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Eficiência energética do agroecossistema estufa plástica numa perspectiva agroecológica.

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Hoppe , Marcelino (2002) Eficiência energética do agroecossistema estufa plástica numa perspectiva agroecológica. [Energy efficiency of a greenhouse agroecosystems agroecological perspective.] Masters thesis, Universidade Federal de Pelotas , Faculdade de Agronomia Eliseu Maciel. .

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Summary

0 cultivo convencional em estufa plastica e um agroecossistema cujas limitacoes (clima e solo) podem ser superadas proporcionando rendimentos maiores que a campo. Porem, sofre criticas e tem sido apresentado como de balanco energetico negativo. O presente trabalho, realizado na UFPel em estufa plastica (7,8m x 39,4m) coberta com polietileno (0,15mm), avaliou a eficiencia energetica do cultivo do meloeiro (Cucumis melo L.) numa erspectiva agroecologica, contabilizando as entradas e saidas de energia. Os efeitos das adubacoes organica e mineral foram avaliados com oito tratamentos (parcelas de 6,0m2) e tres repeticoes. A mao-de-obra representou 100 h.homem'1.mes'1, ou 50% da carga mensal de trabalho do agricultor. Os gastos energeticos na adubacao mineral (268,95 kcal.m'2) e organica completa (255,12 kcal.m'2) foram semelhantes. O menor custo do adubo organico foi onerado pelo maior gasto em frete e aplicacao. A produtividade de melao não apresentou diferenca significativa ao nivel de 5% entre os tratamentos. O tratamento adubacao organica completa produziu 3,978 kg.m 2 e o tratamento adubacao mineral 3,060 kg.m'2. A produtividade media (da terra) foi de 3,12 kg.m'2 e da mao-de-obra foi de 4,52 kg.melao.h'1.homem'1. A eficiência energetica do sistema foi negativa, pois, para cada 1 kcal investida foi obtida em media 0,18 kcal de melao ou 0,45 kcal de biomassa total. A maior eficiência. foi obtida pelo tratamento adubacao organica completa: 0,23 para frutos e 0,53 para biomassa total. Os resultados permitem inferir que o aumento da eficiencia do agroecossistema estudado passa pela substituicao do substrato comercial por substrato alternativo a exemplo do solo, areia e vermicomposto, e do mulching com polietileno por palha, papel ou plastico reciclado, pois estes itens representaram 48% do consumo energetico na producao de melao. A reciclagem de materiais pode aumentar a eficiencia: materiais metalicos da estrutura (13% do insumo total medio) e plastico de cobertura (10% do insumo total medio) se prestam para esta finalidade. Uma economia de 23% no plastico pode ser obtida com o uso de lamina inteirica ao inves de laminas traspassadas. A substituicao do fitilho de polipropileno e adubo mineral por sisal e adubos organicos pode ser interessante, pois mesmo nao representando grande economia energetica sao renovaveis e de baixo custo ambiental. A producao dos adubos organicos na propriedade gera economia no gasto com frete. A eficiencia pode ser aumentada sensivelmente, pois os insumos podem ser reduzidos a menos da metade do custo atual.

Summary translation

The cultivation in a polyethylene greenhouse is a agroecosystem which restrictions (climate and ground) can be exceeded, providing more profit than in the field. Although, suffers criticism and have been presented as a negative energetic balance. This study was achieved in UFPel in polyethylene greenhouse (7.8m x 39.4m) valuated the energetic efficiency of the melon cultivation (Cucumis melo L.), on agroecologycal perspective, counting the inputs and outputs of energy. The effects of the mineral and organic fertilization were valuated with eight treatments (in plots of 6.0m2) and three repetitions. It took 100 h.manVmonth'1, or 50% of the farmer’s month load labor. The energetic expenses in mineral fertilization (268.95 kcal.m'2) and organic (255.12kcal.m'2) were similar. The least cost of the organic fertilizer was overloaded by the greater cost of freight and application. The productivity of melon didn’t show any important difference in the levei of 5% among the treatments. The complete organic fertilizer treatment produced 3.978 kg.m-2 and the mineral fertilizer treatment 3.060 kg.m'2. The average of productivity (of the land) was 3.12 kg.m' 2 and the labor one was 4.52 kg.melon.h'1.man'1. The energy efficiency of the system was negative, because, for each 1 kcal invested was gotten an average of 0.18 kcal of melon or 0.45 kcal of total biomass. The greatest efficiency was gotten by the complete organic fertilizer treatment: 0.23 for fruits and 0.53 for total biomass. The results aloud knowing that the increase of the efficiency of the agrosystem studied passes by the substitution of commercial substrate for alternative substrate (soil, sand and earthworm compost) and the mulching with polythene for straw, paper or recycled plastic, because this items represent 48% of the energetic consumption in melon production. The recycling of materiais can increase the efficiency: metallic materiais of the structure (13% of the total consumed) and plastic for covering (10% of the total consumed) are known for his usage. An economy of 23% on plastic can be gotten with usage of full sheet in place of trespassed sheet. The substitution of polypropylene band and mineral fertilizer for sisal and organic fertilizer can be interesting, because, even not representing big energetic economy are renewed and with a low environmental cost. The production of organic fertilizers on the farm produces economy in the expenses with freight. The efficiency can be really increased because the consumed materiais can have its costs reduced to half.

EPrint Type:Thesis
Keywords:Cucumis melo, Eficiência energética, Energia complementar, Biomassa, Adubação orgânica, Vermicomposto, Cinza de casca de arroz. Cucumis melo, Energy efficiency, Complementary energy, Biomass, Organic adubation, Solid bovine manure vermicompost, Rice hull ash.
Agrovoc keywords:
LanguageValueURI
EnglishCucumis melohttp://aims.fao.org/aos/agrovoc/c_2003
Englishbiomasshttp://aims.fao.org/aos/agrovoc/c_926
Englishagroecologyhttp://aims.fao.org/aos/agrovoc/c_92381
EnglishOrganic fertilizershttp://aims.fao.org/aos/agrovoc/c_4592
EnglishRice huskshttp://aims.fao.org/aos/agrovoc/c_24892
Englishwasteshttp://aims.fao.org/aos/agrovoc/c_7228
EnglishEnergy managementhttp://aims.fao.org/aos/agrovoc/c_24837
EnglishGreenhouseshttp://aims.fao.org/aos/agrovoc/c_3379
Subjects: Farming Systems > Farm economics
Farming Systems
Farming Systems > Farm nutrient management
Research affiliation: Brazil > Other organizations
Deposited By: Santos, Ederson Luiz
ID Code:24850
Deposited On:14 Feb 2014 11:08
Last Modified:14 Feb 2014 11:08
Document Language:Portuguese/Portugues
Status:Published
Refereed:Peer-reviewed and accepted

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