. 4424 ◽  
Author(s):  
Chunning Na ◽  
Huan Pan ◽  
Yuhong Zhu ◽  
Jiahai Yuan ◽  
Lixia Ding ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Large Scale ◽  
Renewable Integration ◽  
Flexible Resources ◽  
Feasible Option ◽  
Coal Power ◽  
Simulation Results ◽  
Flexible Operation

At present time, China’s power systems face significant challenges in integrating large-scale renewable energy and reducing the curtailed renewable energy. In order to avoid the curtailment of renewable energy, the power systems need significant flexibility requirements in China. In regions where coal is still heavily relied upon for generating electricity, the flexible operations of coal power units will be the most feasible option to face these challenges. The study first focused on the reasons why the flexible operation of existing coal power units would potentially promote the integration of renewable energy in China and then reviewed the impacts on the performance levels of the units. A simple flexibility operation model was constructed to estimate the integration potential with the existing coal power units under several different scenarios. This study’s simulation results revealed that the existing retrofitted coal power units could provide flexibility in the promotion of the integration of renewable energy in a certain extent. However, the integration potential increment of 20% of the rated power for the coal power units was found to be lower than that of 30% of the rated power. Therefore, by considering the performance impacts of the coal power units with low performances in load operations, it was considered to not be economical for those units to operate at lower than 30% of the rated power. It was believed that once the capacity share of the renewable energy had achieved a continuously growing trend, the existing coal power units would fail to meet the flexibility requirements. Therefore, it was recommended in this study that other flexible resources should be deployed in the power systems for the purpose of reducing the curtailment of renewable energy. Furthermore, based on this study’s obtained evidence, in order to realize a power system with high proportions of renewable energy, China should strive to establish a power system with adequate flexible resources in the future.

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