Estratégias de alocação de água para irrigação no perímetro irrigado Pontal Sul
Carregando...
Data
2020-03-04
Autores
de Souza, Marcello Henryque Costa [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Diante dos problemas relacionados com a seca no Semiárido, aliada a alterações climáticas e ao aumento populacional, é necessário desenvolver ações de planejamento, estratégias de alocação, manejo e uso adequado da água nos perímetros de irrigação dessa região. Dessa forma, esse trabalho teve como objetivos: i) determinar a demanda hídrica do perímetro irrigado Pontal Sul em duas maneiras, sendo uma semelhante a utilizada no seu projeto básico, e a segunda utilizando o programa MCID (Modelo Computacional para Suporte à Decisão em Irrigação e Drenagem), considerando períodos de maior demanda, elaborados de acordo com a simulação de diferentes cenários agrícolas; ii) gerar cenários baseados nas condições climáticas locais, para culturas perenes já implantadas na região, e na disponibilidade de água oferecida pelo perímetro irrigado, para definir quais culturas e em que proporções de ocupação da área poderão ser atendidas, com base na capacidade de bombeamento e condução de água do perímetro irrigado; iii) identificar onde, quando e em qual cenário há maior necessidade hídrica. Foram realizados levantamentos de dados, estudos bibliográficos, geração de cenários agrícolas e determinação das demandas na área do perímetro irrigado, para avaliar as condições de fornecimento de água aos lotes irrigados. De acordo com os cenários gerados, constatou-se que o perímetro irrigado Pontal Sul apresenta dados que favorecem a superestimação dos valores de água a serem fornecidos, visando garantir a demanda exigida pelas culturas; entretanto, tal fato não foi suficiente para evitar problemas futuros, quando avaliados os cenários, as condições climáticas desfavoráveis ou de exigência máxima das culturas. Essa constatação foi obtida a partir dos diferentes métodos de estimativa avaliados, demonstrando que em determinadas situações, o sistema de canais do projeto não atenderá a demanda dos cenários avaliados, tanto nos cálculos estimados pelo projeto, como pelo MCID. Portanto, é extremamente necessário o estudo prévio, o planejamento adequado para implantação das culturas e o uso de sistemas de irrigação, diante da inexistência de planejamento para muitos produtores. Dessa forma, o uso dessa metodologia para o planejamento da propriedade agrícola e do perímetro irrigado, pode servir de base para a definição das culturas a serem implantadas, das melhores épocas para poda (clima mais propício). Ademais, a utilização de um sistema de irrigação adequado proporcionará a quantidade de água necessária ao pleno desenvolvimento da cultura e o fornecimento ininterrupto ao longo do seu ciclo.
In view of the problems related to drought in the Brazilian semiarid region, together the climate change and population growth, it is necessary to develop planning actions, allocation strategies, management and adequate use of water in the irrigation schemes of that region. Thus, this work had as objectives: i) to determine the water demand of the Pontal Sul irrigation scheme in two ways, one similar to that used in its basic project, and the second using the program MCID (Computational Model to Support Decision in Irrigation and Drainage), considering periods of greater water demand according to the simulation of different agricultural scenarios; ii) to generate scenarios based on local weather conditions for perennial crops already used in that region, and on the water availability offered by the irrigation scheme, to define which crops and in what area proportions, based on the water pumping capacity and delivery from the irrigation scheme; iii) to identify where, when and in which scenario there is a greater water demand. Data surveys, bibliographic reviews, generation of agricultural scenarios and determination of demands in the area of the irrigation scheme were carried out to assess the conditions of water supply to the irrigated grower´s areas. According to the generated scenarios, it was found that the irrigation scheme presents conditions that favor the overestimation of the water values to be supplied, aiming to guarantee the crop water demands; however, this fact was not enough to avoid future problems, when evaluating the scenarios, the unfavorable weather conditions or the maximum crop water demands. This finding was obtained from the different estimation methods evaluated, demonstrating that in certain conditions the channel system will not meet the demand of the evaluated scenarios, either in the calculations estimated by the project or by the MCID. Therefore, a previous study is necessary to adequate planning for selection of crops and the use of irrigation systems, given the lack of planning for many growers. Thus, the use of this methodology for the planning of the grower´s area and the irrigation scheme can be useful as a basis for the selection of crops and best times for pruning (based on weather conditions). In addition, the use of an adequate irrigation system will provide the amount of water needed for the full crop development, and an uninterrupted supply throughout the growing season.
In view of the problems related to drought in the Brazilian semiarid region, together the climate change and population growth, it is necessary to develop planning actions, allocation strategies, management and adequate use of water in the irrigation schemes of that region. Thus, this work had as objectives: i) to determine the water demand of the Pontal Sul irrigation scheme in two ways, one similar to that used in its basic project, and the second using the program MCID (Computational Model to Support Decision in Irrigation and Drainage), considering periods of greater water demand according to the simulation of different agricultural scenarios; ii) to generate scenarios based on local weather conditions for perennial crops already used in that region, and on the water availability offered by the irrigation scheme, to define which crops and in what area proportions, based on the water pumping capacity and delivery from the irrigation scheme; iii) to identify where, when and in which scenario there is a greater water demand. Data surveys, bibliographic reviews, generation of agricultural scenarios and determination of demands in the area of the irrigation scheme were carried out to assess the conditions of water supply to the irrigated grower´s areas. According to the generated scenarios, it was found that the irrigation scheme presents conditions that favor the overestimation of the water values to be supplied, aiming to guarantee the crop water demands; however, this fact was not enough to avoid future problems, when evaluating the scenarios, the unfavorable weather conditions or the maximum crop water demands. This finding was obtained from the different estimation methods evaluated, demonstrating that in certain conditions the channel system will not meet the demand of the evaluated scenarios, either in the calculations estimated by the project or by the MCID. Therefore, a previous study is necessary to adequate planning for selection of crops and the use of irrigation systems, given the lack of planning for many growers. Thus, the use of this methodology for the planning of the grower´s area and the irrigation scheme can be useful as a basis for the selection of crops and best times for pruning (based on weather conditions). In addition, the use of an adequate irrigation system will provide the amount of water needed for the full crop development, and an uninterrupted supply throughout the growing season.
Descrição
Palavras-chave
Planejamento agrícola, Semiárido, Modelagem, Agricultural planning, Modelling, Semiarid