Fertilização do solo na severidade da ferrugem asiática da soja
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Data
2017-07-15
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Universidade Federal de Viçosa
Resumo
A ferrugem asiática causada pelo fungo Phakopsora pachyrizi, é uma das principais doenças da soja. Em condições favoráveis, a doença pode ser um fator limitante para a produção. Atualmente, o controle da doença é realizado por meio da aplicação de fungicidas, vazio sanitário, plantio de cultivares precoces e adubação equilibrada. Dessa forma, o objetivo deste trabalho foi avaliar o efeito do incremento da adubação fosfatada, potássica e nitrogenada sobre a ferrugem asiática da soja. Foram conduzidos 2 experimentos em condições de campo, com delineamento de blocos ao acaso, com 6 doses de N, P e K (0, 25, 50, 100, 200 e 400 mg/dm3) e 2 experimentos em vasos sobre condições de campo, sendo um deles com 6 doses de N, P e K (0, 50, 100, 200, 400 e 800 mg/dm3), e o outro com 4 doses de P e K (0, 100, 200 e 400 mg/dm3) e 4 doses de N (0, 50, 100 e 200 mg/dm3). A aplicação de fungicida (Azoxistrobina + Ciproconazol) foi realizada aos 45, 60 e 75 dias após a emergência (DAE) nos tratamentos com controle químico. Foram avaliados severidade, porcentagem de controle, área abaixo da curva de progresso da doença (AACPD), taxa de progresso da doença (r), produtividade e teor de clorofila a e b. A severidade, a AACPD e a taxa de progresso da doença reduziram conforme o incremento na adubação fosfatada e potássica e a aplicação de fungicida, enquanto a porcentagem de controle e a produtividade aumentaram. Os teores de clorofila a e b também apresentaram maiores valores conforme o incremento na dose de P e K. No experimento de N, o incremento da adubação nitrogenada aumentou a severidade, a AACPD, a taxa de progresso da doença, os teores de clorofila a e b, e a produtividade. Com bases nos dados obtidos, concluiu-se que a adubação equilibrada com fósforo e potássio e a aplicação de fungicida são estratégias que podem ser implementadas no manejo integrado, possibilitando maior eficiência no controle da ferrugem asiática da soja, enquanto o nitrogênio apesar de aumentar produtividade, aumenta a severidade da ferrugem da soja.
The Asian rust caused by the fungus Phakopsora pachyrizi, is one of the major diseases of soybean. Under favorable conditions, disease can be a limiting factor for production. Currently, the control of the disease is carried out through the application of fungicides, sanitary void, planting of early cultivars and balanced fertilization. Thus, the objective of this work is to evaluate the effect of phosphate, potassium and nitrogen fertilization on an asian soybean rust. Two trials were received in field conditions, with a randomized block design, with 6 doses of N, P and K (0, 25, 50, 100, 200 and 400 mg / dm3) and 2 potting experiments on field conditions (0, 100, 200, 400 and 800 mg / dm3), the other with 4 doses of P and K (0, 100, 200 and 400 mg / dm3) and 4 doses of N (0, 50, 100 and 200 mg / dm3). The application of fungicide (Azoxystrobin + Ciproconazole) was performed at 45, 60 and 75 days after emergence (DAE) in the treatments with chemical control. The severity, percentage of control, area below the disease progress curve (AACPD), rate of disease progression (r), productivity and chlorophyll content a and b were evaluated. The severity, AACPD and rate of progress of the disease reduced as the increase in phosphate and potassium fertilization and a fungicide application, while a percentage of control and a production increased. Nitrogen testing, nitrogen fertilization increased severity, AACPD, rates of disease progression, chlorophyll content and yield, and yield. Based on the data obtained, it was concluded that it is a balanced fertilization with phosphorus and potassium and application of fungicide are structures that can be implemented without integrated management, allowing greater efficiency in the control of soybean asian rust, while nitrogen, despite increasing the productivity, increase the severity of soybean rust.
The Asian rust caused by the fungus Phakopsora pachyrizi, is one of the major diseases of soybean. Under favorable conditions, disease can be a limiting factor for production. Currently, the control of the disease is carried out through the application of fungicides, sanitary void, planting of early cultivars and balanced fertilization. Thus, the objective of this work is to evaluate the effect of phosphate, potassium and nitrogen fertilization on an asian soybean rust. Two trials were received in field conditions, with a randomized block design, with 6 doses of N, P and K (0, 25, 50, 100, 200 and 400 mg / dm3) and 2 potting experiments on field conditions (0, 100, 200, 400 and 800 mg / dm3), the other with 4 doses of P and K (0, 100, 200 and 400 mg / dm3) and 4 doses of N (0, 50, 100 and 200 mg / dm3). The application of fungicide (Azoxystrobin + Ciproconazole) was performed at 45, 60 and 75 days after emergence (DAE) in the treatments with chemical control. The severity, percentage of control, area below the disease progress curve (AACPD), rate of disease progression (r), productivity and chlorophyll content a and b were evaluated. The severity, AACPD and rate of progress of the disease reduced as the increase in phosphate and potassium fertilization and a fungicide application, while a percentage of control and a production increased. Nitrogen testing, nitrogen fertilization increased severity, AACPD, rates of disease progression, chlorophyll content and yield, and yield. Based on the data obtained, it was concluded that it is a balanced fertilization with phosphorus and potassium and application of fungicide are structures that can be implemented without integrated management, allowing greater efficiency in the control of soybean asian rust, while nitrogen, despite increasing the productivity, increase the severity of soybean rust.
Descrição
Palavras-chave
Soja - Doenças e pragas, Ferrugem asiática, Ferrugem de soja (Doença), Phakopsora pachyrhizi, Glycine max, Plantas - Nutrição
Citação
MOCHKO, Ana Claudia Ruschel. Fertilização do solo na severidade da ferrugem asiática da soja. 2017. 75 f. Dissertação (Mestrado em Fitopatologia) - Universidade Federal de Viçosa, Viçosa. 2017.