• Energy Research

Espresso coffee grounds constitute a residue which is produced daily in considerable amounts, and is often pointed out as being potentially interesting for plant nutrition. Two experiments (incubations and field experiments) were carried out to evaluate the potential nitrogen (N) and phosphorus (P) supply for carrot (Daucus carota L.), spinach (Spinacea oleracea L.) and lettuce (Lactuca sativa L.) nutrition.Immobilisation of nitrogen and phosphorus was detected in all the incubations and, in the field experiments, germination and yield growth were decreased by the presence of espresso coffee grounds, in general for all the species studied.The study showed an inhibition of N and P mineralisation and a reduction of plant germination and growth. Further research is required to determine whether this is related to the immobilising capacity of the residue or possibly due to the presence of caffeine.

Sustainable nitrogen (N) management in agriculture is one of the most important issues affecting the environmental performance of modern agriculture. It is actually well perceived that coordinated efforts and holistic approaches are required to regulate N use by farmers. The purpose of this study was to provide an initial examination of stakeholders’ views in Japan regarding N use in agriculture and challenges to increase its sustainability. The analysis was based on a questionnaire study of five types of stakeholders (farmers, advisors, researchers, suppliers, policy makers). By means of multivariate analysis techniques it was revealed that consensus was lacking either in the acknowledgment of the causes and effects of unsustainable N management or in the challenges that need to be addressed. N losses from farms and the effects of N use were perceived but not conceived equally by all stakeholders. Organic farming and mandatory measures were the most controversial challenges, while those involving awareness, training and advisory were the most popular. This study cannot provide safe conclusions that can be generalized in the Japanese context, but it indicates domains where further research is required and orientations for future policy design towards more sustainable N use.

In soils impacted by mining activities a vegetal cover is required to protect the site from the erosive forces of water and wind. The success of this objective depends on plant establishment and canopy closure. Polyacryalate polymers aid the growth of crops and indigenous plants in soils from sulfide mines. Soil characteristics change as a consequence of polymer application, but indicators that pinpoint these changes have not been identified yet. Our objectives were to (1) identify the sensitive indicators of changes in soil quality following polymer application, (2) relate these with assessment based on plant growth and soil cover. A mine soil was left unamended or received a characterized polyacrylate, a polyacrylate removed from diapers, or shredded diapers. Biomass of Spergularia purpurea was measured and proportion of soil cover evaluated. Soil enzymes, microbial activity, and respiration were analyzed. Availability of potentially toxic trace elements was estimated by their concentration in shoots. Factor analysis identified three factors that accounted for 94% of the variation in parameters, and the scores separated the four treatments. The indicators with greatest communality were correlated with plant growth and soil cover. The best soil quality indicators were As and Zn in shoots, protease, β-glucosidase, and fructose-induced respiration. It seems that the most important indicators to be used to assess the restoration of sulfide mine soils are those related with bioavailability of trace elements and soil enzymatic activities.

Soil amended with biochar is considered a significant response to climate change, remediation of degraded soils, and agronomic improvements. An artisanal mobile pyrolysis kiln was developed for small-sized biomass inputs. Approximately 190 kg of biochar was produced in 21 carbonisation processes using acai residues (Euterpe oleracea Mart.) as raw material, as they are among the most abundant agro-industrial residues in the Amazon. It is a valuable and underutilised biomass resource, often inadequately discarded, causing environmental impact and health risks. The physicochemical and structural characteristics of four representative biochar samples from the pyrolysis processes were evaluated using different techniques. The produced biochar had an average pH of 8.8 and the ICP-OES results indicate that the most abundant elements were potassium (K) and phosphorus (P). Results of the elemental composition indicate that the produced biochar has a very stable carbon with an average H/C ratio of 0.23 and O/C ratio of 0.16, indicating that the pyrolysis performed was effective in transforming organic and volatile compounds into stable structures. Variations in nutrient contents call for soil application planning, as performed for other agricultural inputs. The developed mobile kiln can be adapted and favour the decentralisation of biochar production among small and medium-sized producers. Here, we show that even with variations in artisanal production, the biochar produced exhibits favourable characteristics for agronomic use and combating climate changes.

In the present work, two downstream processes - high-pressure homogenization at 100 (HPH-100) and 1200 bar (HPH-1200), and enzymatic hydrolysis (EH) - were tested to produce biostimulant extracts from Tetradesmus obliquus grown in piggery wastewater at two concentrations (12.8 and 88.3 g/L). Extracts before and after centrifugation (C) were evaluated in four bioassays using garden cress (germination), mung bean (auxin-like activity), and cucumber (auxin- and cytokinin-like activity) relative to distilled water. The initial microalgal culture, without any treatment, had the best germination results (162 % at 0.2 g/L) and the only one that showed cytokinin-like activity (141 % at 0.5 g/L). In both auxin-like bioassays, the HPH-1200 + C and EH + C originated high values (186 and 155 % for cucumber, 290 and 285 % for mung bean, respectively). For mung bean, the HPH-1200 achieved the highest auxin-like effect (378 %). Finally, the extracted biomass contained essential nutrients for biofertilization, complementing the biostimulant extracts for sustainable agriculture application.

Good soil quality implies the maintenance of properties at levels capable of ensuring an equilibrated and healthy ecosystem, with sustained agricultural production to supply the world population. Climate change, land-use change, and agriculture intensification are causing a decline in soil quality, which in most parts of the world is becoming severe (desertification). Land-use changes, the associated loss of soil organic matter (SOM), and beneficial microbial diversity are major reasons for deteriorating soil fertility and declining agricultural productivity, as well as affecting water, air, and biodiversity. Adaptation towards climate-resilient and climate-smart agriculture is necessary to cope with climate change and extreme events. This requires the following measures: (1) sustainable production (integrated livestock and cropping systems, including agroforestry); (2) increased soil organic matter (SOM) (bio-based and organic fertilizers, crop rotations, crop associations, no-till, conservation agriculture, C sequestration, and microbial processes); (3) reduced greenhouse gas emissions, less nutrient losses from agriculture, and increased nutrient use efficiency (NUE) (precision agriculture).

Abstract Background The impacts of climate change on crop and livestock sectors are well-documented. Climate change and its related events (e.g., high temperatures, extreme events, disease outbreaks) affect livestock production in various ways (e.g., nutrition, housing, health, welfare), and tend to compromise the physical productivity and the economic performances. Understanding animal responses to climate change may help planning strategies to cope with the adverse climatic conditions and also to reduce polluting emissions. Through an interdisciplinary approach, we develop a conceptual framework to assess and develop new organisational models for Mediterranean small-scale farming systems so as to mitigate the impacts of climate change, to improve farm management and farming technologies, and to achieve an effective adaptation to the climate changes. The conceptual framework consists of four phases: (i) community engagement, (ii) strategies development, (iii) data collection and analysis, (iv) business model generation and sustainability assessment. We assess strengths, weaknesses, opportunities, and threats of the eco-solutions by mean of a SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis technique. Results The proposed eco-solutions are expected to increase the sustainability of agriculture and food production systems by introducing new and efficient uses of natural resources. The proposed models are expected to have an impact not only on the environment (in terms of mitigation), but also on the economic and social performances, as they are expected to foster the responses of small-scale farms to the increasingly frequent effects of climate change (adaptation solutions). Among the positive impacts, we emphasise the importance of more stable revenues, a tendency that would help farmers to raise their revenues. Last but not least, we found that the proposed models are likely to increase the social resilience of the farming systems to the challenges imposed by the climate change. Conclusions The eco-solutions can support stakeholders involved in Mediterranean small-scale farming systems by suggesting novel land, crop, and livestock management approaches to optimise revenue flows, business models and climate change mitigation strategies thanks to the adoption of a systemic approach, that is not only focused on specific components of the system but instead based on the linkages between environmental, social, and economic aspects.