Search

Greenhouses play a significant function in the modern agriculture economy even if require great amount of energy for heating systems. An interesting solution to alleviate the energy costs and environmental problems may be represented by the use of geothermal energy. The aim of this paper, based on measured experimental data, such as the inside greenhouse temperature and the heat pump performance (input and output temperatures of the working fluid, electric consumption), was the evaluation of the suitability of low enthalpy geothermal heat sources for agricultural needs such as greenhouses heating. The study was carried out at the experimental farm of the University of Bari, where a greenhouse was arranged with a heating system connected to a ground-source heat pump (GSHP), which had to cover the thermal energy request. The experimental results of this survey highlight the capability of the geothermal heat source to ensue thermal conditions suitable for cultivation in greenhouses even if the compressor inside the heat pump have operated continuously in a fluctuating state without ever reaching the steady condition. Probably, to increase the performance of the heat pump and then its coefficient of performance within GSHP systems for heating greenhouses, it is important to analyse and maximise the power conductivity of the greenhouse heating system, before to design an expensive borehole ground exchanger. Nevertheless, according to the experimental data obtained, the GSHP systems are effective, efficient and environmental friendly and may be useful to supply the heating energy demand of greenhouses.

A pilot power system formed by photovoltaic panels, alkaline electrolyser and fuel cell stacks was designed and set up to supply the heating system of an experimental greenhouse. The aim of this paper is to analyse the main safety aspects of this power system connected to the management of the pressured hydrogen, such as the explosion limits of the mixture hydrogen-oxygen, the extension of the danger zone, the protection pressure vessels and the system to make unreactive the plant. The electrolyser unit is the core of this plant and from the safety point of view has been equipped with devices able to highlight the malfunctions before they cause damages. Alarm situations are highlighted and the production process is cut off in safe conditions in the event that the operational parameters have an abnormal deviation from the design values. Also the entire power system has been designed so that any failure to its components does not compromise the workers’ safety even if the risk analysis is in progress because technical operations are being carried out for enhancing the plant functionality, making it more suitable to the designed task of supplying electrically the greenhouse heating system during cold periods. Some experimental data pertinent to the solar radiation and the corresponding hydrogen production rate are also reported. At present it does not exist a well-established safety reference protocol to design the reliability of these types of power plants and then the assumed safety measures even if related to the achieved pilot installation, can represent an original base of reference to set up guidelines for designing the safety of power plants in the future available for agricultural purposes.

Sugar beet is an extensive crop of great agronomic value with significant productive and economic returns and Ukraine’s sugar beet accounts for about 5.1% of the overall world production. Sugar beets and the by-products resulting from its manufacturing transformation are a significant renewable energy resource. A new high-quality performance prototype of a sugar beet top harvester, front mounted on a tractor, was built by the authors in Ukraine. The aim of this study is to evaluate the main performance parameters related to the operation of this new machine. Field tests were carried out linking the prototype to a wheel tractor, whilst suitable sensors measured the significant kinematic and dynamic parameters, allowing experimental data collection to assess the machine’s performance parameters. The entire technological process of harvesting and transporting the beet tops to the beet top storage unit required power ranging from 6.42 to 17.65 kW. At the topmost tested forward speed, the required tractor traction force was less than 1.9 kN with the power required by the shaft that drives the screw conveyor ranging from 3.1 to 4.6 kW. This value was the lowest for a speed of the tractor–beet top harvesting machine aggregate ranging from 0.9 to 1.2 m · s − 1 .

The mechanical behaviour of an agricultural tyre is a matter of extreme interest as it is related to the comfort of operators, to the adherence of agricultural machines, and to the compaction of agricultural soil. Moreover, the deformability of the tyres plays a fundamental role in vehicle stability in terms of side rollover. The behaviour of a loaded tyre during its deformation is complex, due to the combined contributions of the carcass components, the tread rubber and the air contained within it. Therefore, this study proposes an experimental–numerical approach for the mechanical characterization of agricultural tyres based on real-scale experiments and matches these results with a finite-element (FE) model. The tyre flattening in the elastic field has been described using two coefficients (Young’s modulus “E”, Poisson’s ratio “ν”), whose values have been identified with an iterative FEM procedure. The proposed approach was applied to two different tyres (420/85 R24 and 460/85 R34), each one inflated at two different pressures (1.0 bar and 1.6 bar). Young’s modulus was appreciated to be highly variable with the inflation pressure “p” of the tyres. Furthermore, the response surface methodology was applied to find two mathematical regression models, useful for studying the variations of the tyre footprint dimensions according to the type of tyre. This simple approach can be applied in other simulations without suffering any loss of accuracy in the description of the phenomenon.

Nowadays, heating using wood, briquettes, or pellets is a curious replacement to fossil fuels such as coal, oil, or gas. Unfortunately, the combustion of biofuels, especially in low-power boilers with unstable operating conditions, releases a lot of gas pollutants (e.g., carbon monoxide (CO), nitric oxide (NO), and various organic compounds) that are usually generated due to the incomplete product combustion. The combustion of biofuel in grate boilers with top-down ignition is a new approach, popular in society (mainly used for coal fuels), which improves the combustion process and reduces the amount of pollutants emitted. This study evaluated the impact of ignition techniques on the emission level of gas pollutants during the combustion of wood logs, briquettes, and pellets of pine in grate-based charging boilers. The combination of top ignition mode with pinewood logs allowed us to achieve a reduction of 6% in CO and sulfur dioxide (SO2) emission into the atmosphere. However, the combination of top-down ignition mode with pellets and briquettes produced, in fully operational conditions, 1- to 18-fold higher levels of CO and SO2 respectively, than bottom-up ignition, after an initial period of low level CO and SO2 emissions. During the tests (mainly with ignition from top), substantial emissions of NO were observed of up to 400 mg·m−3 at 10% O2. Therefore, further research is required to decrease emission related to the content of nitrogen in biomass. In this respect, research of impact on the combustion temperature of such emissions is needed.

This study firstly examined certain methods of vineyard management typically adopted in Apulia for both table grapes and wine grapes. In the later phenological stages, guyot or spurred cordon vineyards have extremely abundant vegetation, which drastically limits the space available between the rows for the passage of a tractor, even for a narrow-track vehicle. On the other hand, vegetation in tendone vineyards is situated at approximately 1.90 m above the soil surface, so that total tractor height must be compatible with this cultivation method. Foliage canopies in these types of vineyard cultivation system were evaluated at the times of their maximum growth in order to identify the maximum possible size of a prototype tractor that would be able to pass between vineyard rows without interfering in any way with the vegetation and fruits. Using the results of field measurements, it was established that the prototype tractor must have a maximum height of 1600 mm, with a minimum front axle track of less than 1100 mm and a back axle track of less than 1000 mm. A tractor built to these specifications is now being tested in order to compare its performance with that of other tractors commonly used in Apulia in various agricultural contexts.

The intrinsic factor of variability of renewable energy sources often limits their broader use. The photovoltaic solar systems can be provided with a power back up based on a combination of an electrolyser and a fuel cell stack. The integration of solar hydrogen power systems with greenhouse heating equipment can provide a possible option for powering stand-alone greenhouses. The aim of the research under development at the experimental farm of Department of Agro-Environmental Sciences of the University of Bari Aldo Moro is to investigate on the suitable solutions of a power system based on photovoltaic energy and on the use of hydrogen as energy vector, integrated with a ground source heat pump for greenhouse heating in a self sustained way. The excess energy produced by a purpose-built array of solar photovoltaic modules supplies an alkaline electrolyser; the produced hydrogen gas is stored in pressured storage tank. When the solar radiation level is insufficient to meet the heat pump power demand, the fuel cell starts converting the chemical energy stored by the hydrogen fuel into electricity. This paper reports on the description of the realised system. Furthermore the efficiency and the operational mode of the electrolyser were evaluated during a trial period characterised by mutable solar radiant energy. Anyway the electrolyser worked continuously in a transient state producing fluctuations of the hydrogen production and without ever reaching the steady-state conditions. The Faradic efficiency, evaluated by means of an empirical mathematic model, highlights that the suitable working range of the electrolyser was 1.5÷2.5 kW and then for hydrogen production more than 0.21 Nm3h–1.

A comparison of three different methods to evaluate the tree row volume (TRV) of a super-high-density olive orchard is presented in this article. The purpose was to validate the suitability of unmanned aerial vehicle (UAV) photogrammetry and 3D modeling techniques with respect to manual and traditional methods of TRV detection. The use of UAV photogrammetry can reduce the amount of estimated biomass and, therefore, reduce the volume of pesticides to be used in the field by means of more accurate prescription maps. The presented comparison of methodologies was performed on an adult super-high-density olive orchard, planted with a density of 1660 trees per hectare. The first method (TRV1) was based on close-range photogrammetry from UAVs, the second (TRV2) was based on manual in situ measurements, and the third (TRV3) was based on a formula from the literature. The comparisons of TRV2-TRV1 and TRV3-TRV1 showed an average value of the difference equal to +13% (max: +65%; min: −11%) and +24% (max: +58%; min: +5%), respectively. The results show that the TRV1 method has high accuracy in predicting TRV with minor working time expenditure, and the only limitation is that professionally skilled personnel is required.

The beet leaves and tops, which currently are excluded from the production process of sugar, could be an interesting opportunity for the production of renewable energy. Usually, the defoliators are joined with root collar remover machines, which are installed in front of the tractor. In working conditions on soils having natural roughness these front-mounted beet topper machines carried by tractors are affected by angular oscillations in a longitudinal-vertical plane that strongly affect the cutting uniformity. A theoretical study of these oscillations was carried out in this paper using Lagrange II kind equations, with the aim to assess the design and kinematic parameters of a front-mounted beet topper, corresponding to more stable and suitable movements in the longitudinal-vertical plane. A numerical simulation was then performed adopting the developed mathematical model. In order to improve the efficiency of this harvesting machine, a significant role is assumed by the soil preparation. In this work the stiffness and damping parameters of the feeler wheels pneumatic tires have been considered constant but further studies are in progress to assess their effective importance and influence for reducing the vibration of the front-mounted beet topper machine with the final aim to achieve a better machine design.

The evolution of climate and of electrical devices are raising users’ awareness about the protection of structures and plants against common overvoltage phenomena and those ones of atmospheric origin. Therefore, a continuous evolution of thunderstorm phenomena, increasingly concentrated and intense, is occurring. Conversely, electric devices are increasingly being equipped with electronics indispensable for their right functioning and are very sensitive to electromagnetic phenomena of an induced and conducted nature. In Italy, the law concerning work health and safety compels employers to assess the risk raised by lightning and to ensure that buildings, systems, structures, and equipment are protected from the effects of lightning in agreement with national and international technical standards. In the agricultural livestock sector, the new guidelines of agricultural policy in Italy requires farms to re-examine their structures, in particular the compatibility with animal protection requirements. In the event of a fault, the electric circuit must be interrupted in times not higher than expected and, in particular in the agricultural and zootechnical structures, it is necessary to maintain the contact voltages to negligible values by carrying out additional equipotential connections among the masses and with foreign masses that can be touched. Furthermore, particular attention is required in limiting the step voltage to which animals are particularly sensitive to, by connecting the electro-welded metal grids, which are commonly located under the concrete floor of animal shelters, to the earth collector. Taking in mind the aforesaid, the aim of this work was to analyze the technical standard concerning the protection from lightning with reference to the agricultural livestock sector and the study of the salient components to set up a suitable lightning protection system for a medium-sized stable.

The employment of bales is of considerable interest in the agricultural sector due to the mechanization of the production chain, the ease of their manipulation and transport, the low requirements for, and flexibility of, their storage and the low manpower requirements. Forage bales are mainly employed in zootechny, which albeit with important changes, is today still an essential economic sector for our society. The optimization of results in the zootechnical field depends largely on the feeding of the animals; in this regard, fodder-crops play a fundamental role in the European agricultural and economic sector. The soil inside the fodder is often the vehicle for a large number of CFUs (colony forming units) of bacteria of the Clostridium genus, with consequent repercussions for the welfare of the cows as well as for the quality of the milk products. The purpose of this work was to assess the performance of the large square baler HD 1270, made by the Italian manufacturer “Cicoria Square Bales”, whose main characteristic is the high cleanliness level of the dried fodder. The experimental tests carried out seem to confirm the efficacy of the technical solutions adopted for this machine. However, in order to better understand the reliability of the machine in lowering the amount of impurities and soil present in the built square bales, further tests in different working conditions should be carried out in order to statistically evaluate the influence and the mutual interaction of the operating parameters.

A research is under development at the Department of Agro- Environmental Sciences of the University of Bari “Aldo Moro” in order to investigate the suitable solutions of a power system based on solar energy (photovoltaic) and hydrogen, integrated with a geothermal heat pump for powering a self sustained heated greenhouse. The electrical energy for heat pump operation is provided by a purpose-built array of solar photovoltaic modules, which supplies also a water electrolyser system controlled by embedded pc; the generated dry hydrogen gas is conserved in suitable pressured storage tank. The hydrogen is used to produce electricity in a fuel cell in order to meet the above mentioned heat pump power demand when the photovoltaic system is inactive during winter night-time or the solar radiation level is insufficient to meet the electrical demand. The present work reports some theoretical and observed data about the electrolyzer operation. Indeed the electrolyzer has required particular attention because during the experimental tests it did not show a stable operation and it was registered a performance not properly consistent with the predicted performance by means of the theoretical study.

The use of entomopathogenic nematodes (EPNs) as a non-chemical treatment system is one of the most modern techniques promoted by the 2008/128/EC standards for the biological control of plant pathogens. The distribution of EPNs could be carried out with the same sprayers used for the distribution of pesticides. This research is focused on the effects of the mechanical stress due to hydraulic compression on EPNs Italian strains, Steinernema feltiae and Heterorhabditis bacteriophora, to assess their residual strength and vitality under laboratory tests. Liquid suspensions of nematodes were subjected to 8 different levels of hydrostatic pressure from 5 to 40 bar. The hydraulic compression test was conducted through a hydrostatic compression system specifically designed for the experimental test. Although correlation curves show an increment of 14% in nematode mortality, the statistical analysis did not show any significant effect of static pressure on the vitality and infectivity of EPNs, that makes them suitable for field application with sprayers. These preliminary positive results on the effects of compression on the viability of EPNs are preparatory to subsequent field tests under high pressure. [ABSTRACT FROM AUTHOR]

Stelidota geminata (Say) (Coleoptera: Nitidulidae), also known as strawberry sap beetle is considered to be serious pest of strawberry worldwide. All stages of this pest feed on ripe fruitswhich makes its control with chemical insecticides extremely difficult. This work was testing susceptibility of last instar larvae of S. geminata to three, among commercially the most commonly used species of entomopathogenic nematodes Heterorhabditis bacteriophora, Steinernema carpocapsae and Steinernema feltiae (Rhabditida: Heterorhabditidae and Steinernematidae), including two native strains. The present work was carried out through two types of the experiments. First experiment was in plastic Petri dishes with the nematodes applied on filter paper. Second one, in attempt to approach to more natural conditions, effect of the entomopathogenic nematodes on insect's mortality was tested in containers filled with sand. Mortality of S. geminata larvae in Petri dishes in highest nematode concentrations of about 100 infective juveniles per cm2 was 90%, 82% and 70% for commercial strains of S. carpocapsae, H. bacteriophora and S. feltiae and 76% and 64% for H. bacteriophora and S. feltiae native populations. In containers with sand mortality was higher than in Petri dishes and the highest recorded insect mortality with about 50 nematodes per cm² was 99.5%, 89%, 75.5%, 69% and 66% with commercial strains S. feltiae, S. carpocapsae and H. bacteriophora, and native strains H. bacteriophora and S. feltiae, respectively. [ABSTRACT FROM AUTHOR]

A greenhouse containing an integrated system of photovoltaic panels, a water electrolyzer, fuel cells and a geothermal heat pump was set up to investigate suitable solutions for a power system based on solar energy and hydrogen, feeding a self-sufficient, geothermal-heated greenhouse. The electricity produced by the photovoltaic source supplies the electrolyzer; the manufactured hydrogen gas is held in a pressure tank. In these systems, the electrolyzer is a crucial component; the technical challenge is to make it work regularly despite the irregularity of the solar source. The focus of this paper is to study the performance and the real energy efficiency of the electrolyzer, analyzing its operational data collected under different operating conditions affected by the changeable solar radiant energy characterizing the site where the experimental plant was located. The analysis of the measured values allowed evaluation of its suitability for the agricultural requirements such as greenhouse heating. On the strength of the obtained result, a new layout of the battery bank has been designed and exemplified to improve the performance of the electrolyzer. The evaluations resulting from this case study may have a genuine value, therefore assisting in further studies to better understand these devices and their associated technologies. [ABSTRACT FROM AUTHOR]