261 research outputs found
Assessment of production zones modelling accuracy based on satellite imaging and yield measurement of selected agriculture plot
ArticleCurrently, remote sensing or yield monitor equipment offer possibilities how to
estimate productivity of the agriculture field. That is why the main aim of this study is to assess
how the latest satellite images from vegetation season and final yield data from combine harvester
can be used to predict yield and to assess site-specific zones productivity. The study is focused
on the accuracy of these systems for the field productivity estimation. The 24.7 ha experimental
field is located near to Vendoli village (the Czech Republic) and it is cultivated by conventional
agricultural practices with emphasis on typical agricultural crops growing in the Czech Republic
(winter wheat, spring barley and winter rape). The results showed that both methods of estimation
can be used for yield prediction. Nevertheless, each of them need specific processing and has
typical limitations
Winter wheat, winter rape and poppy crop growth evaluation with the help of remote and proximal sensing measurements
Monitoring of agricultural crops with the help of remote and proximal sensors during
the growing season plays important role for site-specific management decisions. Winter wheat,
winter rape and poppy are representatives of typical agricultural crops from the family Poacea,
Brassicaceae and Papaveraceae, growing in relative dry area of Rakovník district in the Czech
Republic. Ten Sentinel 2 satellite images acquired during vegetation season of the crops were
downloaded and processed. Crops were monitored with the help of unmanned aerial vehicles
(UAV) equipped with consumer grade Red Green Blue (RGB) camera and multispectral (MS)
MicaSense RedEdge MX camera. In-field variability was assessed by computing RGB-based
vegetation indices Triangular Greenness Index (TGI), Green Leaf Index (GLI) and Visible
Atmospherically Resistant Index (VARI) and commonly used vegetation indices as Normalised
Difference Vegetation Index (NDVI) and Green NDVI (GNDVI). The results derived from
satellite and UAV images were supported with in-situ measurements of hand-held GreenSeeker
and Chlorophyll Meter Content sensors. The study showed the usability of individual vegetation
indices, especially the TGI index for chlorophyll content estimation, and VARI index for green
vegetation fraction detection and leaf area index estimation, in comparison with selected handheld devices. The results showed as well that leaf properties and canopy structure of typical
characteristics of selected families can significantly influence the spectral response of the crops
detected in different phenological stages
Comparing RGB - based vegetation indices from UAV imageries to estimate hops canopy area
Remote estimation of hops plants in hop gardens is imperative in field of precision
agriculture, because of precise imaging of hop garden structure. Monitoring of hop plant volume
and area can help to predict the condition and yield of hops. In this study, two unmanned aerial
vehicles (UAV) – eBee X senseFly UAV equipped with Red Green Blue (RGB) S.O.D.A. camera
and Vertical Take-Off Landing (VTOL) UAV FireFly6 Pro by BirdsEyeView Aerobotics
equipped with MicaSense RedEdge MX camera were used to acquire images of hop garden at
phenology stage maturity of cones (24 th July) before harvest. Seven commonly used RGB
vegetation indices (VI) were derived from these RGB and multispectral (MS) images after
photogrammetric pre-processing and orthophoto mosaic extraction using Pix4Dmapper software.
Vegetation Indices as the Green Percentage Index (G%), Excess of Green Index (ExGreen),
Green Leaf Index (GLI), Visible Atmospherically Resistant Index (VARI), Red Green Blue
Vegetation Index (RGBVI), Normalised Green Red Difference Index (NGRDI) and Triangular
Greenness Index (TGI) were derived from both data sets. Binary model from each of VI was
derived and threshold value for green vegetation was set. The results showed significant
differences in hop plant area based on the specifications of cameras, especially wavelengths
centres, and design and flight parameters of both UAV types. The comparison of various indices
showed, that ExG and TGI indices has the highest congruity of estimated vegetation indices in
hop garden canopy area for both used cameras. Further processing by Fuzzy Overlay tool proved
high accuracy in green canopy area estimation for ExG and TGI vegetation indices
Review of invasive grapevine aphid, Aphis illinoisensis Shimer, and native parasitoids in the Mediterranean (Hemiptera, Aphididae; Hymenoptera, Braconidae, Aphidiinae)
A summary of the study of Aphis illinoisensis Shimer on grapes, Vitis vinifera in the Mediterranean area brings references and new findings on its distribution in Crete/Greece, Turkey, Northern Cyprus, Malta, Israel, Montenegro, Tunisia, Algeria and Libya. Parasitoids of A. illinoisensis were only occasionally found (Aphidius matricariae Hal. - Cyprus, Turkey, Greece; Aphidius colemani Viereck - Libya; Lysiphlebus testaceipes Cress. - Algeria). Of the native species, i.e. A. colemani, and others similar to the native species, L. testaceipes seem to be a promising biocontrol agent within the framework of an ecologically friendly management in the area. Given the evidence of its expansion, A. illinoisensis is expected to expand further in several directions from the recently documented invaded area to all the grape-growing areas of the Mediterranean and even those of South-Eastern and Central Europe
Soil Food Web Changes during Spontaneous Succession at Post Mining Sites: A Possible Ecosystem Engineering Effect on Food Web Organization?
Lagomorphs (a group that consists of pikas, hares, rabbits and allies) are notable for their conservative morphology retained for most of their over 50 million years evolutionary history. On the other hand, their remarkable morphological uniformity partly stems from a considerable number of homoplasies in cranial and dental structures that hamper phylogenetic analyses. The premolar foramen, an opening in the palate of lagomorphs, has been characterized as an important synapomorphy of one clade, Ochotonidae (pikas). Within Lagomorpha, however, its phylogenetic distribution is much wider, the foramen being present not only in all ochotonids but also in leporids and stem taxa; its morphology and incidence also varies considerably across the order, even intraspecifically. In this study, we provide a broad survey of the taxonomic distribution of the premolar foramen in extant and fossil Lagomorpha and describe in detail the morphological variation of this character within the group. Micro-computed tomography was used to examine the hard palate and infraorbital groove morphology in Poelagus (Leporidae) and Ochotona. Scans revealed the course and contacts of the canal behind the premolar foramen and structural differences between the two crown clades. We propose that the premolar foramen has evolved independently in several lineages of Lagomorpha, and we discuss development and function of this foramen in the lagomorph skull. This study shows the importance of comprehensive studies on phylogenetically informative non-dental characters in Lagomorpha
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