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.

Growing industrial crops on marginal lands has been proposed as a strategy to minimize competition for arable land and food production. In the present study, eight experimental sites in three different climatic zones in Europe (Mediterranean, Atlantic and Continental), seven advanced industrial crop species [giant reed (two clones), miscanthus (M. × giganteus and two new seed‐based hybrids), saccharum (one clones), switchgrass (one variety), tall wheatgrass (one variety), industrial hemp (three varieties) and willow (eleven clones)], and six marginality factors alone or in combination (dryness, unfavorable texture, stoniness, shallow soil, topsoil acidity, heavy metal and metalloid contamination) were investigated. At each site, biophysical constraints and low‐input management practices were combined with prevailing climatic conditions. The relative yield of a site‐specific low‐input system compared with the site‐specific control was from small to large (i.e. from −99% in industrial hemp in the Mediterranean to +210% in willow in the Continental zone), due to the genotype‐by‐management interaction along with climatic variation between growing seasons. Genotype selection and improved knowledge on crop response to changing environmental, site‐specific biophysical constraint and input application has been detected as key to profitably grow industrial crops on marginal areas. This study may act to provide hints on how to scale up investigated cropping systems, through low‐input practices, under similar environmental and soil conditions tested at each site. However, further attention to detail on the agronomy of early plant development and management in larger multi‐year and multi‐location field studies with commercially scalable agronomies are needed to validate yield performances, and thereby to inform on the best industrial crop options.

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.

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.

Âèÿâèòè îñîáëèâîñò³ ðîñòó é ðîçâèòêó ñîðò³â ñî¿ çàëåaeíî â³ä çàñòîñóâàííÿ îðãàí³÷íîãî äîáðèâà, ðåãóëÿòîð³â ðîñòó ðîñëèí òà âîëîãîóòðèìóâà÷à â óìîâàõ ˳ñîñòåïó Óêðà¿íè. Ìåòîäè. Äîñë³äaeóâàëè ñîðòè ñî¿ 'Óñòÿ', 'Êàíî' òà 'úáà'. Çà ì³ñÿöü äî ñ³âáè ñî¿ â ´ðóíò âíîñèëè âîëîãîóòðèìóâà÷-ã³äðîãåëü Àêâàñîðá (Aquasorb) ó íîðì³ 300 êã/ãà ñòð³÷êàìè çàâøèðøêè 10 ñì ó çîíó ìàéáóòíüîãî ðÿäêà. Îðãàí³÷íå äîáðèâî Ïàðîñòîê (ìàðêà 20) çàñòîñîâóâàëè äâ³÷³: ïåðøå ï³äaeèâëåííÿ ó ôàç³ 3-5 ëèñòê³â òà äðóãå-9-11 ëèñòê³â ñî¿. Ðåãóëÿòîðè ðîñòó Âåðìèñòèì Ä ³ Àãðîñòèìóë³í âíîñèëè ó ôàç³ áóòîí³çàö³¿ êóëüòóðè. Ðåçóëüòàòè. Çà ï³äaeèâëåííÿ ñî¿ äîáðèâîì Ïàðîñòîê àñèì³ëÿö³éíà ïîâåðõíÿ ñîðòó 'Óñòÿ' ó ôàç³ öâ³ò³ííÿ ó âàð³àíòàõ áåç âèêîðèñòàííÿ ã³äðîãåëþ Àêâàñîðá ñòàíîâèëà 38,2 òèñ. ì 2 /ãà, òèì÷àñîì ÿê íà âàð³àíòàõ éîãî çàñòîñóâàííÿ ðîñëèíè ôîðìóâàëè 43,6 òèñ. ì 2 /ãà. Ó ñîðòó 'Êàíî' âíåñåííÿ îðãàí³÷íîãî äîáðèâà ñïðèÿëî ôîðìóâàííþ ëèñòêîâî¿ ïîâåðõí³ íà âàð³àíòàõ áåç ã³äðîãåëþ íà ð³âí³ 38,6 òèñ. ì 2 /ãà, à çà éîãî âíåñåííÿ-45,8 òèñ. ì 2 /ãà. Àíàëîã³÷í³ çàêîíîì³ðíîñò³ áóëî îòðèìàíî ³ äëÿ ñîðòó 'úáà'-39,0 òà 44,9 òèñ. ì 2 /ãà â³äïîâ³äíî. Îáðîáëåííÿ ïîñ³â³â äîáðèâîì Ïàðîñòîê ñïðèÿëî ï³äâèùåííþ ð³âíÿ ÷èñòî¿ ïðîäóêòèâíîñò³ ôîòîñèíòåçó â óñ³õ äîñë³äaeóâàíèõ ñîðò³â ñî¿. Òàê, ó ñîðòó 'Óñòÿ' ó âàð³àíòàõ áåç ã³äðîãåëþ éîãî çàñòîñóâàííÿ äàëî çìîãó ñôîðìóâàòè 0,73 ã/ì 2 ñóõî¿ ðå÷îâèíè çà äîáó, òèì÷àñîì ÿê ó êîíòðîë³-0,68 ã/ì 2 çà äîáó. Çà àíàëî㳺þ â ñîðò³â ñî¿ 'Êàíî' òà 'úáà' áóëè îòðèìàí³ ïîêàçíèêè íàêîïè-÷åííÿ ñóõî¿ ðå÷îâèíè íà ð³âí³ 1,00 òà 0,62 ã/ì 2 çà äîáó, à â êîíòðîëüíèõ âàð³àíòàõ-0,92 òà 0,46 ã/ì 2 çà äîáó â³äïîâ³äíî. Âèñíîâêè. Ó ñåðåäíüîìó çà ðîêè äîñë³äaeåíü ðîñëèíè ñîðòó 'Óñòÿ' óòâîðþâàëè 5,6-5,7 ã íàñ³ííÿ íà îäíó ðîñëèíó. Ñîðò 'Êàíî', ÿê ³ 'Óñòÿ', ó ðàç³ çàñòîñóâàííÿ ðåãóëÿòîðà ðîñòó Âåðìèñòèì Ä íà ôîí³ âíåñåííÿ äîáðèâà Ïàðîñòîê (ìàðêà 20) óòâîðþâàâ 8,6 ã íàñ³ííÿ íà ðîñëèíó, à íà ôîí³ çàñòîñóâàííÿ ã³äðîãåëþ Àêâàñîðá-8,7 ã. Ó ðàç³ çàñòîñóâàííÿ ðåãóëÿòîðà ðîñòó Àãðîñòèìóë³í îòðèìàíî ³íäèâ³äóàëüíó ïðîäóêòèâí³ñòü ðîñëèí ñî¿ íà ð³âí³ 8,7 òà 8,5 ã â³äïîâ³äíî. Êëþ÷îâ³ ñëîâà: ñîÿ; îðãàí³÷í³ äîáðèâà; ðåãóëÿòîðè ðîñòó ðîñëèí; âîëîãîóòðèìóâà÷; âðîaeàéí³ñòü òà ÿê³ñí³ ïîêàçíèêè çåðíà; ïîãîäí³ óìîâè âåãåòàö³éíîãî ïåð³îäó; âîëîãîçàáåçïå÷åí³ñòü.