Digestate is a residue of the anaerobic decomposition of organic waste for biogas extraction, but it can be reused as a source of nutrients. To examine the effect of digestate in kohlrabi production, field experiments were conducted during three seasons in two calendar years. The fertilization treatments included the application of solid digestate (two rates—DS1 and DS2), liquid digestate (two rates—DL1 and DL2), solid manure (two rates—MS1 and MS2), and mineral fertilizer (NPK) and were compared with a plot without fertilization (Ø). The results showed a significant increase in the yield with the use of solid and liquid digestate, as well as with NPK, in all growing seasons, while the microelement contents (Zn, Mn, and Cu) in the leaves were at optimum level. The applied treatments did not increase the plant-available nutrients (AL-P₂O₅, AL-K₂O, Fe, Cu, and Zn) in the soil (except Mn). The application of DL2, MS1, and MS2 led to a higher Pb content in kohlrabi stems compared to the control, but the Pb content remained below the maximum permitted limit. Our research showed that digestate can be used as a valuable source of nutrients for kohlrabi production, with a low risk of soil and plant contamination by heavy metals. However, the control of soil, digestates, and manure quality is recommended.

The benefits of nature-based solutions to address the climate and biodiversity challenges have become widely acknowledged. In numerous ways, nature-based solutions align with the Sustainable Development Goals. Serbia, like many other countries, faces many negative impacts of climate change crises. In order to meet sustainable development goals linked to water pollution and biodiversity, we investigated the potential of two plants, namely, Iris pseudocorus L. and Juncus effusus L., and tested for zinc reduction, previously found as an emerging contaminant of urban waters in Serbia. We focused on the investigation of native Serbian plants, that are reported as highly valuable and endangered. Results confirmed that both plant species have high accumulation capacity for Zn uptake, whereas growth and resistance were higher for Juncus effusus L. plants. While the concentration of zinc in Iris plants ranged from 45.85 mg/L to 193.05 mg/L, the concentration found in Juncus plants ranged from 36.2 mg/L to 264.59 mg/L for leaves and 53.20 mg/L for roots. This study contributes to the support for achieving the Sustainable Development Goals in Serbia within biodiversity conservation and sustainable water management, by providing information of plant species that can be included in future sustainable nature-based solutions projects, like bioretention systems and constructed wetlands.

Modern agricultural practices increasingly threaten soil quality, prompting growing interest in organic farming as a sustainable alternative. This study evaluated the effects of organic management on soil fertility and quality in comparison to conventional and undisturbed systems, focusing on fertile Chernozem and less favorable Stagnosol soils. A minimum data set of indicators was used, including bulk density (BD), soil organic carbon (SOC) content and stock, hot water extractable organic carbon (HWOC), and enzymatic activities (dehydrogenase and urease). An integrative statistical framework (blocked ANOVA and PCA) was applied to examine interactions between soil properties and different management practices, while Pearson’s correlations were employed to explore relationships within the organic system. Organic management improved soil quality in two soils, with pronounced benefits in Stagnosol, even after 5–10 years. Conventional production systems exhibited lower biological activity, poorer chemical properties, and higher BD. Long-term organic management (>10 years) in Chernozem enhanced soil quality levels approaching those of undisturbed pasture, while medium-term organic systems showed transitional characteristics. Sensitive indicators such as BD, SOC and HWOC detected early changes in Chernozem, with enzyme activities providing additional insight in Stagnosol. However, SOC stock did not differ significantly between organic and conventional systems due to BD influence. Overall, these findings emphasize the importance of organic farming practices, especially for less fertile soils, and support the use of integrated indicators for soil quality assessment.