• Energy Research
• 2021-2025close
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Eucalyptus is the main fast-growing tree for biomass production in the tropics, providing resources for pulp and paper industries and bioenergy. The potential productivity of forest sites over an eight-year rotation in Brazil was evaluated by the Physiological Principles in Predicting Growth (3-PG) model for two soils, Acrisols and Arenosols, with high and low water storage, respectively, and distinct productive potential capacity. The model was parameterized by data-sets obtained in bimonthly forest inventories performed in stands with 33, 58 and 89 months-old trees, and edaphic surveys. The average volumetric productivity of wood and biomass of the main stem determined at the 89 months-old stand was 374 m3 ha−1 (177 Mg ha−1) for Acrisols and 272.3 m3 ha−1 (130.0 Mg ha−1) for Arenosols. The estimated volumetric production in the Arenosols had a high mean annual increment up to the age of 58 months, with a significant reduction in growth rates after this time. In Acrisols, high incremental rates in wood volume up to age of 89 months (MAIVW > 50 m3 ha−1 year−1) indicate that, under ideal soil conditions, the cutting cycle may exceed 8 years with no productivity impairment. The parameterized model matched well for forest yield (r2 > 0.9) and dendrometric variables (r2 > 0.78). The expected results of lower productivity in Arenosols occurred only after 58 months, while for Acrisols productivity remained high up to 89 months. The results showed the eucalyptus cycle should be shorter in Arenosols, since the lower cutting cycle can provide higher final productivity, when using the mean annual increment to evaluate productivity.

Cassava utilisation in Malawi is negatively affected by rapid deterioration of fresh roots, primarily caused by postharvest physiological deterioration (PPD). A study was conducted to assess farmers’ knowledge and approaches used to minimize losses from PPD. Multi-stage sampling was used to identify districts, Extension Planning Areas (EPA’s) and farmers. Data were collected from 519 farmers using a structured questionnaire. Results revealed that PPD (74.0%) was the major post-harvest constraint followed by pests and diseases (62.1%). Farmers had varying knowledge levels on signs and causes of PPD. They were knowledgeable on PPD signs with 91.5% ably identifying PPD through change of pulp colour. The farmers also had moderate knowledge on causes of PPD, citing high temperature (57.6%) and over-staying of roots (56.2%) as main causes of PPD. Key methods for preventing PPD are: storage (43.0%) and piece-meal harvesting (40.4%). Only 2.6% of the farmers exploited varietal difference in dealing with PPD as some varieties (Sauti, Mpuma, Ching’amba, and Kalasa) take three to five days before showing PPD signs. Farmers’ knowledge levels and PPD preventive methods could be strengthened through: provision of training on post-harvest handling, improvement in storage and processing technologies; and application of advanced breeding techniques to exploit genetic variation in cassava germplasm.

Although the concept of the blue economy was created by the Small Island Developing States, its relevance extends to any coastal region around the globe, making the engagement of both state and corporate actors imperative. At the core of the blue economy framework stands the incorporation of ocean values and services into economic modeling and governance. Sustainable fisheries and aquaculture are thus significant in this endeavor, particularly for Arctic nations, the economies of which are predominantly based on seafood production. Yet, while focus is increasingly placed on sustainability and blue economy models among Arctic states, the need for structured transnational collaboration is not always acknowledged. In that respect, this article aims to articulate a comparative study of the status quo, challenges, and opportunities of fisheries and aquaculture in Alaska and northern Norway and seeks to explore potentials for cross-sectoral synergies between the two regions in the context of the blue economy.

Since habitat fragmentation results in species losses worldwide, considering the influence of buffer zones on the maintenance of connectivity provides a new perspective for buffer delimitation. In our study, the implications of buffer zones around nature reserves were studied at four sites in Fuzhou from the perspective of landscape connectivity based on a distance threshold of 1 km. We applied Graph-based connectivity indices at the landscape level and patch level to reveal the overall connectivity and patterns of change in patch importance for maintaining connectivity with various buffer zones. Based on the results of these analyses, we showed the relationship between structural factors and changes in patch importance by Spearman correlation analysis and redundancy analysis. The results indicate that in the sites with smaller habitat proportion (HP), the connectivity is relatively lower, and the changes in patch importance will be greater when the buffer zone increases. Different buffer zone sizes are suggested in four sites to maximize its benefits. Relatively small patches with high shape complexity and close proximity to patches outside the boundary contribute greatly to connectivity by acting as stepping stones.

This study aims to compare the grain yield, gross return above fertilizer cost (GRAFC: (paddy sales)–(fertilizer cost)), and several parameters relating to the quality of white rice cultivated with different soil-specific nutrient management in 14 provinces where different soil types are distributed. The grain yield tended to increase with increased fertilizer application; however, the relationship between the fertilization rate and the yield was not linear in areas where clay soil dominates. In cases of popular varieties cultivated from the northern to southern province, the amount of fertilizer applied was up to 163 kg ha−1 (sum of N-P2O5-K2O), and the GRAFC and the fertilization rate showed a nonlinear relationship, with a peak of around 120 kg ha−1 fertilization. The nitrogen concentration recognized as a negative factor for the quality of rice tended to increase with an increasing fertilization rate, and the carbohydrate concentration and carbohydrate/protein ratio that are a positive factor for the quality were related negatively with the fertilizer rate. The amylopectin concentration in white rice was positively related with the carbohydrate concentration, which decreased with an increasing fertilization rate. The levels of fertilizer application required to achieve a higher yield, GRAFC, and the maintenance and improvement of parameters relating to grain quality were different.

In Mexico, dry forests are one of the ecosystems in major need of restoration intervention. Here, we explored the ecological and social limitations on the restoration of Mexican dry forests from the perspective of restoration practitioners and researchers. We included three data sources: (i) projects included in a national evaluation (1979–2016), (ii) a systematic review of scientific literature (1979–2021), and (iii) restoration projects included in two governmental programs. The national evaluation and the systematic review coincided in identifying the establishment of plantings as the most important ecological limitation and low social participation as the most important social limitation. There were three times more publications addressing ecological limitations than those addressing social limitations. We did not find research to resolve the problems faced by practitioners related to invasive species, unpredictable climate, and poor soil quality. Governmental programs promoting the restoration of ecosystems need to include measurable indicators to document the socioecological limitations faced by local practitioners to restore Mexican dry forests.

Marine litter has had a huge impact on the marine environment and the socio-economic activities that depend on healthy oceans. All members of the community must play their part to address marine litter. Teachers are agents of change that are capable of encouraging pro-environmental practices among the community that will reduce environmental issues, including marine litter. However, teachers were found to have limited knowledge regarding ocean literacy and marine pollution. A scoping review was conducted to identify various aspects of content knowledge related to marine litter education that has been recently conducted for school teachers and students. Web of Science, Scopus and ERIC databases were searched for articles published in English between 2015 and 8 July 2021. Fourteen peer-reviewed articles were selected for this study and were subjected to content analysis. Topics related to marine litter were frequently addressed. Meanwhile, topics related to teaching Environmental Education/Education for Sustainable Development (EE/ESD) were the least addressed. Benthic marine litter, solutions to marine litter and the introduction of new types of marine litter were identified as topics that need to be addressed in future marine litter education. This study lists content knowledge based on previous literature and identified the gaps, which will be useful for teachers to improve their knowledge and implement effective marine litter education in school.

This study investigated the comparative cultivation of six medicinal plant species (sage, oregano, rosemary, lavender, thyme, and mint) in a dynamic agrivoltaic (AV) system and a neighboring control plot exposed to full sun (referred to as “T”). Specifically, within the dynamic AV system, two distinct plot areas on the ground were identified due to the rotation of the panels: one consistently in the shade of the solar panels (UP), and another alternately in shade and sunlight (BP). The study involved the measurement of solar radiation, air temperature, and infrared leaf temperature during crop growth in these designated plots. Additionally, a weed survey was conducted at harvest time. The findings revealed that solar radiation, air temperature, infrared leaf temperature, and weed coverage were notably lower in the UP plot compared to both the BP and T plots. Furthermore, the yield of essential oils in sage, thyme, mint, and rosemary plants was higher in both the UP and BP plots than in the T plot. Hence, these factors seemingly positively impacted the performance of specific medicinal crops within the dynamic AV system. This information holds significance for producers and processors concerning crop quality.

This study reports the quantification and analysis of the ecosystem services (ESs) value of Posidonia oceanica (L.) Delile (1813) meadows in Italy (Liguria, Tuscany, Latium, Campania, Calabria, Apulia, Sardinia, and Sicily regions). The ES evaluation method of P. oceanica meadows applied in this study was obtained from a previous study in which the site-specific approach for the definition of the benefits and services was applied. The distribution of P. oceanica and the ESs economic value have been managed through an open-source geographic information system (QGIS), focusing on five essential ESs: carbon sequestration, bioremediation, oxygen production, erosion protection, and food production. The average value of the ESs obtained on the Italian national scale is €21,660.5 ha−1 yr−1, which is comparable with the values reported in the international literature concerning P. oceanica ESs. The results of this study confirm that the economic evaluation of ESs is an essential tool for the management of the coastal marine environment, especially considering the modularity of the applied approach. The value of the total benefits, considering the entire extension of the national P. oceanica meadows, represents significant value with respect to the Italian gross domestic product, and the individual budgets of the considered Italian regions.

Savanna woodlands make a significant contribution to rural households’ livelihoods, providing a wide range of resources as well as generating income. However, the sustainability of the woodland ecosystem is generally affected by the human harvesting intensities. This study aimed at quantifying the woodland resource extraction rates and its effects on woodland structure and density. Data were collected from households using a semi-structured questionnaire, key informant interviews, and from 128 rectangular plots measuring 30 m × 30 m. Vegetation parameters, such as tree density, tree height, diameter at breast height, species, stump density, and stump diameter, were recorded. The results of the study revealed that a total of 649 woody stumps were recorded, with an average of 56 trees removed per hectare. The findings showed that the intensities of stumps varied widely, with a high number of stumps recorded at a distance of 10–15 km from the settlements, where major land-use activities are fuelwood extraction, cultivation, and livestock farming. The results also showed that the increased commercial fuelwood production led to cutting of large mopane trees, which is an indicator of unsustainable harvesting. Based on the harvest rates provided by the respondents, results showed that large quantities of fuelwood were harvested for trading, which could put pressure on the woodland ecosystem, consequently resulting in woodland degradation. This study provides forest and range resource managers with valuable information on the quantities of stumps as an indication of tree removals and could be useful in developing effective monitoring strategies and promoting sustainable forest and woodland management.