Andrea Acampora

Effective water resource management in agriculture is a pivotal challenge for environmental sustainability and the economic viability of crop production. The present study, conducted at the CREA research station (Monterotondo, Italy), analyzed a precision irrigation strategy based on an automated drip irrigation system with soil moisture sensors, applied to a 15-year-old high-density poplar plantation for energy production. Five treatments were compared: a non-irrigated control (T0) and four irrigation levels based on soil moisture thresholds (T1 ≤ 20%, T2 ≤ 30%, T3 ≤ 40%, T4 ≤ 50%). The aim of this study was to assess the economic feasibility of irrigated poplar plantations, considering expected increases in biomass production and related environmental impacts. The economic evaluation used the Life Cycle Costing (LCC) method, while the environmental assessment applied Life Cycle Assessment (LCA) with the AWARE indicator to quantify the water scarcity footprint. Finally, an integrated assessment using the TOPSIS multi-criteria method was performed to identify the most sustainable treatment. Over the 15-year period, T0 (no irrigation) was the preferred option (Preferred Index Pi = 1.000), followed by T3 (Pi = 0.637) and T4 (Pi = 0.586), considering equal weighting of economic and environmental impacts. Conversely, the low irrigation treatment (T1) was the least sustainable (Pi = 0.379), followed by T2 (Pi = 0.486). While irrigation appears unviable if environmental impacts are prioritized, higher biomass value can improve the economic sustainability of treatments with greater water use (T3 and T4) when economic factors dominate.

Coffee is one of the most widely consumed beverages in the world; the European Union alone consumes about 2.5 million tons of coffee per year. Yearly, millions of tons of coffee residues are generated, becoming an attractive material for circular economy flows. This study explores the potential of utilizing pelletized coffee residues as sustainable bioenergy sources within the framework of a circular economy. The coffee residues, obtained from damaged capsules and pods from factories, were utilized in pure form or blended with sawdust at different percentages, then analyzed with respect to their physical and thermochemical parameters. The results indicate that unblended coffee residues exhibit favorable combustion properties with respect to heating value (18.84 MJ kg⁻¹), but also high concentrations of N (4.14%) compared to the conventional pellets obtained from other agricultural residues. The blending with woody material negatively affects both durability and bulk density, but simultaneously promotes a reduction in ash content (3.09%) and N content (1.94%). In general, this study confirmed the findings of previous scientific reports, highlighting that at least 50% blending with low-nitrogen biomasses is necessary to reach the marketability of the product. In addition, this study highlighted the criticality in terms of durability that these mixtures confer to the final product, emphasizing that future research should focus on optimizing the combination of these factors to improve the properties of the pellet.

Biomass, due to its neutrality in terms of greenhouse gas emissions into the atmosphere during its life cycle, is considered an interesting renewable source for energy production as an alternative to the use of more polluting fossil fuels. Among the different wood fuels, pellets are convenient for use in dedicated stoves, and pellet heating systems have a high energy efficiency. The aim of this work was to estimate the economic and global warming potential (GWP100a) generated along the thermal energy supply chain of wood pellets, starting from the production of raw biomass from dedicated poplar cultivations and ending with the use of pellets in stoves by the end-user to produce thermal energy and ash. The Eco-Efficiency Indicator (EEI) was used to link the economic and environmental performance for eight proposed scenarios, obtained by combining different levels of mechanisation for poplar harvesting and wood biomass management before arrival at the pellet plant. For the thermal energy produced by the poplar wood pellet, the GWP100a ranged from 1.5 × 10⁻² to 2.1 × 10⁻² kg CO₂−eq MJ⁻¹ for three-year-old plantations and from 1.9 × 10⁻² to 2.4 × 10⁻² kg CO₂−eq MJ⁻¹, for six-year-old plantations. In terms of eco-efficiency of the baseline scenario (EEIb), the most favourable scenarios remain those linked to the use of biomass from three-year-old poplar plantations, with EEIb values ranging from 0.31 to 0.60 € kgCO₂−eq⁻¹, compared to from 0.29 to 0.36 € kgCO₂−eq⁻¹ for pellets obtained from biomass produced from six-year-old poplar plantations. In terms of the Global Eco-Efficiency Indicator (EEIg), which also takes into account the positive effect on the reduction of greenhouse gases due to the storage of carbon in the soil by the plantations and the reduction of emissions from avoided fossil fuels, the most favourable scenarios remain those linked to the use of biomass from three-year-old poplar plantations, with EEIg values that vary in the range of 0.60 ÷ 1.04 € kgCO₂−eq⁻¹, compared to 0.55 ÷ 0.62 € kg CO₂−eq⁻¹ for thermal energy obtained using biomass from six-year-old poplar plantations.

With the aim of extending the production of renewable energy from lignocellulosic materials by improving their energy characteristics, the authors have started a series of experimental activities that involve a densification process of the wood material and a subsequent quantitative and qualitative characterization of the different pellets produced. The research activity was focused on different types of pellets obtained using biomass deriving from dedicated energy crops (medium rotation forestry), pruning residues of agricultural crops, thinning interventions in planted forests, and, lastly, residues from the maintenance of urban greenery. Among the 15 parameters that were investigated, 9 (length, diameter, fusibility, As, Cr, Cu, Pb, Ni, and Zn) were within the limits set by current legislation for all the analyzed pellets. The same was not detected for the remaining 6 parameters (bulk density, heating value, ash, N, durability, and cadmium), the value of which did not reach the quality requirements established by the standards. The biomass obtained from medium rotation forestry plants (MRF) and forest residues turned out to be the best source of material to be used to produce pellets. Within these two groups, the best results were found for eucalypt, except for the heating value. Pellets from MRF also showed interesting values of durability and nitrogen content (classes A1 vs. A2).

The increase in high-density hazelnut (Corylus avellana) areas drives the interest in practices of precision management. This work addressed soil apparent electrical conductivity (ECa), RGB aerial (UAV) images, proximal sensing, and field scouting in delineating and validating management zones (MZs) in a 2.96 ha hazelnut grove in Italy. ECa data were fitted to a semi-variogram, interpolated (simple kriging), and clustered, resulting in two MZs that were subjected to soil analysis. RGB imagery was used to extract tree canopies from the soil background and determine two vegetation indices (VIs) of general crop status: the Visible Atmospherically Resistant Index (VARI) and the Normalized Green-Red Difference Index (NGRDI). Then, plant growth parameters were manually assessed (tree height, crown size, etc.) and a proximal VI, the Canopy Index (CI), was determined with the MECS-VINE^® vertical multisensor. MZ1 was characterized by lower ECa values than MZ2. This was associated with a lower clay content (9% vs. 21% in MZ1 vs. MZ2) and organic matter content (1.03% vs. 1.51% in MZ1 vs. MZ2), indicating lower soil fertility in MZ1 vs. MZ2. Additionally, hazelnut trees had significantly smaller canopies (1.42 vs. 1.94 m² tree⁻¹) and slightly lower values of VARI, NGRDI, and CI in MZ1 vs. MZ2. In conclusion, our approach used ECa to identify homogeneous field areas, which showed differences in soil properties influencing tree growth. This is the premise for differential hazelnut management in view of better efficiency and sustainability in the use of crop inputs.

Water resources are increasingly limited and less available, so improving water use efficiency is particularly pressing in the agricultural sector, where inefficient irrigation systems are often in operation. Drip irrigation is one of the most water-saving systems that can optimize distribution according to the actual needs of the crop. In the present study, an engineered drip irrigation system was applied to a poplar crop dedicated to the production of biomass for energy use. The aim was to evaluate the influence of the supply of different volumes of irrigation water on crop growth. Four levels of water supply were tested (theses T1, T2, T3, and T4), each determined by different intervention thresholds established by using four soil moisture sensors, one for each thesis (PLOT) (20, 30, 40, and 50 percent, respectively). In the third growing season, the effect of the different amounts of irrigation water supplied on plant growth was particularly evident between control T1 (104 m³ ha⁻¹) compared with T2 (540 m³ ha⁻¹), T3 (1924 m³ ha⁻¹) and T4 (4549 m³ ha⁻¹). Regarding biomass production, no statistical differences were found between T2 (8.97 Mg DM ha⁻¹ year⁻¹), T3 (9.99 Mg DM ha⁻¹ year⁻¹) and T4 (10.02 Mg DM ha⁻¹ year⁻¹), but they were all different from T1 (7.09 Mg DM ha⁻¹ year⁻¹. This leads to the conclusion, at least up to the third growing season, that with equal satisfactory levels of biomass production, water and energy savings can be achieved by choosing intermediate levels of water supply (e.g., with the sensor at 30%) as compared to the maximum value tested.

The forest biomass, as a renewable energy source, can significantly contribute to the progressive replacement of fossil fuels in energy production, with a positive final balance in terms of greenhouse gas emissions. One of the different sources of woody biomass supply is represented by short rotation coppices (SRC) plantations, currently present in various European countries for a total of about fifty thousand hectares. In Italy, part of the SRC surface has been converted into other more profitable crops, both the low levels reached by the woodchips market price and the scarce availability of specific public incentives. In this study, the authors expose the results of the models for evaluating work time, productivity, and costs of the felling operation on SRC poplar plantations with 8- and 11-year-old trees. The aim is to evaluate the economic sustainability in the use of advanced mechanization on these plantations. The machine was a crawler excavator equipped with a shear head. In the 11-year-old plantation, the productivity estimation model returned a range of 1.09–18.93 Mg h⁻¹ (average 5.56 ± 3.88 SD) when the weight variation of the trees was 20–491 kgw (average 100.41 ± 87.48 SD). In the 8-year-old poplar, the range was 1.02–11.60 Mg h⁻¹ (average 3.80 ± 1.71 SD), for weight variation of 17–137 kgw (average 50.57 ± 18.82 SD). The consequent variation in unit cost was EUR 2.82–51.63 Mg⁻¹ and EUR 4.05–49.65 Mg⁻¹, corresponding to EUR 1252.17–3463.78 ha⁻¹ and EUR 922.49–2545.11 ha⁻¹ for 11- and 8-year-old trees, respectively.

Biomass occupies a very important place among renewable energy sources, and the residual biomass recovery chain represents a sector of fundamental importance. Our work focused on the production of pellets by pruning residues from two of the most important woody crops in Italy: hazelnut and olive groves. We found a higher value of bulk density for the hazelnut pellet (581.30 kg m⁻³ vs. 562.38 kg m⁻³) and a higher value of length for the olive pellet (16.66 mm vs. 10.47 mm). The percentages of durability were very similar (98%). The low heating value and ash content of hazelnut and olive were 17.21 MJ kg⁻¹ and 3.1%, and 16.83 MJ kg⁻¹ and 2.5%. A higher concentration of Cu, Pb, and Ni was observed in the hazelnut. The contrary was observed for the concentration of Zn. N content was 0.77% and 1.24% for the hazelnut and the olive, respectively. The concentration of S was 0.00% for both. The quality parameters that do not meet current standards could be improved by mixing these materials with different types of wood.

As demonstrated for some time, the reduction of greenhouse gases in the atmosphere can also take place using agroforestry biomass. Short-rotation coppice (SRC) is one of the sources of woody biomass production. In our work, the supply of woody biomass was considered by examining four different cutting shifts (2, 3, 4 and 5 years) and, for each, the Global Warming Potential (GWP) was evaluated according to the IPCC 2007 method. Regarding the rotation cycle, four biomass collection systems characterized by different levels of mechanization were analyzed and compared. In this study, it was assumed that the biomass produced by the SRC plantations was burned in a 350 kWt biomass power plant to heat a public building. The environmental impact generated by the production of 1 GJ of thermal energy was assessed for each of the forest plants examined, considering the entire life cycle, from the field phase to the energy production. The results were compared with those obtained to produce the same amount of thermal energy from a diesel boiler. Comparing the two systems analyzed, it was shown that the production and use of wood biomass to obtain thermal energy can lead to a reduction in the Global Warming Potential of over 70% compared to the use of fossil fuel.

The delivery of biomass products from the production place to the point of final transformation is of fundamental importance within the constitution of energy chains based on biomass use as a renewable energy source. Transport can be one of the most economically expensive operations of the entire biomass energy production process, which limits choices in this sector, often inhibiting any expansive trends. A geographic identification, through remote sensing and photo-interpretation, of the different biomass sources was used to estimate the potential available biomass for energy in a small-scale supply chain. This study reports on the sustainability of transport costs calculated for different types of biomass sources available close a biomass power plant of a small-scale energy supply chain, located in central Italy. To calculate the transport cost referred to the identified areas we used the maximum travel time parameter. The proposed analysis allows us to highlight and visualize on the map the areas of the territory characterized by greater economic sustainability in terms of lower transport costs of residual agroforestry biomass from the collection point to the final point identified with the biomass power plant. The higher transport cost was around €40 Mg⁻¹, compared to the lowest of €12 Mg⁻¹.