Global Navigation Satellite Systems (GNSS) allow the determination of the 3D position of a point on the Earth’s surface by measuring the distance from the receiver antenna to the orbital position of at least four satellites. Selecting and buying a GNSS receiver, depending on farm needs, is the first step for implementing precision agriculture. The aim of this work is to compare the positioning accuracy of four GNSS receivers, different for technical features and working modes: L1/L2 frequency survey-grade Real-Time Kinematic (RTK)-capable Stonex S7-G (S7); L1 frequency RTK-capable Stonex S5 (S5); L1 frequency Thales MobileMapper Pro (TMMP); low-cost L1 frequency Quanum GPS Logger V2 (QLV2). In order to evaluate the positioning accuracy of these receivers, i.e., the distance of the determined points from a reference trajectory, different tests, distinguished by the use or not of Real-Time Kinematic (RTK) differential correction data and/or an external antenna, were carried out. The results show that all satellite receivers tested carried out with the external antenna had an improvement in positioning accuracy. The Thales MobileMapper Pro satellite receiver showed the worst positioning accuracy. The low-cost Quanum GPS Logger V2 receiver surprisingly showed an average positioning error of only 0.550 m. The positioning accuracy of the above-mentioned receiver was slightly worse than that obtained using Stonex S7-G without the external antenna and differential correction (maximum positioning error 0.749 m). However, this accuracy was even better than that recorded using Stonex S5 without differential correction, both with and without the external antenna (average positioning error of 0.962 m and 1.368 m).

Peat is a common substrate used for the cultivation of potted plants. However, the use of peat in horticulture has recently been questioned from an environmental standpoint, since it is a non-renewable resource and plays a major role in atmospheric CO₂ sequestration. The aim of this work was to assess the potentialities of substrates obtained from vermicompost, compost and anaerobic digestion processes to partially substitute peat for sage (Salvia officinalis L.) cultivation. Therefore, we planned an experiment to assess the effect of these substrates on essential oil (EO) yield and composition, as well as on leaf nutrients concentration of sage plants. The three substrates were mixed with commercial peat (Radicom) at a ratio of 40% of alternative substrates and 40% of commercial peat. The chemical properties of the alternative substrates did not affect the leaf content of macro and micronutrients, as well as of heavy metals. Moreover, the EO yield and quality was not affected by the substrates and did not differ among them. Results provided evidence that the three alternative substrates can be used to partially substitute peat in soilless cultivation of sage plants. However, due to the higher values of the electrical conductivity of the substrates obtained from composting and anaerobic digestion processes, such substrates must be used with caution.

Precision agriculture is a management strategy to improve resource efficiency, production, quality, profitability and sustainability of the crops. In recent years, olive tree management is increasingly focused on determining the correct health status of the plants in order to distribute the main resource using different technologies. In the olive grove, the focus is often on the use of multispectral information from UAVs (Unmanned Aerial Vehicle), but it is not known how important spectral and biometric information actually is for the agronomic management of the olive grove. The aim of this study was to investigate the ability of multispectral data acquired from a UAV platform to predict nutritional status, biometric characteristics, vegetative condition and production of olive orchard as tool to DSS. Data were collected on vegetative characteristics closely related to vigour such as trunk cross-sectional area (TCSA), Nitrogen concentration of the leaves, canopy area and canopy volume. The production was collected for each plant to create an accurate yield map. The flight was carried out with a UAV equipped with a multispectral camera, at an altitude of 50 m and with RTK correction. The flight made it possible to determine the biometric condition and the spectral features through the normalized difference vegetation index (NDVI). The NDVI map allowed to determine the canopy area. The Structure for Motion (SfM) algorithm allow to determine the 3D canopy volume. The experiment showed that the NDVI was able to determine with high accuracy the vegetative characteristic as canopy area (r = 0.87 ***), TCSA (r = 0.58 ***) and production (r = 0.63 ***). The vegetative parameters are closely correlated with the production, especially the canopy area (r = 0.75 ***). Data clustering showed that the production of individual plants is closely dependent on leaf nitrogen concentration and vigour status.

The aim of this work is to assess the usefulness of biowaste deriving from Circular Bioeconomy (CBE) processes (i.e., vermicompost, compost and digestate), as growing substrates for the partial or total replacement of peat, by measuring the vegetation biometric parameters of sage (Salvia officinalis L.)—leaf area; Soil Plant Analysis Development (SPAD) value (index of chlorophyll concentration); fresh and dry weight of leaves; stem weight; root length. The results showed that vermicompost positively influenced most of above parameters (+16.7% for leaf area, +7.3% for fresh leaf weight, +6.4% for dry leaf weight, +8.5% for fresh stem weight, +0.9% for dry stem weight, +16% for root length) and, therefore, can be used as a sustainable growing substrate, alternative to peat, for the sage soilless cultivation. Yet, the results of some biometric parameters are better with peat rather than with compost (−7.2% for SPAD value, −47.3% for fresh leaf weight, −46.8% for dry leaf weight, −32.9% for fresh stem weight, −39.1% for dry stem weight, −52.4% for fresh root weight, −56.6% for dry root weight) and digestate (−30.2% for fresh leaf weight, −33.6% for dry leaf weight, −23.9% for fresh stem weight, −27% for dry stem weight, −51.8% for fresh root weight, −34.4% for dry root weight, −16% for root length). Therefore, these results are interesting for potted plants in nursery activity, while the above differences must be verified also after the transplanting of the tested plants in open field. However, the use of all the above growing substrates alternative to peat allows the sustainable valorization of food industry by-products, plant biomass, animal manure and the Organic Fraction of Municipal Solid Waste (OFMSW).