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Comparação agronómica e económica de tecnologias alternativas na cultura do arroz
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Resumo(s)
O objetivo desta dissertação é avaliar a viabilidade da produção de arroz com um sistema de rega gota-a-gota comparando com o modelo tradicional por alagamento. Esta comparação tem o intuito de perceber os seus impactos tanto económicos como fitossanitários e ambientais de modo a verificar se existe uma redução significativa na quantidade de água utilizada durante todo o ciclo vegetativo, mantendo ou melhorando o rendimento produtivo do modelo tradicional.
O estudo foi realizado entre abril de 2022 e outubro de 2022 em 2 canteiros, num total de 8,06 hectares, em Pancas. Estes terrenos pertencem à empresa Orivárzea.
O estudo inicia-se com um levantamento da condutividade elétrica aparente e uma análise química dos solos e posteriormente com a implementação da cultura com 3 modalidades diferentes. Num canteiro utilizou-se o sistema de rega gota-a-gota através da sementeira em seco na linha com semente enterrada (com posterior instalação das fitas de rega), este canteiro por não ser alagado permitiu-nos dividi-lo em duas parcelas iguais, onde numa fez-se uma adubação de fundo e na outra não, e no outro canteiro implementou-se o sistema convencional alagado com sementeira a lanço e com adubação de fundo. Após a implementação da cultura seguiu-se o acompanhamento desta de modo a perceber as diferenças que existem quanto ao seu desenvolvimento nas três modalidades. Por fim, foi feito um balanço relativamente aos rendimentos alcançados.
Conseguiu-se alcançar uma poupança de água de aproximadamente 45% do sistema de rega gota-a-gota em relação ao convencional. No entanto, ambas as modalidades do sistema de rega gota-a-gota, apresentaram uma produtividade muito inferior, cerca de metade, comparativamente à modalidade do convencional, sendo que a nível económico não apresentaram viabilidade, contrariamente à modalidade convencional.
The purpose of this dissertation is to evaluate the feasibility of rice production using a drip irrigation system compared to the traditional flooding method. This comparison aims to understand its economic, phytosanitary, and environmental impacts, in order to verify if there is a significant reduction in the amount of water used throughout the vegetative cycle, while maintaining or improving the productive yield of the traditional method. The study was conducted between April 2022 and October 2022 in 2 plots, totaling 8.06 hectares, in Pancas. These lands belong to the company Orivárzea. The study begins with a survey of the apparent electrical conductivity and chemical analysis of the soils, followed by the implementation of the culture with three different modalities. In one bed, the drip irrigation system was used through dry sowing in the line with buried seed (with subsequent installation of irrigation tapes). This bed, not being flooded, allowed us to divide it into two equal plots, where one was fertilized and the other was not. In the other bed, the conventional flooded system was implemented with broadcast sowing and fertilization. After the implementation of the culture, its development was monitored to understand the differences among the three modalities. Finally, a balance was made regarding the yields achieved. It was possible to achieve a water saving of approximately 45% with the drip irrigation system compared to conventional. However, both modalities of the drip irrigation system showed significantly lower productivity than the conventional method and were not economically viable, contrary to the conventional modality.
The purpose of this dissertation is to evaluate the feasibility of rice production using a drip irrigation system compared to the traditional flooding method. This comparison aims to understand its economic, phytosanitary, and environmental impacts, in order to verify if there is a significant reduction in the amount of water used throughout the vegetative cycle, while maintaining or improving the productive yield of the traditional method. The study was conducted between April 2022 and October 2022 in 2 plots, totaling 8.06 hectares, in Pancas. These lands belong to the company Orivárzea. The study begins with a survey of the apparent electrical conductivity and chemical analysis of the soils, followed by the implementation of the culture with three different modalities. In one bed, the drip irrigation system was used through dry sowing in the line with buried seed (with subsequent installation of irrigation tapes). This bed, not being flooded, allowed us to divide it into two equal plots, where one was fertilized and the other was not. In the other bed, the conventional flooded system was implemented with broadcast sowing and fertilization. After the implementation of the culture, its development was monitored to understand the differences among the three modalities. Finally, a balance was made regarding the yields achieved. It was possible to achieve a water saving of approximately 45% with the drip irrigation system compared to conventional. However, both modalities of the drip irrigation system showed significantly lower productivity than the conventional method and were not economically viable, contrary to the conventional modality.
Descrição
Mestrado em Engenharia Agronómica. Universidade de Lisboa, Instituto Superior de Agronomia
Palavras-chave
sementeira em seco rega gota-a-gota adubação de fundo poupança de água produtividade dry sowing drip irrigation basal fertilization water savings productivity
Contexto Educativo
Citação
Paulino, J.CS. Comparação agronómica e económica de tecnologias alternativas na cultura do arroz. Lisboa: ISA-Universidade de Lisboa, 2023. Dissertação de Mestrado
Editora
Instituto Superior de Agronomia, Universidade de Lisboa