This study deals with approaches for a social-ecological friendly European bioeconomy based on biomass from industrial crops cultivated on marginal agricultural land. The selected crops to be investigated are: Biomass sorghum, camelina, cardoon, castor, crambe, Ethiopian mustard, giant reed, hemp, lupin, miscanthus, pennycress, poplar, reed canary grass, safflower, Siberian elm, switchgrass, tall wheatgrass, wild sugarcane, and willow. The research question focused on the overall crop growth suitability under low-input management. The study assessed: (i) How the growth suitability of industrial crops can be defined under the given natural constraints of European marginal agricultural lands; and (ii) which agricultural practices are required for marginal agricultural land low-input systems (MALLIS). For the growth-suitability analysis, available thresholds and growth requirements of the selected industrial crops were defined. The marginal agricultural land was categorized according to the agro-ecological zone (AEZ) concept in combination with the marginality constraints, so-called ‘marginal agro-ecological zones’ (M-AEZ). It was found that both large marginal agricultural areas and numerous agricultural practices are available for industrial crop cultivation on European marginal agricultural lands. These results help to further describe the suitability of industrial crops for the development of social-ecologically friendly MALLIS in Europe.

Agricultural land abandonment due to biophysical and socioeconomic constraints is increasing across Europe. Meanwhile there is also an increase in bioenergy demand. This study assessed woody crop performance on several relevant types of marginal agricultural land in Europe, based on field experiments in Latvia, Spain and Ukraine. In Latvia, hybrid aspen was more productive than birch and alder species, and after eight years produced 4.8 Mg ha⁻¹ y⁻¹ on stony soil with sandy loam texture, when best clone and treatment combination was selected. In Spain, Siberian elm produced up to 7.1 Mg ha⁻¹ y⁻¹ on stony, sandy soil with low organic carbon content after three triennial rotations. In Ukraine, willow plantations produced a maximum of 10.8 Mg ha⁻¹ y⁻¹ on a soil with low soil organic carbon after second triennial rotation. The productivity was higher when management practices were optimized specifically to address the limiting factors of a site. Longer rotations and lower biomass yields compared to high-value land can be expected when woody crops are grown on similar marginal agricultural land shown in this study. Future studies should start here and investigate to what extent woody crops can contribute to rural development under these conditions.

In Ukraine, 6.5 million hectares of agricultural land characterized by heavy clay soil could be available for sustainable bioenergy crop cultivation because they are considered marginal for food crop cultivation. This study investigated the biomass dry matter yield (DMY) of willow (Salix triandra L. and Salix viminalis L.) and Miscanthus (Miscanthus × giganteus Greef et Deuter) at two experimental sites with heavy clay in Ukraine. To promote plant rooting and adaptation in the first year of cultivation under low‐input conditions, tillage, moisture‐retaining agents, foliar fertilization, planting density and row spacing were varied. Willow obtained notable DMY on hard clay soils (clay >50%). The variety ‘Tora’ revealed the best DMY performance, indicated by the highest increment (4.1–4.6 m) in the first year of the second cycle. The highest biomass DMY (28.8 Mg ha⁻¹) was obtained at a planting density of 15 000 plants ha⁻¹ and a row spacing of 0.75 × 1.50 m. However, neither willow nor Miscanthus allow for a feasible biomass production at clay contents above 64%, because the young roots are damaged and deprived of nutrients as the soil dries out. For Miscanthus, plowing provided better soil loosening and easier sprouting of rhizomes compared with mini‐till. The application of moisture‐retaining agent Aquasorb (200 kg ha⁻¹) supported Miscanthus plants with moisture in the first year of vegetation, but it did not maintain soil moisture in the long term. Therefore, growing willow and Miscanthus on soils with clay contents above 64% is not feasible because the soil texture and tendency to crack significantly reduce the DMY. © 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

Emissions of carbon dioxide (CO₂), nitrous oxide (N₂O), and methane (CH₄), particularly those from organic soils, need to be reduced in the context of climate change mitigation (CCM). Here, we estimated the greenhouse gas (GHG) fluxes from nutrient-poor organic soils in cranberry (Vaccinium macrocarpon) and highbush blueberry (Vaccinium corymbosum) plantations established on former peat extraction fields compared to active peat extraction fields and pristine raised bogs in Latvia. A two-year study (2016–2018) was conducted using the manual closed chamber method. In berry plantations and active peat extraction fields, annual net CO₂ fluxes contributed the most to total GHG emissions, accounting for over 67%, and temperature had the most significant impact on CO₂ fluxes. Conversely, annual CH₄ fluxes were the primary contributor to total net GHG emissions in the pristine raised bog, which simultaneously acted as a slight CO₂ sink. N₂O fluxes were relatively low among all studied land use types. This study provided quantitative insights into the variation in GHG fluxes and the environmental variables influencing them, and the obtained data are valuable to estimate the impact of the establishment of berry plantations on former peat extraction fields on CCM in the hemiboreal region of Europe.

Purpose. To determine mathematical models suitable for yield prediction of bioenergy crops and to establish the patterns of the crop health monitoring. Methods. Field studies were conducted in the zone of unstable soil moisture (Experimental Field of the Institute of Bioenergy Crops and Sugar Beet NAAS of Ukraine, Ksaverivka Druha, Kyiv region) and sufficient soil moisture (Yaltushkiv Experimental Breeding Station of the IBCSB NAAS of Ukraine, Chereshneve, Vinnytsia region) in the Right-Bank Forest Steppe of Ukraine in 2022−2024. Results. Frosts can destroy new giant miscanthus sprouts and reduce crop yield by 15.5% in the sufficient soil moisture zone and by 22.4% in the unstable soil moisture zone. Additionally, under the conditions of unstable soil moisture, yield formation of giant miscanthus is limited by insufficient soil moisture, as miscanthus plants can efficiently use only 20 kg/ha of nitrogen fertiliser. In this case, the yield of giant miscanthus can be predicted using the equation: y = 15.19 + 0.29X – 0.005X². Meanwhile, under the conditions of sufficient soil moisture, small doses of fertilisers do not limit the linear biomass growth function, and the equation for yield prediction is: y = 18.44 + 0.25X. Conclusions. For yield prediction in the specific region, it is advisable to use the regression model proposed by Vossen, which takes into account the average yield, linear time trend, and linear regression function. For a specific agroclimatic region, the potential yield of bioenergy crops could be determined by a formula that considers the total land area of the region, the share of bioenergy plantations, and the predicted yield for the specific conditions of the region. Yield prediction model for bioenergy crop consists of the following levels: (1) determining the areas of bioenergy plantations in the GIS map of the region, specifying the plantation age and the varieties used; (2) refining environmental conditions (soil type, moisture regime, and mineral nutrition); (3) weather observation; (4) vegetation index observation; and (5) yield modelling.

Within this study, we evaluated the fine root (trees and understory vegetation combined) morphological traits, fine root production (FRP), and carbon (C) input with fine root litter in forest stands (dominated by either coniferous or deciduous trees) and clearcut areas (previously dominated by coniferous trees) with nutrient-rich organic soils. The study was conducted in 26 sites in hemiboreal forest land in Latvia and summarizes the results obtained in a two-year study (2020–2022) using the root ingrowth method. Traits and production of fine roots varied significantly depending on forest development stage (stand or clearcut area), dominant tree species type (coniferous or deciduous), and soil drainage status (drained or naturally wet). According to the results of the second study year, mean FRP among groups of study sites varied from 0.58 ± 0.13 to 1.38 ± 0.28 t ha⁻¹ yr⁻¹, while C input with fine root litter ranged from 0.28 ± 0.06 to 0.68 ± 0.14 t C ha⁻¹ yr⁻¹. More than half (59 ± 4%) of the total FRP occurred in the upper 0–20 cm soil layer. FRP tended to correlate positively with soil C/N ratio and negatively with soil pH and soil nutrient concentration. Incubating ingrowth cores for at least two years is strongly recommended to accurately estimate annual FRP and C input. This helps to avoid potential underestimation that may occur when using results of only one incubation year (12 months after ingrowth core installation). This study provided new insights into the dynamics and traits of fine roots and will help to improve the accuracy of C flow estimation in hemiboreal forests with nutrient-rich organic soils in Latvia.