scholarly journals Early-Season Mapping of Winter Crops Using Sentinel-2 Optical Imagery

2021 ◽  
Vol 13 (19) ◽  
pp. 3822
Author(s):  
Haifeng Tian ◽  
Yongjiu Wang ◽  
Ting Chen ◽  
Lijun Zhang ◽  
Yaochen Qin
Keyword(s):  
Winter Wheat ◽  
Growth Stage ◽  
Early Growth ◽  
Classification Model ◽  
Free Access ◽  
Early Growth Stage ◽  
Winter Canola ◽  
Winter Crops ◽  
Data Source ◽  
Sentinel 2

Sentinel-2 imagery is an unprecedented data source with high spatial, spectral and temporal resolution in addition to free access. The objective of this paper was to evaluate the potential of using Sentinel-2 data to map winter crops in the early growth stage. Analysis of three winter crop types—winter garlic, winter canola and winter wheat—was carried out in two agricultural regions of China. We analysed the spectral characteristics and vegetation index profiles of these crops in the early growth stage and other land cover types based on Sentinel-2 images. A decision tree classification model was built to distinguish the crops based on these data. The results demonstrate that winter garlic and winter wheat can be distinguished four months before harvest, while winter canola can be distinguished two months before harvest. The overall classification accuracy was 96.62% with a kappa coefficient of 0.95. Therefore, Sentinel-2 images can be used to accurately identify these winter crops in the early growth stage, making them an important data source in the field of agricultural remote sensing.

scholarly journals Temporal Dynamics of Microcystins In Two Reservoirs With Different Trophic Status During The Early Growth Stage of Cyanobacteria

2021 ◽  
Author(s):  
Qingju Xue ◽  
Ming Kong ◽  
Liqiang Xie ◽  
Tong Li ◽  
Mengna Liao ◽  
...  
Keyword(s):  
Growth Stage ◽  
Trophic Status ◽  
Temporal Dynamics ◽  
Influence Factors ◽  
Environmental Parameters ◽  
Early Growth ◽  
Cyanobacterial Blooms ◽  
Organic Matters ◽  
Early Growth Stage ◽  
Density And Biomass

Abstract Harmful cyanobacterial blooms are increasing in frequency and severity, which makes their toxic secondary metabolites of microcystins (MCs) have been widely studied, especially in their distribution and influence factors in different habitats. However, the distribution of MCs on the early growth stage of harmful cyanobacteria and its influence factors and risks are still largely unknown. Thus, in the present study, two reservoirs (Lutian Reservoir and Lake Haitang) with different trophic status in China have been studied weekly from March to May in 2018, when the cyanobacteria communities were just in the early growth stage, to investigate the variation of MCs concentration and the relationships between MCs and environmental parameters. During the investigation, Lutian Reservoir and Lake Haitang were found to be mesotrophic and light eutrophic, respectively. In Lutian Reservoir, the concentration of EMCs was obviously higher than that of IMCs with a mean value of 0.323 and 0.264 μg/L, respectively. Meanwhile, the concentration of EMCs also fluctuated more sharply than that of IMCs. Congeners of IMC-YR and EMC-LR were respectively dominant in total concentrations of IMCs and EMCs. Unsurprisingly, in Lake Haitang, the concentrations of IMC and EMC were both significantly higher than that in Lutian Reservoir with a mean concentration of 0.482 and 0.472 μg/L, respectively. Differently, the concentration of MC-YR was dominant in both IMCs and EMCs, followed by MC-LR. In correlation analysis, the IMCs were significantly and positively correlated with the density and biomass of phytoplankton phyla and potential MCs-producing cyanobacteria and the parameters of water temperature (WT), nutrients and organic matters. Similar results were also observed for EMCs. While the different variation of MCs in two reservoirs might be primarily caused by the differences in WT, nutrients (especially phosphorus), organic matters and the composition of MCs-producing cyanobacteria. In addition, the coexistence of the dominant species of Pseudoanabaena sp., which can produce taste-and-odor compound of 2-methylisoborneol (2-MIB), might have significant impacts on the concentration and toxicity of MCs. Our results suggested that the risks posed by MCs at the early growth stage of cyanobacteria should also deserve our attentions, especially in mesotrophic water bodies.

scholarly journals Growth, Development, and Chemical Constituents of Edible Ice Plant (Mesembryanthemum crystallinum L.) Produced under Combinations of Light-emitting Diode Lights

HortScience ◽  
2018 ◽  
Vol 53 (6) ◽  
pp. 865-874 ◽  
Author(s):  
Thitipat Weeplian ◽  
Tsair-Bor Yen ◽  
Yunn-Shy Ho
Keyword(s):  
Vegetative Growth ◽  
Growth Stage ◽  
Chemical Constituents ◽  
Early Growth ◽  
Mesembryanthemum Crystallinum ◽  
Light Spectrum ◽  
Light Emitting ◽  
Early Growth Stage ◽  
Light Spectra ◽  
Late Growth

To investigate the effects of light treatments on the growth morphology and chemical constituents of Mesembryanthemum crystallinum L. plants, red (R), blue (B), far red (Fr), and white (W) light-emitting diodes (LEDs) were configured to provide different combinations of light spectra and photosynthetic photon flux densities (PPFDs). In Expt. 1, five light spectra of red/white (RW), red/white/far red (RWFr), red/white/high-intensity far red (RWFrD), red/blue (RB), and red/blue/far red (RBFr) were set up in two 3-layered racks with circulating hydroponic systems. In each light spectrum treatment, the distance between the LED lamps and the transplanting board was regulated to provide low PPFD and high PPFD treatments. In Expt. 2, the effect of Fr was further investigated in plants in the early and late growth stages. RWFr light was modified by covering the Fr lamps to become red/white without far red (RW−Fr) light during the early growth stage, and then removing the covers to provide the Fr spectrum red/white with far red (RW+Fr) during the later growth stage. This study suggested that high PPFD was not beneficial for promoting plant growth in any light spectrum treatment. Among light spectrum treatments at a PPFD of 215 ± 15 μmol·m−2·s−1, RW light produced higher vegetative growth. In the late growth stage, RW and RB combined with Fr light promoted reproductive growth, antioxidant activities, and secondary compounds, such as phenolic compounds, pinitol accumulation, and betacyanins. Therefore, RW (227 μmol·m−2·s−1), RW−Fr (162 μmol·m−2·s−1), and RB (162 μmol·m−2·s−1) are suggested for the early growth stage to promote vegetative growth. Then additional Fr light can be applied in addition to RW for secondary metabolite induction in the late growth stage.

scholarly journals Exploitation of variability for salinity tolerance in maize hybrids (Zea mays L.) at early growth stage

2016 ◽  
Vol 11 (42) ◽  
pp. 4206-4213 ◽  
Author(s):  
Qayyum Abdul ◽  
Muhammad Saeed Hafiz ◽  
Hanif Mamoona ◽  
Noor Etrat ◽  
Malik Waqas ◽  
...  
Keyword(s):  
Zea Mays ◽  
Salinity Tolerance ◽  
Growth Stage ◽  
Zea Mays L ◽  
Early Growth ◽  
Early Growth Stage ◽  
Maize Hybrids

scholarly journals Garlic and Winter Wheat Identification Based on Active and Passive Satellite Imagery and the Google Earth Engine in Northern China

2020 ◽  
Vol 12 (21) ◽  
pp. 3539
Author(s):  
Haifeng Tian ◽  
Jie Pei ◽  
Jianxi Huang ◽  
Xuecao Li ◽  
Jian Wang ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Winter Wheat ◽  
Satellite Imagery ◽  
Remote Sensing Data ◽  
Northern China ◽  
Google Earth ◽  
Kappa Coefficient ◽  
Landsat 8 ◽  
Winter Crops ◽  
Sentinel 2

Garlic and winter wheat are major economic and grain crops in China, and their boundaries have increased substantially in recent decades. Updated and accurate garlic and winter wheat maps are critical for assessing their impacts on society and the environment. Remote sensing imagery can be used to monitor spatial and temporal changes in croplands such as winter wheat and maize. However, to our knowledge, few studies are focusing on garlic area mapping. Here, we proposed a method for coupling active and passive satellite imagery for the identification of both garlic and winter wheat in Northern China. First, we used passive satellite imagery (Sentinel-2 and Landsat-8 images) to extract winter crops (garlic and winter wheat) with high accuracy. Second, we applied active satellite imagery (Sentinel-1 images) to distinguish garlic from winter wheat. Third, we generated a map of the garlic and winter wheat by coupling the above two classification results. For the evaluation of classification, the overall accuracy was 95.97%, with a kappa coefficient of 0.94 by eighteen validation quadrats (3 km by 3 km). The user’s and producer’s accuracies of garlic are 95.83% and 95.85%, respectively; and for the winter wheat, these two accuracies are 97.20% and 97.45%, respectively. This study provides a practical exploration of targeted crop identification in mixed planting areas using multisource remote sensing data.

Melanosclerites: first North American report of these problematic microfossils and discussion of their affinity

1992 ◽  
Vol 66 (4) ◽  
pp. 563-569 ◽  
Author(s):  
P. B. Cashman
Keyword(s):  
North American ◽  
Growth Stage ◽  
Early Growth ◽  
Junior Synonym ◽  
Early Growth Stage ◽  
The Family ◽  
Strong Resemblance ◽  
Gaspe Peninsula ◽  
Gaspé Peninsula

Melanosclerites are rod-shaped, pseudochitinous microfossils of problematic affinity. They have not been widely studied. The first North American discovery of melanosclerites is here reported; Melanostylus coronifer and Melanosteus acutus (the latter with two subspecies), of Devonian (Late Siegenian) age, were discovered in the Indian Cove Formation of the Upper Gaspé Limestones from the Gaspé Peninsula, Quebec, Canada.These melanosclerites bear a strong resemblance to the modern cubomedusa polyp Carybdea alata and the planula stages of the hydrozoan Pennaria tiarella. They are interpreted as being the embryonic planula and early polyp stages of scyphozoans, cubozoans, and hydrozoans.Consequently, Semenola semen Schallreuter, 1981, is considered an early growth stage of M. acutus anceps and thus a junior synonym; similarly, Eichbaumia incus is a junior synonym of Melanostylus coronifer; while, on the basis of their three-fold symmetry, Orthopelta? femuralis Eller, 1945, and Menola os Schallreuter, 1981, are treated as junior synonyms of Melanofurca neptuni Eisenack, 1963. Melanosclerites could represent the planula and polyp stages of any of the three classes of Cnidaria; therefore, the order Melanoscleritoitidea Eisenack, 1963, and the family Melanoscleritoitidae are here rejected because the supposed family crosses the boundaries of classes. The new subspecific combinations Melanosteus acutus acutus, M. acutus filiformis, and M. acutus anceps are proposed, their diagnoses being emended; the diagnosis of Melanostylus coronifer is also emended.Melanosclerites appear to be strongly facies controlled and thus may have potential for paleoenvironmental and paleogeographical reconstructions.

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