A Modeling Approach to Simulate Effects of Intercropping and Interspecific Competition in Arable Crops

2010 ◽  
Vol 1 (4) ◽  
pp. 44-65 ◽  
Author(s):  
Heike Knörzer ◽  
Simone Graeff-Hönninger ◽  
Bettina U. Müller ◽  
Hans-Peter Piepho ◽  
Wilhelm Claupein
Keyword(s):  
Solar Radiation ◽  
Soil Temperature ◽  
Interspecific Competition ◽  
Neighborhood Effects ◽  
Individual Growth ◽  
Arable Crops ◽  
Beneficial Effects ◽  
Modeling Approaches ◽  
Use Efficiency ◽  
And Performance

Interspecific competition between species influences their individual growth and performance. Neighborhood effects become especially important in intercropping systems, and modeling approaches could be a useful tool to simulate plant growth under different environmental conditions to help identify appropriate combinations of different crops while managing competition. This study gives an overview of different competition models and their underlying modeling approaches. To model intercropping in terms of neighbouring effects in the context of field boundary cultivation, a new model approach was developed and integrated into the DSSAT model. The results indicate the possibility of simulating general competition and beneficial effects due to different incoming solar radiation and soil temperature in a winter wheat/maize intercropping system. Considering more than the competition factors is important, that is, sunlight, due to changed solar radiation alone not explaining yield differences in all cases. For example, intercropped maize could compensate low radiation due to its high radiation use efficiency. Wheat benefited from the increased solar radiation, but even more from the increased soil temperature.

A Modeling Approach to Simulate Effects of Intercropping and Interspecific Competition in Arable Crops

2012 ◽  
pp. 160-181
Author(s):  
Heike Knörzer ◽  
Simone Graeff-Hönninger ◽  
Bettina U. Müller ◽  
Hans-Peter Piepho ◽  
Wilhelm Claupein
Keyword(s):  
Solar Radiation ◽  
Soil Temperature ◽  
Interspecific Competition ◽  
Neighborhood Effects ◽  
Individual Growth ◽  
Beneficial Effects ◽  
Modeling Approaches ◽  
Use Efficiency ◽  
And Performance ◽  
Radiation Use

Interspecific competition between species influences their individual growth and performance. Neighborhood effects become especially important in intercropping systems, and modeling approaches could be a useful tool to simulate plant growth under different environmental conditions to help identify appropriate combinations of different crops while managing competition. This study gives an overview of different competition models and their underlying modeling approaches. To model intercropping in terms of neighbouring effects in the context of field boundary cultivation, a new model approach was developed and integrated into the DSSAT model. The results indicate the possibility of simulating general competition and beneficial effects due to different incoming solar radiation and soil temperature in a winter wheat/maize intercropping system. Considering more than the competition factors is important, that is, sunlight, due to changed solar radiation alone not explaining yield differences in all cases. For example, intercropped maize could compensate low radiation due to its high radiation use efficiency. Wheat benefited from the increased solar radiation, but even more from the increased soil temperature.

Contrasting yield formation characteristics in two super-rice hybrids that differ in growth duration

2021 ◽  
pp. 1-10
Author(s):  
Min Huang ◽  
Zui Tao ◽  
Tao Lei ◽  
Fangbo Cao ◽  
Jiana Chen ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Biomass Production ◽  
Field Experiments ◽  
Crop Improvement ◽  
Total Biomass ◽  
Growth Duration ◽  
Area Index ◽  
Rice Hybrid ◽  
Use Efficiency ◽  
Yield Formation

Summary The development of high-yielding, short-duration super-rice hybrids is important for ensuring food security in China where multiple cropping is widely practiced and large-scale farming has gradually emerged. In this study, field experiments were conducted over 3 years to identify the yield formation characteristics in the shorter-duration (∼120 days) super-rice hybrid ‘Guiliangyou 2’ (G2) by comparing it with the longer-duration (∼130 days) super-rice hybrid ‘Y-liangyou 1’ (Y1). The results showed that G2 had a shorter pre-heading growth duration and consequently a shorter total growth duration compared to Y1. Compared to Y1, G2 had lower total biomass production that resulted from lower daily solar radiation, apparent radiation use efficiency (RUE), crop growth rate (CGR), and biomass production during the pre-heading period, but the grain yield was not significantly lower than that of Y1 because it was compensated for by the higher harvest index that resulted from slower leaf senescence (i.e., slower decline in leaf area index during the post-heading period) and higher RUE, CGR, and biomass production during the post-heading period. Our findings suggest that it is feasible to reduce the dependence of yield formation on growth duration to a certain extent in rice by increasing the use efficiency of solar radiation through crop improvement and also highlight the need for a greater fundamental understanding of the physiological processes involved in the higher use efficiency of solar radiation in super-rice hybrids.

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 Battery lifetime prediction and performance assessment of different modeling approaches

iScience ◽  
2021 ◽  
Vol 24 (2) ◽  
pp. 102060
Author(s):  
Md Sazzad Hosen ◽  
Joris Jaguemont ◽  
Joeri Van Mierlo ◽  
Maitane Berecibar
Keyword(s):  
Performance Assessment ◽  
Lifetime Prediction ◽  
Battery Lifetime ◽  
Modeling Approaches ◽  
And Performance

scholarly journals Protective Netting Improves Leaf-level Photosynthetic Light Use Efficiency in ‘Honeycrisp’ Apple Under Heat Stress

HortScience ◽  
2018 ◽  
Vol 53 (10) ◽  
pp. 1416-1422 ◽  
Author(s):  
Giverson Mupambi ◽  
Stefano Musacchi ◽  
Sara Serra ◽  
Lee A. Kalcsits ◽  
Desmond R. Layne ◽  
...  
Keyword(s):  
Heat Stress ◽  
Solar Radiation ◽  
Leaf Gas Exchange ◽  
Growing Season ◽  
High Light ◽  
Weather Data ◽  
Light Use Efficiency ◽  
Ambient Temperatures ◽  
Leaf Level ◽  
Use Efficiency

Globally, apple production often occurs in semiarid climates characterized by high summer temperatures and solar radiation. Heat stress events occur regularly during the growing season in these regions. For example, in the semiarid eastern half of Washington State, historic weather data show that, on average, 33% of the days during the growing season exceed 30 °C. To mediate some of the effects of heat stress, protective netting (PN) can be used to reduce the occurrence of fruit sunburn. However, the impacts of reduced solar radiation in a high light environment on light-use efficiency and photosynthesis are poorly understood. We sought to understand the ecophysiological response of apple (Malus domestica Borkh. cv. Honeycrisp) under blue photoselective PN during days with low (26.6 °C), moderate (33.7 °C), or high (38.1 °C) ambient temperatures. Two treatments were evaluated; an uncovered control and blue photoselective PN. Maximum photochemical efficiency of PSII, or photosystem II (Fv/Fm) was significantly greater at all measurement times under blue photoselective PN compared with the control on days with high ambient temperatures. Fv/Fm dropped below 0.79, which is considered the threshold for stress, at 1000 hr in the control and at 1200 hr under blue photoselective PN on a day with high ambient temperature. On days with low or moderate ambient temperatures, Fv/Fm was significantly greater under blue photoselective PN at 1400 hr, which coincided with the peak in solar radiation. ‘Honeycrisp’ apple exhibited dynamic photoinhibition as shown by the diurnal decline in Fv/Fm. Quantum photosynthetic yield of PSII (ΦPSII) was also generally greater under blue photoselective PN compared with the control for days with moderate or high ambient temperatures. Photochemical reflectance index (ΔPRI), the difference in reflectance between a stress-responsive and nonstress-responsive wavelength, was greater under PN compared with the control on the day with high ambient temperatures, with no differences observed under low or moderate ambient temperatures. Leaf gas exchange did not show noticeable improvement under blue photoselective netting when compared with the control despite the improvement in leaf-level photosynthetic light use efficiency. In conclusion, PN reduced incoming solar radiation, improved leaf-level photosynthetic light use efficiency, and reduced the symptoms of photoinhibition in a high-light, arid environment.

scholarly journals Biodegradable mulch controls weeds and increases water use efficiency in lettuce crops

2021 ◽  
Vol 39 (3) ◽  
pp. 330-334
Author(s):  
Agnaldo Roberto de J Freitas ◽  
Francisco Claudio L de Freitas ◽  
Caetano Marciano de Souza ◽  
Fabio T Delazari ◽  
Paulo Geraldo Berger ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Water Use Efficiency ◽  
Water Use ◽  
Soil Cover ◽  
Polyethylene Film ◽  
Water Volume ◽  
Recycled Paper ◽  
Biodegradable Mulch ◽  
Use Efficiency ◽  
Weed Removal

ABSTRACT Vegetable cultivation requires high water use and weed control. Soil cover using recycled paper, can be an alternative to polyethylene film to reduce weed incidence, soil temperature and increase water use efficiency beyond reduces costs and environmental pollutions. The objective of this study was to evaluate the use of biodegradable mulch in weed management and water use efficiency (WUE) in lettuce crop. The treatments were composed of brown recycled paper (RP), black polyethylene film (PF) and soil without cover with weed removal (WR) and without weed removal (WW). RP and PF were efficient to control weeds. The soil temperature with RP was 8.2 and 2.1ºC lower than with PF and WR, respectively. The lettuce yield with RP was 14.5 and 28.3% higher than WR, and with PF, respectively. The water volume applied with RP was 26.5% lower, and WUE was 55.6% higher compared to WR. Soil cover with recycled paper controlled weeds, reduced soil temperature and water consumption and increased yield and water use efficiency in lettuce crop.

scholarly journals Generative design and performance modeling for relationships between urban built forms, sky opening, solar radiation and energy

2019 ◽  
Vol 158 ◽  
pp. 3994-4002 ◽  
Author(s):  
Soowon Chang ◽  
Nirvik Saha ◽  
Daniel Castro-Lacouture ◽  
Perry Pei-Ju Yang
Keyword(s):  
Solar Radiation ◽  
Performance Modeling ◽  
Generative Design ◽  
And Performance

Top management gender diversity and performance: in search of threshold effects

2020 ◽  
Author(s):  
Yundan Gong ◽  
Sourafel Girma
Keyword(s):  
Business Performance ◽  
Firm Growth ◽  
Gender Diversity ◽  
Threshold Effect ◽  
Business Leaders ◽  
Performance Effect ◽  
Beneficial Effects ◽  
Board Director ◽  
And Performance ◽  
The Impact

Abstract The impact of gender diversity on business performance has been featured prominently on the agenda of many politicians and business leaders in recent years. However, empirical results of the impact of gender diversity on firm performance have been ambiguous. This paper contributes to the literature by using propensity score-based estimation techniques on a large sample of UK firms to analyse the performance effect of appointing a first female board director. We look at financial and non-financial performance indicators and document significant effects on firm growth and labour cost efficiency, but rather fragile ones on accounting returns, such as profitability. We also document evidence of another threshold effect; namely, gender diversity appears to have its highest impact (its ‘ceiling’) when the proportion of female directors is approximately 30%. Carrying out a sensitivity analysis, we conclude that hidden bias must be implausibly high to be able to attribute the beneficial effects of boardroom gender diversity to unmeasured confounding.

scholarly journals Solar radiation use efficiency by soybean under field conditions in the Amazon region

2009 ◽  
Vol 44 (10) ◽  
pp. 1211-1218 ◽  
Author(s):  
Paulo Jorge de Oliveira Ponte de Souza ◽  
Aristides Ribeiro ◽  
Edson José Paulino da Rocha ◽  
José Renato Bouça Farias ◽  
Renata Silva Loureiro ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Leaf Area ◽  
Biomass Production ◽  
Amazon Region ◽  
Field Conditions ◽  
Radiation Use Efficiency ◽  
Area Index ◽  
Natural Field ◽  
Use Efficiency ◽  
Radiation Use

The objective of this work was to evaluate the efficiency of soybean (Glycine max) in intercepting and using solar radiation under natural field conditions, in the Amazon region, Brazil. The meteorological data and the values of soybean growth and leaf area were obtained from an agrometeorological experiment carried out in Paragominas, Pará state, during 2007 and 2008. The radiation use efficiency (RUE) was obtained from the ratio between the above-ground biomass production and the intercepted photosynthetically active radiation (PAR) accumulated to 99 and 95 days after sowing, in 2007 and 2008, respectively. Climatic conditions during the experiment were very distinct, with reduction in rainfall in 2007, which began during the soybean mid-cycle, due to the El Niño phenomenon. An important reduction in the leaf area index and biomass production was observed during 2007. Under natural field conditions in the Amazon region, the values of RUE were 1.46 and 1.99 g MJ-1 PAR in the 2007 and 2008 experiments, respectively. The probable reason for the differences found between these years might be associated to the water restriction in 2007 coupled with the higher air temperature and vapor pressure deficit, and also to the increase in the fraction of diffuse radiation that reached the land surface in 2008.

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