**1. Introduction**

In the targeted 'ideal' bioeconomy, the production of biomass will take social, ecological, and health aspects into account [1] to help achieve the sustainable development goals 2015–2030. From the bioeconomy's ambitions and definitions, conclusions can be drawn that the growth of the bioeconomy demands both a reduction of waste and losses and an adequate supply of sustainably grown biomass [2]. However, an increasing biomass production also carries a higher risk of social-ecological threats, such as increased use of fertilizers and pesticides, negative impacts from land-use changes and additional pressure on water resources [3–5]. The EU Horizon 2020 project MAGIC (Grant agreemen<sup>t</sup> ID: 727698) was established with the ambition of supporting the mitigation of these risks. This study deals with the basic findings of the 'Low-input agricultural practices for industrial crops on marginal land'.

Low-input agriculture (Figure 1) generally provides a number of promising practices that can help improve the social-ecological sustainability of biomass production while maintaining economic feasibility [6]. Here, a key parameter is the ratio between on- and o ff-farm inputs. According to Biala et al. (2007) [6], in low-input agriculture, the use of on-farm inputs should be maximized and o ff-farm inputs minimized. Currently, there are four concrete and real farming system types which follow these low-input agriculture principles (taken from Reference [7]): (i) Integrated farming, (ii) organic farming, (iii) precision farming, and (iv) conservation farming.

**Figure 1.** Principles of low-input agriculture (Source: This study).

For each of these farming systems, crop selection was found to be highly relevant for efficient use of resources during their cultivation [8–11]. The resource use efficiency becomes even more relevant for industrial crop cultivation on marginal agricultural lands (Figure 2). This is because both the yield potential and the resilience of the agro-ecosystems (their robustness against cropping failures) may be lower on marginal agricultural lands compared to fertile agricultural lands [9,12–17]. According to Elbersen et al. [12], marginal agricultural lands can be defined as '*lands having limitations which in aggregate are severe for sustained application of a given use and*/*or are sensitive to land degradation, as a result of inappropriate human intervention, and*/*or have lost already part or all of their productive capacity as a result of inappropriate human intervention and also include contaminated and potentially contaminated sites that form a potential risk to humans, water, ecosystems, or other receptors'*. The implementation of a low-input approach that can potentially reduce the risk to humans, water, ecosystems or other receptors is mainly dependent on the farming system and requires site-specific consideration [18,19].

**Figure 2.** Illustration of relevant biophysical constraints and both economic and social-ecological challenges selected for marginal agricultural land low-input systems (Source: This study). Numbers 1–7 indicate the major biophysical constraints on marginal lands as defined by the Joint Research Centre (JRC) [20–22]. The other parameters either influence (main constraints) or follow on (combined constraints) from the major biophysical constraints, which limit the site-specific plant growth suitability (Table A1). The economic and social-ecological challenges have been added, due to their increasing relevance for modern agricultural systems [23–26]. These challenges can render a site marginal under both economic and social-ecological aspects, such as environmental protection, biodiversity conservation, infrastructure, markets and landscape appearance.
