Source-separating sanitation systems offer the possibility of recycling nutrients present in wastewater as crop fertilisers. Thereby, they can reduce agriculture's impacts on global sources, sinks, and cycles for nitrogen and phosphorous, as well as their associated environmental costs. However, it has been broadly assumed that people would be reluctant to perform the new sanitation behaviours that are necessary for implementing such systems in practice. Yet, few studies have tried to systematically gather evidence in support of this assumption. To address this gap, we surveyed 3763 people at 20 universities in 16 countries using a standardised questionnaire. We identified and systematically assessed cross-cultural and country-level explanatory factors that were strongly associated with people's willingness to consume food grown using human urine as fertiliser. Overall, 68% of the respondents favoured recycling human urine, 59% stated a willingness to eat urine-fertilised food, and only 11% believed that urine posed health risks that could not be mitigated by treatment. Most people did not expect to pay less for urine-fertilised food, but only 15% were willing to pay a price premium. Consumer perceptions were found to differ greatly by country and the strongest predictive factors for acceptance overall were cognitive factors (perceptions of risks and benefits) and social norms. Increasing awareness and building trust among consumers about the effectiveness of new sanitation systems via cognitive and normative messaging can help increase acceptance. Based on our findings, we believe that in many countries, acceptance by food consumers will not be the major social barrier to closing the loop on human urine. That a potential market exists for urine-fertilised food, however, needs to be communicated to other stakeholders in the sanitation service chain.

The aim of this study was to assess the effect of a three-year application of digestate from an agricultural biogas plant on the physicochemical properties of highly acidic pH_KCl 4.4 ± 0.23, silty loam soils with low macronutrient content and on the yield and nutritional value of switchgrass (Panicum virgatum L.) biomass harvested for green fodder. The experiment included the following treatments: (1) O (control)—no fertilisation, (2) NPK—mineral fertilisation with (in kg ha⁻¹) 150 N, 53.0 P and 105 K, (3) biogas digestate at 30 m³ ha⁻¹ and (4) biogas digestate at 60 m³ ha⁻¹. The higher application rate of biogas digestate significantly reduced soil acidity to pH_KCl 4.9 ± 0.18 and improved its sorption properties. It also increased the soil organic matter content from 5.6 ± 0.21 to 6.4 ± 0.22 g C_org kg⁻¹ and of K and Zn. The higher level of biogas digestate significantly increased switchgrass yield to 5.15 ± 0.26 t ha⁻¹. The lower application rate of biogas digestate resulted in forage yield of 4.30 ± 0.20 t ha⁻¹ comparable to that obtained after mineral fertilisation (4.33 ± 0.22 t ha⁻¹). Following application of mineral fertilisers and the higher level of biogas digestate, the number of panicles per plant (150 ± 2.49–157 ± 0.6.17), panicle height (107 ± 1.98–114 ± 2.08), crude ash content (61.2 ± 0.43–65.5 ± 0.38) and protein content (106 ± 0.59–92 ± 1.11) in the switchgrass biomass from the first cut were higher than in the case of unfertilised soil (110 ± 3.81, 93 ± 1.32, 55.5 ± 0.40, 80.3 ± 0.37). The use of mineral fertilisers and biogas digestate increased the content of protein, P and Mg in biomass from the second cut. The results suggest that the use of digestate improved the physicochemical properties of highly acidic soil and increased the yield of switchgrass forage without diminishing its nutritional value.

Oils from five cultivars of apricot (Prunus armeniaca L.) grown in Poland were analysed for characteristics of chemical and biological activity. The extracted oils had an average iodine value (g of I/100 g of oil) of 99.2; a refractive index of (40°C) 1.4675; a saponification value of 189 mg of KOH/g of oil; and 0.68% unsaponifiable matter. As regards the oxidation state, the specific extinction values of the oils at 232 and 268 nm were 2.55 and 0.94, respectively, while the peroxide value was 1.40 meq O2/kg and the p-anisidine value was 1.42. Oleic acid (70.70%) was the predominant fatty acid found in the oils, followed by linoleic (22.41%), palmitic (3.14%), stearic (1.4%), linolenic (0.90%), and palmitoleic (0.70%) acid. The content of α-, γ-, and δ- tocopherols in the oils from the five apricot cultivars was 19.6–40.0, 315.4–502.3, and 28.3–58.5 mg/kg, respectively. The antioxidant capacity of the apricot kernel oils, measured using the FRAP assay, ranged from 1.07 to 1.38 mM Fe2+/L, while total polyphenols and β-carotene content were 0.85–1.22 mM gallic acid/L and 42.3–66.8 μg/g, respectively. The results indicate that among the cultivars tested, the ‘Somo’ cultivar grown in Poland provides the most oil, with the highest antioxidant activity. The results of our study demonstrate that apricot seeds are a potential source of oil that can have both dietary and cosmetic applications.

One of the greatest challenges of the 21st century is to obtain an ecological source of transport fuels. The production of biofuels based on feedstock obtained through the exploitation of arable land translates into an increase in food prices and progressive degradation of the environment. Unlike traditional agricultural raw materials, algae are a neutral alternative in many respects. They can even be obtained as waste from polluted water reservoirs. One of the manifestations of the deterioration of surface waters is the eutrophication of water reservoirs, which leads to an increase in the number of algae. Algae reaching the shores of water reservoirs can be used as a raw material for the production of biofuels, including biogas, bioethanol and biodiesel. However, it should be remembered that water blooms are a periodic phenomenon, appearing in the summer months. Therefore, in order to ensure the continuity of obtaining energy from biomass, it is necessary to conduct algae cultivation in artificial open tanks or photobioreactors. Accordingly, this review first briefly discusses the properties and possible applications of different species of algae in various industrial areas, and then describes the process of eutrophication and the presence of algae in eutrophicated reservoirs. Technologies of algal cultivation in various systems and technologies of algal biomass pretreatment were critically discussed. Various methods of obtaining biomass from algae were also reviewed, and the process conditions were summarized. Biofuels of various generations and raw materials from which they are obtained are presented in order to determine the possible future directions of development in this field. Parameters affecting the selection of algae species for the production of biofuels were also examined and presented. Overall, algal biofuels still face many challenges in replacing traditional fossil fuels. Future work should focus on maximizing the yield and quality of algae-derived biofuels while increasing their economic viability.

Both nitrogen and sulphur are important macronutrients necessary for the proper development and yield of soybean. Moreover, sulphur plays a special role in nitrogen metabolism in the plant, and sulphur deficiency leads to a reduction in the utilization of nitrogen from fertilizer. The objective of this study was to assess the effect of nitrogen and sulphur application on the yield and quality traits of soybean seeds. The following factors were analyzed in the experiment: I. Nitrogen application rate: 0, 30 and 60 kg ha⁻¹ applied at different times (before sowing and/or at the start of the seed filling stage); II. Sulphur application rate: 0 and 40 kg ha⁻¹ applied in two portions: half during the development of lateral shoots and half at the start of flowering. Thus the 14 fertilizer combinations were obtained. Result show that the highest seeds yield was obtained in the combinations with 60 kg N applied ½ before sowing + ½ after emergence (BBCH 73-75) and ¾ before sowing +¼ after emergence. In these combinations, sulphur did not significantly affect seed yield. In the remaining nitrogen application, sulphur application significantly increased the seed yield. Taking into account the yield and the chemical composition of the soybean seeds, fertilization with 60 kg N ha⁻¹ in two portions can be recommended—½ or ¾ before sowing and the remainder during the development of pods and seeds—in combination with sulphur application.