Inadequate production practices are widely used in aquaculture management, causing excessive water and energy usage, as well as ecological damage. New approaches to sustainable aquaculture attempt to increase production efficiency, while reducing the quantities generated of wastewater and sludge. The sustainable operating techniques are often ineffective, expensive, and difficult to implement. The present article proposes a zero-waste production system, designed for growing fish and vegetables, using a new circular operational concept that creates synergies between fish farming and horticulture. In order to optimize the operational flows with resources, products, and wastes in an integrated zero-waste food production cluster, a business model was designed associating three ecological production practices: a closed fishing pond, a technology for growing vegetables in straw bales, and a composting system. The design had the role to assist the transition toward multiple circular material flows, where the waste can be fully reintegrated into the production processes. A comparative evaluation was conducted in three alternative growing environments, namely, a soilless culture established in straw bales, a culture grown in soil that had received compost fertilizer, and the conventional farming technique. When compared to conventional methods, experiments showed a significant increase in the cluster’s cumulative productivity, resulting in a 12% improvement in energy efficiency, 18% increase in food production, and 25% decrease in operating expenses.

Starting from the influencing parameters of threshing and separation and implicit seed losses that occur within this process, this paper searched for and identified the optimal threshing regimes to minimize losses depending on the process parameters. The evacuation losses (p_ev) depend on threshing rotor speed (n) and implicit rotor peripheral speed (v_p), material feed speed (v_a), the space between the rotor and counter-rotor (δ), material feed flow (Q), material density (ρ), and the length of the threshing apparatus (L). As the parameters ρ and L are constant, the variation of losses in relation to each of the arguments was followed: v_p, Q, ρ, and v_a, respectively, for the minimization of losses by the variation of the loss function by two arguments each (represented graphically); the four arguments targeted being: v_p, v_a, ρ, and Q. Using these input parameters, it was possible to determine the optimal threshing regimes for the variation of losses in relation to the rotor peripheral speed, the feed flow, the space between the rotor and the counter-rotor, and the feed speed, so as to obtain a seed separation percentage (S_s) as close as possible to 100% (and implicitly the smallest threshing losses—towards zero) in relation to these parameters.

This paper presents theoretical and experimental research studying the influence of process parameters on the quality of biomass pellets. A validated mathematical model was developed, expressing the density of biomass pellets as determined by moisture content, compression pressure, process heat, the initial density of the material, pelleting speed and initial volume of the material. The experiments for determining the influence of these parameters on the compression of biomass into pellets and optimizing the process were conducted on a heated single pellet compression device, using fir sawdust as raw material. To describe and study the process, four input and control parameters were varied—raw material moisture, pelleting speed, maximum force applied and pelleting die temperature. From the experiments, it was noticed that overall, moisture and pressure have the most important effect on the compression process and pelleting speed, and heat applied also affected the process. Pellet density decreased when pelleting speed and material moisture increase and the density increased with a higher compression pressure and higher heat during the process.

In agrotechnical practice, it was found that between qualitative indices, which express the sowing precision achieved by precision planters determined in the laboratory, and those determined under operating conditions, that there are certain differences, which are sometimes quite significant. The decrease in the value of the quality indices was manifested by the increase of the number of mistakes, either of the number of double planting holes (with at least two seeds), or of the number of missing planting holes. Both cases are unfavorable for the agricultural producer, generating production losses. This paper discusses the influence of the degree of soil grinding on sowing precision in operating conditions, by determining the spectrum of the vibrations induced in the mechanical structure of row units of a precision planter in contact with the soil of three different plots for three working speeds: 4, 6, and 8 km·h⁻¹. Later, the vibrations were simulated under laboratory conditions, on the stand, by means of rubber hemispheres (with diameters between 30 and 100 mm, corresponding to soil fractions resulting from the determination of the degree of soil grinding) mounted on rubber bands, which actuated the seed meters, for testing under an accelerated regime, outside of the optimal agricultural periods (out of season: beginning mid-May until the end of March), in order to obtain the accuracy of the precision planters. It was found that the sowing precision determined in stationary conditions on the stand, and on a plot with an appropriate degree of seedbed preparation, decreased between 2.92% (at 4 km·h⁻¹) and 6.67% (at 8 km·h⁻¹). The main objective of the tests was to reduce labor costs, which was necessary for the staff involved for determining the qualitative indices of work in real field operating conditions, eliminating fuel consumption, while reducing the duration of testing dependent on meteorological factors (season, temperatures, and precipitation, etc.).

In the context of agricultural soil degradation caused by the extensive use of chemical amendments, ecological alternatives with minimal detrimental impact on ecosystems are gaining popularity. Recent advancements in processing technologies have improved the quality and extraction efficiency of bioactive compounds, particularly when multiple conventional or innovative techniques are being used to potentially overcome the most common limitations. This paper proposes the development and testing of a hybrid technology design that employs two extraction techniques, namely ultrasound and high pressure, that can be used either separately or in tandem. An initial assessment of the prototype potential for isolating the desired compounds was made, by testing three various working regimens for the processing of a mixture of onion, pea, and soybean. By incorporating the bioactive compounds produced during the experimental phase in the seedling transplantation holes, we were able to test the potential of stimulating the development rate of vegetables and reducing the attack of pests. The extracts obtained using the hybrid technology showed positive results when used to reduce pest attacks (decreasing average attack frequency by 7%), however had negative effects when used to promote biostimulation, when acted as an inhibitor. The hybrid extraction approach improved the mass transfer into solvent by 14% when compared to high-pressure processing and by 7% when compared to sonication.

The bioaccumulation of trace metals in edible crops is a key pathway of dietary exposure, with direct implications for environmental health and food safety. This study specifically investigated the bioaccumulation and soil–plant transfer of lithium (Li) in edible crops, alongside other selected trace metals (Cu, Mn, Sr, Zn), to understand its unique environmental mobility and dietary exposure risks in onion, garlic, green salad, cucumber, and zucchini cultivated across Romania. Forty-two paired samples of vegetable tissues and rhizosphere soils were collected from eleven agricultural regions, and were analyzed using spectroscopic techniques. Soils were predominantly neutral to slightly acidic, conditions that significantly affected metal mobility and uptake. Results revealed element-specific decoupling between soil and plant concentrations. Essential micronutrients (Zn, Cu) showed higher transfer factors, consistent with active physiological uptake, while toxic non-essential metals (Pb, Cd) remained below European regulatory thresholds, reflecting effective exclusion mechanisms. Lithium exhibited spatially heterogeneous transfer patterns, strongly influenced by local geochemical variability. Curvilinear soil–plant relationships for Fe, Zn, Sr, Mn, Cu, and Li further underscored the role of soil chemistry in shaping translocation. These findings establish a robust baseline for assessing dietary risks, confirming the current low-risk status of vegetables in the surveyed regions, and provide valuable guidance for sustainable agricultural management and food safety monitoring.