Injustiças da sustentabilidade: Conflitos ambientais relacionados à produção de energia "limpa" no Brasil Este trabalho discute as contradições existentes na implementação de projetos de energia "limpa", a partir de quatro casos do contexto brasileiro: agrocombustíveis via cana-de-açúcar, hidrelétricas, parques eólicos e, por fim, energia nuclear. Todos geram inúmeros impactos sociais, ambientais e à saúde que caracterizam o que denominamos provocativamente "injustiças da sustentabilidade". Assumimos que os conflitos ambientais existentes nos casos são inevitáveis em sociedades de mercado, cuja visão hegemônica de desenvolvimento econômico das corporações e, frequentemente, órgãos de governo é confrontada por populações atingidas e movimentos sociais. Portanto, consideramos estratégico reconhecer as injustiças ambientais como forma de articular as bases materiais da sustentabilidade com questões econômicas, sociais, culturais e filosóficas acerca da noção de progresso.
The objective of this study was to evaluate the growth of ‘jurema-branca’ seedlings (Piptadenia stipulacea (Benth.) Ducke.), irrigated with effluent from fish farming in order to meet the nutritional demand in the initial growth stage. The treatments consisted in the dilution of fish farming wastewater in different concentrations (0, 25, 50, 75 and 100%) with supply water. Seeds were sown in 0.9-L polyethylene bag containing a mixture of soil and manure. At 54 days after sowing the shoot length, stem diameter, height/diameter ratio, number of leaves, leaf area, unit leaf area, dry matter of stem, leaves, shoots, roots and total, chlorophyll content index and Dickson quality index were evaluated. The growth of ‘jurema-branca’ seedlings is favored by the dilution of 25% of fish farming wastewater in the supply water. Using up to 25% of the concentration of the fish farming effluent does not significantly affect the dry biomass accumulation in ‘jurema-branca’ seedlings, in relation to the control. The reuse of fish farming wastewater diluted at proportion of up to 25% is a viable alternative to meet the water demand in the production of forest seedlings.
A B S T R A C TThis study aimed to evaluate the growth of young Tabebuia aurea seedlings irrigated with different concentrations of wastewater from fish farming. The experiment was conducted in a seedling nursery, from June to August 2013. The treatments consisted of five concentrations of wastewater from fish farming diluted in freshwater (0, 25, 50, 75 and 100% of wastewater). Plant height, stem diameter and plant height/stem diameter ratio were evaluated every 15 days to verify the effects of treatments on seedlings growth. At the end of the experiment, individual leaf area, leaf area, leaf dry matter, stem dry matter, root dry matter, total dry matter and Dickson quality index were also evaluated. The reuse of wastewater from fish farming diluted at concentrations of 25 and 50% in freshwater is a viable alternative in the production of Tabebuia aurea seedlings. However, higher concentrations hinder the production of seedlings of this species.Crescimento de mudas jovens de craibeira sob irrigação com água residuária da piscicultura R E S U M O Objetivou-se, neste trabalho, avaliar o crescimento de mudas jovens de craibeira (Tabebuia aurea) irrigadas com diferentes concentrações de água residuária da piscicultura. O experimento foi conduzido em viveiro de produção de mudas, entre junho e agosto de 2013. Os tratamentos foram compostos por cinco concentrações de água residuária da piscicultura diluídas em água de abastecimento (0, 25, 50, 75 e 100% de água residuária). Foram realizadas avaliações quinzenais para verificação dos efeitos dos tratamentos no crescimento das mudas avaliando-se o comprimento da parte aérea, diâmetro do colo e relação comprimento da parte aérea/diâmetro do colo. A área foliar unitária, área foliar, matéria seca das folhas, caules, raízes e total e índice de qualidade de Dickson também foram avaliados ao término do experimento. O reúso de água residuária da piscicultura diluída nas concentrações de 25 a 50% é uma alternativa viável para irrigação de mudas de craibeira sendo que concentrações superiores inviabilizaram a produção de mudas dessa espécie.
The objective of this work was to evaluate the profitability of sweet potato cultivars, harvested at different ages and cultivated in different periods (rainy and dry) in the municipality of Mossoró, semi-arid region of Rio Grande do Norte. The experimental design was a randomized complete block design with four replications and treatments arranged in split plots scheme. The plots were composed of three sweet potato cultivars (ESAM 1, Paraná and Mother of Family) and the subplots for five harvest ages (90 , 105, 120, 135 and 150 days after transplanting - DAT). Productivity of commercial roots and production costs was evaluated, as well as the economic indicators: gross income, net income, rate of return and profit margin. Independently of the growing periods, the productivity of commercial roots increased with the later harvest of the crop and differentiated the cultivars. Production costs averaged R$ 6,087.97 ha-1 in the rainy season and R$ 6,181.42 ha-1 in the dry period. Labor expenditures were the most impacting of total expenditures. The cultivars ESAM 1 and Paraná presented higher productivities of commercial roots and profitability when cultivated in the rainy season, while Paraná cultivar was superior to the other cultivars in the crop in the dry season. In both growing periods, the harvest age of 150 DAT promoted higher productivities of commercial roots and profitability to sweet potato production.
Reusing wastewater for irrigation purposes is a sustainable approach for crop production in arid and semi-arid regions. Nevertheless, this technique requires further study on the response of plants to this type of water. This work aimed at assessing the growth and quality of Handroanthus impetiginosus (pink lapacho) seedlings irrigated with different concentrations of saline fish effluent. We used a randomized complete block design with four replicates and four plants per replicate. Treatments consisted of irrigation with five solutions containing different percentages of saline fish effluent diluted in tap water (0 [tap water], 25, 50, 75 and 100% fish effluent). At 60 days after transplanting, the effects of irrigation with saline fish effluent on the initial growth of seedlings were assessed based on shoot height, leaf number, stem diameter, shoot height/stem diameter ratio, leaf area, individual leaf area, leaf dry weight, stem dry weight, root dry weight, total dry weight, Dickson quality index, shoot height/shoot dry weight ratio and shoot dry weight/root dry weight ratio. The use of saline fish effluent diluted up to 50% of the irrigation water proved to be a feasible and sustainable practice for producing H. impetiginosus seedlings, with no negative effects on total dry weight and Dickson quality index. However, higher concentrations of this effluent caused a significant reduction in shoot height and leaf area.
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