High-resolution UAV imagery for field olive (Olea europaea L.) phenotyping

Remote sensing techniques based on images acquired from unmanned aerial vehicles (UAVs) could represent an effective tool to speed up the data acquisition process in phenotyping trials and, consequently, to reduce the time and cost of the field work. In this study, we assessed the ability of a UAV equipped with RGB-NIR cameras in highlighting differences in geometrical and spectral canopy characteristics between eight olive cultivars planted at different planting distances in a hedgerow olive orchard. The relationships between measured and estimated canopy height, projected canopy area and canopy volume were linear regardless of the different cultivars and planting distances (RMSE of 0.12 m, 0.44m2 and 0.68m3, respectively). Agood relationship (R2 = 0.95) was found between the pruning mass material weighted on the ground and its volume estimated by aerial images. NDVI measured in February 2019 was related to fruit yield per tree measured in November 2018, whereas no relationships were observed with the fruit yield measured in November 2019 due to abiotic and biotic stresses that occurred before harvest. These results confirm the reliability of UAV imagery and structure from motion techniques in estimating the olive geometrical canopy characteristics and suggest further potential applications of UAVs in early discrimination of yield efficiency between different cultivars and in estimating the pruning material volume

Physiological changes induced by either pre- or post-veraison deficit irrigation in 'Merlot' vines grafted on two different rootstocks

Reduced summer precipitations and higher evapotranspiration due to elevated temperatures are expected to enhance the impact of water deficit in modern viticulture. We investigated the effect of the timing of deficit irrigation on vine growth, water relations, yield and grape composition in 'Merlot' vines grafted on 1103P or SO4. In both years we did not measure any differences between rootstocks in stem water potential (SWP). Vegetative growth was decreased by the restriction of irrigation between fruit set and veraison. Stomatal conductance (gs) was affected by irrigation, but not by the rootstock. During the pre-veraison period there was a clear inverse relationship between gs and SWP. The leaf non photochemical quenching readily responded to the stress imposed on 1103P rootstock. Vines subjected to water deficit between fruit set and veraison produced smaller berries than well irrigated ones, whereas deficit applied after veraison determined about 10 % differences in berry weight. The highest and lowest values of pH and TA were measured in berries from pre-veraison deficit irrigated vines grafted on both 1103P and SO4, respectively

Wideband filter using meta material at THz frequency

Wideband filtering application using ceramic meta material is reported in this work. Reflective properties of both SNG and DNG, glass and ceramic materials are presented. Simulation results for both structures predict the wide reflected band is found at Terahertz frequency pertaining to above structures. Also non linear variation of “width of the reflected band” is found with varying the thickness of meta material structure

Estimating biophysical and geometrical parameters of grapevine canopies ('Sangiovese') by an unmanned aerial vehicle (UAV) and VIS-NIR cameras

Three zones of different vine vigour were identified in a mature vineyard (Vitis vinifera 'Sangiovese') to test the potential of the Visible-Near Infrared (VIS-NIR) spectral information acquired from an unmanned aerial vehicles (UAV) in estimating the leaf area index (LAI), leaf chlorophyll, pruning weight, canopy height and canopy volume of grapevines. A significant linear correlation between the normalized differential vegetation index (NDVI) and LAI or between NDVI and leaf chlorophyll was found at day of the year (DOY) 162 and 190, whereas in August the relationship between NDVI and leaf chlorophyll was less evident. The canopy volume of low-vigour (LV) vines was 35 and 45 % of the high-vigour (HV) and medium-vigour (MV) ones, respectively. The pruning weight was linearly correlated with NDVI values of each vigour cohort. A good correlation between the measured canopy volume and UAV-estimated one as well as between measured and estimated canopy height was found. Our results indicated that the combined use of VIS-NIR cameras and UAV is a rapid and reliable technique to determine canopy structure and LAI of grapevine

Autonomous mowing and turf-type bermudagrass as innovations for an environment-friendly floor management of a vineyard in coastal tuscany

The establishment of permanent cover crops is becoming a common practice in vineyard floor management. Turfgrass science may provide species and techniques with a high potential for improving the sustainability of vineyard floor management. Based on this assumption, an experiment was carried out during 2018 and 2019 at the Donna Olimpia Vineyard, Bolgheri, Italy. The trial aimed at comparing an innovative floor management system based on a turf-type cultivar of bermudagrass mown with an autonomous mower with a conventional floor management system. Ground cover percentage, energy consumption, CO2 emissions, grapevine water status, leaf nitrogen content, fruit yield and must composition have been assessed in order to perform the comparison. The innovative vineyard floor management produced an almost complete ground cover (98%) at the end of the second growing season, with the resident species reduced to a small percentage (4%). Resident species growing under-trellis were efficiently controlled without herbicide applications. A lower primary energy consumption and a reduction in CO2 emissions were observed for the innovative management system compared to the conventional management system. Grapevine water status, leaf chlorophyll content, soil–plant analyses development (SPAD), fruit yields and must composition were similar between the different soil management systems. Based on results obtained in this trial, turf-type bermudagrass and innovative mowing machines may contribute to enhance the sustainability of vineyard floor management

Phase transition close to room temperature in BiFeO3 thin films

BiFeO3 (BFO) multiferroic oxide has a complex phase diagram that can be mapped by appropriately substrate-induced strain in epitaxial films. By using Raman spectroscopy, we conclusively show that films of the so-called supertetragonal T-BFO phase, stabilized under compressive strain, displays a reversible temperature-induced phase transition at about 100\circ, thus close to room temperature.Comment: accepted in J. Phys.: Condens. Matter (Fast Track Communication

Ultrasonic velocity and allied acoustical parameters of 2, 4-dinitrophenyl hydrazine based Schiff base in DMSO

1108-1112Novel 2, 4-dinitrophenyl hydrazine based Schiff bases (L1-L3) has been successfully synthesized and characterized. The ultrasonic velocity (C) and density (ρ) has been measured for the synthesized Schiff bases with DMSO (Dimethyl sulfoxide) solvents at 300 K. Using these experimental data ultrasonic Velocity, adiabatic compressibility, intermolecular free length and specific acoustic impedance have been evaluated. From the experimental data, it has been found that L1 ascribed higher ultrasonic velocity as compared to other molecular probes L2 and L3. The strength and nature of interaction between the molecular probes and DMSO solvents has been discussed. Scanning electron microscope studies of molecular probes are performed to discuss the microstructure and surface functionalities

Magnetoelectric ordering of BiFeO3 from the perspective of crystal chemistry

In this paper we examine the role of crystal chemistry factors in creating conditions for formation of magnetoelectric ordering in BiFeO3. It is generally accepted that the main reason of the ferroelectric distortion in BiFeO3 is concerned with a stereochemical activity of the Bi lone pair. However, the lone pair is stereochemically active in the paraelectric orthorhombic beta-phase as well. We demonstrate that a crucial role in emerging of phase transitions of the metal-insulator, paraelectric-ferroelectric and magnetic disorder-order types belongs to the change of the degree of the lone pair stereochemical activity - its consecutive increase with the temperature decrease. Using the structural data, we calculated the sign and strength of magnetic couplings in BiFeO3 in the range from 945 C down to 25 C and found the couplings, which undergo the antiferromagnetic-ferromagnetic transition with the temperature decrease and give rise to the antiferromagnetic ordering and its delay in regard to temperature, as compared to the ferroelectric ordering. We discuss the reasons of emerging of the spatially modulated spin structure and its suppression by doping with La3+.Comment: 18 pages, 5 figures, 3 table