canopy size
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2022 ◽  
pp. 22-26
Author(s):  
T. M. DeJong

Abstract Trees are, by definition, the tallest land plants. To grow tall over multiple years they must solve several problems: structural strength; carbohydrate and nutrient storage capacity to survive and regrow after periods of stress; and conductive capacity for water, carbohydrates and nutrients must be increased/renewed over time to keep pace with increases in canopy size. Additionally, apical meristems must be capable of surviving through periods of stress (especially over winter or during drought). Structural strength, storage capacity and water, carbohydrate and nutrient conductive capacity are provided by cells derived from a sheath of meristematic cells (vascular cambium) that surround the body of trees (shoots, stems, branches, trunk, perennial roots). This chapter describes the structure of fruit trees.


2021 ◽  
Vol 5 (3) ◽  
pp. 072-075
Author(s):  
Abobatta Waleed Fouad

The main purpose of a High-intensity cultivation system is to maximize the yield crop per area unit through planting more trees, exploiting efficient use of different resources. There are different factors that affect high-intensity cultivation that include Land-cost, planting spaces, tree size, Rootstock, and Practice management. Meanwhile, the adoption of High-intensity cultivation to control canopy size, by using modern management practices is very crucial to get more yields in the early stages of the orchard besides simplicity in its management and increase the farmers’ net profit. In addition, High-density cultivation use in different fruit crops like olive, mango, orange, mandarin, Apple, and cherry. Numerous benefits of intensive fruit cultivation include increase fruit yield per unit area, improving use efficiency of natural resources e.g. soil, light, water, and nutrients, enhancing fruit quality, improving soil properties and rising levels of organic carbon and nutrients in plant tissues …etc. In addition, it is very effective in acid lime soil and achieves high income for the farmers.


2021 ◽  
Vol 71 (5) ◽  
pp. 594-601
Author(s):  
Mahendra Pratap ◽  
A. K. Agrawal ◽  
S. C. Sati ◽  
A. K. Saxena

This paper discusses the design of a square parachute based on classical approach, computational analysis and experimentation. This parachute will be used to drop directional sonobuoy on the sea to locate and classify the submarines. Design improvements are brought out by providing slits into a solid square canopy of parachute to bring in more stability and minimum drift during descend. Specifically, the effect of upstream sonobuoy, RANS model, suspension line length, canopy size and slit size in flow structure were considered. The predicted drag coefficients obtained from CFD for square canopy with slit-cuts compared with the results of wind tunnel experiment and found that the increase in the suspension-line length and/or of the surface area of the parachute canopy helps in better stability and results in the minimum drag loss.


2021 ◽  
Author(s):  
changshun wang ◽  
huiqing wang ◽  
wei wang ◽  
cunzhu liang ◽  
huamin liu ◽  
...  

Abstract Background: The aim of this study was to identify and explore the community formation mechanism of R. soongarica in the eastern Mongolian Plateau grassland. The experimental site was located in an ancient lake basin with saline soil in a desert steppe. Results: Soil conductivity of R. soongarica was significantly higher than that of the two herbs, S. glareosa and A. polyrhizum, at all soil depths (P ≤ 0.001). The daily salt secretion rate ranged from 1% to 2% of the fresh leaf weight in the different communities and increased with increased soil conductivity. With increased canopy size of R. soongarica, the distance between the shrubs and herbs also increased. The correlation between the R. soongarica canopy diameter and the distance to the nearest S. glareosa (R2 = 0.4065; P < 0.05) was higher than that to the nearest A. polyrhizum (R2 = 0.1256; P < 0.05). The growth of the three species was not salt-dependent; however, R. soongarica was significantly more salt-tolerant than the two herbs. The two herbs significantly limited the growth of R. soongarica seedlings at low soil conductivity (≤ 600 µS/cm), but not at high soil conductivity (≥ 1000 µS/cm). Conclusions: Salt secretion by R. soongarica leaves results in the formation of a “saline island,” which leads to soil conductivity increasing significantly under the canopy of R. soongarica. This increase in soil conductivity of the saline island effectively reduces the interspecies competition advantage of the two herbs. This highlights the competitiveness of R. soongarica in salt-stressed environments and facilitates the establishment of this desert shrub in saline regions on the desert steppe.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 704
Author(s):  
Theekshana C. Jayalath ◽  
Marc W. van Iersel

Vertical farming is increasingly popular due to high yields obtained from a small land area. However, the energy cost associated with lighting of vertical farms is high. To reduce this cost, more energy efficient (biomass/energy use) crops are required. To understand how efficiently crops use light energy to produce biomass, we determined the morphological and physiological differences between mizuna (Brassica rapa var. japonica) and lettuce (Lactuca sativa ‘Green Salad Bowl’). To do so, we measured the projected canopy size (PCS, a morphological measure) of the plants throughout the growing cycle to determine the total amount of incident light the plants received. Total incident light was used together with the final dry weight to calculate the light use efficiency (LUE, g of dry weight/mol of incident light), a physiological measure. Plants were grown under six photosynthetic photon flux densities (PPFD), from 50 to 425 µmol m–2 s–1, for 16 h d–1. Mizuna and lettuce were harvested 27 and 28 days after seeding, respectively. Mizuna had greater dry weight than lettuce (P < 0.0001), especially at higher PPFDs (PPFD ≥ 125 µmol m–2 s–1), partly because of differences in the projected canopy size (PCS). Mizuna had greater PCS than lettuce at PPFDs ≥ 125 µmol m–2 s–1 and therefore, the total incident light over the growing period was also greater. Mizuna also had a higher LUE than lettuce at all six PPFDs. This difference in LUE was associated with higher chlorophyll content index and higher quantum yield of photosystem II in mizuna. The combined effects of these two factors resulted in higher photosynthetic rates in mizuna than in lettuce (P = 0.01). In conclusion, the faster growth of mizuna is the result of both a larger PCS and higher LUE compared to lettuce. Understanding the basic determinants of crop growth is important when screening for rapidly growing crops and increasing the efficiency of vertical farms.


2021 ◽  
Vol 14 (1) ◽  
pp. 71-80
Author(s):  
Rendy Bayu Aditya ◽  
Muhammad Ulul Lizamun Ningam

The study aims to measure the greenness of an Indonesia city using tree canopy cover data. Rapid physical development brings impacts to the loss of urban trees, which leads to the increase of flooding risk, local temperature and pollution level. To address the issues, a baseline assessment of urban tree canopy existence is necessary as inputs for effective urban environmental management policies. The methods used in this research include 1) remote sensing and spatial analysis, and 2) simple quantitative analysis. Furthermore, three indicators are used in assessing the greenness, including 1) size of the canopy, 2) canopy cover percentage, and 3) canopy per capita. The results found that the city of Yogyakarta has a low level of greenness based on the canopy size in which covers only 467.37 ha or 14.38% of the total area. The second finding is Yogyakarta has an unequal distribution of canopy cover percentage in each district (kecamatan). The third finding is Yogyakarta City has a canopy per capita rate of 10.93 sq m/person. This number is below the UN recommendation of 15sq m / person. It indicates that residents have poor access to urban greenery. Additionally, the article discusses that the three indicators used have strength and weakness in measuring the level of greenness. Therefore, the assessment objectives must be taken into account. We recommend the use of each indicator as follows: 1) the canopy size is used as an initial inventory of the existence and distribution of the canopy, 2) the canopy cover percentage canopy percentage for measuring and comparing the level of greenness spatially and visually between areas, 3) the canopy per capita is used to measure the possibility of access and interaction of residents with the presence of a tree canopy. Cities’ authority can use the information to measure the achievement of SDGs number 11, 13, or 15.


2021 ◽  
Vol 14 (1) ◽  
pp. 71-80
Author(s):  
Rendy Bayu Aditya ◽  
Muhammad Ulul Lizamun Ningam

The study aims to measure the greenness of an Indonesia city using tree canopy cover data. Rapid physical development brings impacts to the loss of urban trees, which leads to the increase of flooding risk, local temperature and pollution level. To address the issues, a baseline assessment of urban tree canopy existence is necessary as inputs for effective urban environmental management policies. The methods used in this research include 1) remote sensing and spatial analysis, and 2) simple quantitative analysis. Furthermore, three indicators are used in assessing the greenness, including 1) size of the canopy, 2) canopy cover percentage, and 3) canopy per capita. The results found that the city of Yogyakarta has a low level of greenness based on the canopy size in which covers only 467.37 ha or 14.38% of the total area. The second finding is Yogyakarta has an unequal distribution of canopy cover percentage in each district (kecamatan). The third finding is Yogyakarta City has a canopy per capita rate of 10.93 sq m/person. This number is below the UN recommendation of 15sq m / person. It indicates that residents have poor access to urban greenery. Additionally, the article discusses that the three indicators used have strength and weakness in measuring the level of greenness. Therefore, the assessment objectives must be taken into account. We recommend the use of each indicator as follows: 1) the canopy size is used as an initial inventory of the existence and distribution of the canopy, 2) the canopy cover percentage canopy percentage for measuring and comparing the level of greenness spatially and visually between areas, 3) the canopy per capita is used to measure the possibility of access and interaction of residents with the presence of a tree canopy. Cities’ authority can use the information to measure the achievement of SDGs number 11, 13, or 15.


2021 ◽  
Vol 9 (1) ◽  
pp. 5-11
Author(s):  
Srinivasa N ◽  
◽  
Subhash Chander ◽  
Padala Vinod Kumar ◽  
◽  
...  

The effect of elevated CO2 (570±25ppm) on the brown plant hopper (BPH) population, rice yield parameters, and efficacy of buprofezin (0.05%) in terms of spray volume was studied in an open top chamber (OTCs) during rainy season 2017 and 2018. The pest population was observed to be higher during 2017 compared to the rainy season of 2018. Under elevated CO2, rice plants had more vegetative tillers (18%) and reproductive tillers (22.1%), but there was a decrease in 1000-seed weight (11.2%), seed number per panicle (3.91%), and grain yield (18.8%) in comparison to ambient CO2 grown rice plants. The spray volumes of 700, 600, 500, and 400 l/ha each caused higher BPH mortality under ambient CO2 compared to elevated CO2. A spray volume of 500 l/ha did not prove as effective under elevated CO2 as under ambient CO2. Lower efficacy of spray volume of 500 l/ha under elevated CO2 could be ascribed to higher canopy size under elevated CO2 due to higher tillering. Increased crop canopy size under elevated CO2 may thus require higher spray volume to ensure proper coverage. Results of the study suggested a need to revise spray volume recommendations to facilitate effective management of BPH under climate change.


2021 ◽  
Vol 13 (5) ◽  
pp. 855
Author(s):  
Pedro C. Towers ◽  
Carlos Poblete-Echeverría

Accurate quantification of the spatial variation of canopy size is crucial for vineyard management in the context of Precision Viticulture. Biophysical parameters associated with canopy size, such as Leaf Area Index (LAI), can be estimated from Vegetation Indices (VI) such as the Normalized Difference Vegetation Index (NDVI), but in Vertical-Shoot-Positioned (VSP) vineyards, common satellite, or aerial imagery with moderate-resolution capture information at nadir of pixels whose values are a mix of canopy, sunlit soil, and shaded soil fractions and their respective spectral signatures. VI values for each fraction are considerably different. On a VSP vineyard, the illumination direction for each specific row orientation depends on the relative position of sun and earth. Respective proportions of shaded and sunlit soil fractions change as a function of solar elevation and azimuth, but canopy fraction is independent of these variations. The focus of this study is the interaction of illumination direction with canopy orientation, and the corresponding effect on integrated NDVI. The results confirm that factors that intervene in determining the direction of illumination on a VSP will alter the integrated NDVI value. Shading induced considerable changes in the NDVI proportions affecting the final integrated NDVI value. However, the effect of shading decreases as the row orientation approaches the solar path. Therefore, models of biophysical parameters using moderate-resolution imagery should consider corrections for variations caused by factors affecting the angle of illumination to provide more general solutions that may enable canopy data to be obtained from mixed, integrated vine NDVI.


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