Data envelopment analysis (DEA) has been recognized as a suitable tool for efficiency assessment of the economic and environmental performance of multiple similar units in the agri-food sector. In the present study, DEA methodologies were applied to 55 winter wheat farms in three farm sizes in Poland to benchmark the level of operational efficiency for each producer. Next, the potential reduction in the consumption levels of inputs were defined, and the environmental profits linked to these reduction targets were calculating. Our results indicate that 55% of the analysed farms operated efficiently. The technical efficiency scores of inefficient farms were 0.72 for small farms and 0.84 for medium and large ones. The production of 1 kg winter wheat results with average greenhouse gas (GHG) emissions of 0.448, 0.481, and 0.411 kg CO₂ eq. per kg of grain, for small, medium, and large farms, respectively. The performed analysis shows that GHG emissions per hectare depend on farm size and ranged from 2,378 kg CO₂ eq. for the small farms to 2,759 kg CO₂ eq. for large farms. The reduction of material input in inefficient farms, converted into environmental gains, resulted in GHG emissions reduction of 25.7, 29.0, and 28.6% for small, medium, and large farms, respectively. The estimated potential reduction of global warming potential (GWP) according to the DEA for the whole sample ranged from 7 to 18%, and was dependent on farm size. The major contributor to GWP was nitrous oxide field emissions (49-52%), followed by nitrogen fertilizer (31-33%), and diesel (11-13%). Raising operational efficiency is recommended for potential environmental improvement in the surveyed region.

Bioeconomy emerges under major current global challenges, both environmental and economic, that are related to the existence and use of bio-based resources; in this context, policy stakeholders and scientists seek and propose potential solutions. Bioeconomy is among the discussed strategies with the potential to offer solutions. In this framework, bioeconomy’s importance increased over the last several years, thus it is essential to identify and monitor its role and significance in an economy and assess its potentials and intersectoral relationships. In this framework, the current study, through a general equilibrium analysis, aims to identify the sectors that are related to the bioeconomy and assess their potential in the Polish economy as such quantitative studies do not exist in the literature for Poland. For doing so, an Input-Output model was built, identifying initially the bioeconomy sectors and, afterwards, estimating their linkage coefficients in order to capture their direct and indirect impacts on the Polish economy. Results indicate that the fully bio-based sectors, such as the agriculture and food sectors, have higher potentials to induce knock-on effects in the economy than the mixed bio-based sectors. Thus, the current study’s results can offer important information to policy makers for decision making, such as in the case of planning development in any mixed bio-based sectors, such as biofuels or biogas.

Two 16-year-old series of experiments with winter wheat grown in rotation after winter oilseed rape were used in the study. The experiments were located in the cold temperate dry and moist climate zones on light soils. Wheat was fertilized with nitrogen in the doses of 40, 80, 120, 160, and 200 kg N·ha⁻¹ per year. Through the several years of the experiment, critical N rates for maximum yield and gross margin from the linear-plus plateau regressions were 149 ± 23.9 and 112 ± 23.6 kg N·ha⁻¹, respectively. The estimated nitrogen indicators for these doses were as follows: nitrogen use efficiency (NUE) 93 and 108%, N surplus (Ns) 6.8 and −10.1 kg·N·ha⁻¹, yield-scaled Ns, N₂O, and NH₃ 3.5 and −0.2; 0.35 and 0.30; 0.31 and 0.25 kg N·Mg⁻¹, respectively. Experiments have shown that two strategies for reducing nitrogen losses on light soils under wheat cultivation are possible: by limiting the N dose to the critical values due to the yield requirements, or due to the gross margin. The analysis of the 11-year data for 2300 farm fields with winter wheat grown on light soils showed that only 10% of them were implementing the first strategy, and as much as 90% chose the second strategy.

The aim of this study was to compare four tools for calculation of nitrous oxide (N₂O) emissions under the renewable energy directive. All the tools follow the methodology of the international panel on climate change. The first calculations of N₂O fluxes were based on the Tier 1 method using the BioGrace tool. The second and the third ones followed the Tier 2 methodology, applying the global nitrous oxide calculator and the Lesschen emission factors, respectively. The last assessment was performed in accordance with the Tier 3 approach by using the denitrification- decomposition model. The N₂O fluxes were calculated for rapeseed cultivation in a 4-year crop rotation in Poland. The same input data were applied in all methods. The average of N₂O emissions varied in the range of 1.99-3.78 kg N₂O ha^-1 y^-1, depending on the approach used (Lesschen emission factors > denitrificationdecomposition > global nitrous oxide calculator > BioGrace). This paper illustrates that, at country level, the Lesschen emission factors method worked as well as the denitrification-decomposition model for Poland. The advantage of this approach is the simplicity of collecting the necessary data, in contrast to process-based modelling. Moreover, the Tier 2 method provides mitigation measures similar to the denitrification-decomposition model, related to crop type, climatic conditions, and management practices.

This paper uses the most appropriate measures and data sources to map the likely growth delinking of Polish economy for the period 1990-2016. Evidences of green growth exist and were assessed both qualitatively and quantitatively. This paper also examines the likely policy implications by means of cross-correlation analysis. The results indicate that Poland can be conceptualized as a successful paradigm prescribed by the ecological modernization theory since growth is not associated with human pressure on natural resources and does not produce detrimental environmental impacts.