Uso de laser de CO2 no controle de plantas daninhas
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Data
2022-07-01
Autores
Pavan, Guilherme Bacarim [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Ao longo de toda a história humana, métodos químicos, físicos ou mecânicos de controle de plantas daninhas sempre foram utilizados. Dispositivos que se aproveitam de meios mecânicos e térmicos para o controle de plantas daninhas têm se tornado cada vez mais adotados. O método de controle de plantas daninhas pelo do uso de laser ainda é pouco conhecido, havendo poucos estudos publicados. Esse trabalho teve o objetivo de avaliar qual o melhor método de aplicação para experimentos de dose-resposta com laser, por cabeçote ou direta, e avaliar a relação dose-resposta para aplicação de laser em plantas daninhas. Os experimentos foram divididos em duas etapas, a primeira para comparação de métodos de aplicação, por cabeçote ou direta. Na segunda foram feitos experimentos de dose-resposta com diferentes espécies e estádios. Estes foram elaborados no delineamento inteiramente casualizado, com nove tratamentos e quatro repetições, sendo oito doses mais a testemunha. Um conjunto de trinta e seis plantas recebeu as doses através da aplicação direta e o outro pelo cabeçote. As aplicações foram feitas em plantas de Bidens pilosa no estádio de dois pares de folhas completamente expandidas (E2). As aplicações foram realizadas com alvo na parte inferior do caule, a 0,5 cm de distância do solo. As doses aplicadas foram: 0,33, 0,66, 1,33, 2,65, 5,31, 10,61, 21,22 e 42,44 J.mm-2. Aos 7 DAA foi medida a massa de matéria fresca da parte aérea das plantas. Estes dados foram transformados em porcentagem de controle em relação a testemunha e submetidos ao modelo de Mitscherlich. Na segunda etapa sete espécies (Amaranthus viridis, Bidens pilosa, Cenchrus echinatus, Digitaria horizontalis, Eleusine indica, Panicum maximum e Urochloa decumbens) foram submetidas a experimentos de dose-resposta pelo método de aplicação direta, nos estádios E1, E2 e E3. Um conjunto de testemunhas (4 parcelas experimentais) por experimento foi utilizado para análises de massa de matéria fresca, massa de matéria seca e área foliar, AFEMF, AFEMS, teor de umidade e EC80. Esses dados, de todas as espécies e estádios, foram agrupados para realização da análise de correlação de Pearson. Para os tratamentos submetidos a aplicação de laser, foi medida a massa de matéria seca 14 DAA. Os dados foram transformados em porcentagem de controle em relação a testemunha e submetidos ao modelo de Mitscherlich. Concluiu-se que a aplicação da mesma dose de laser de forma direta proporciona um controle mais eficaz de plantas de Bidens pilosa do que por cabeçote. O sistema de aplicação direta é o indicado para realização de experimentos de dose-resposta. As espécies Amaranthus viridis, Bidens pilosa, Cenchrus echinatus, Digitaria horizontalis, Eleusine indica, Panicum maximum e Urochloa decumbens podem ser controladas com o uso de laser de CO2, em E1, E2 e E3. Existe correlação positiva entre a dose estimada para o controle de plantas daninhas por laser e a massa de matéria fresca, massa de matéria seca e área foliar.
Throughout human history, chemical, physical or mechanical methods of weed control have always been used. Devices that take advantage of mechanical and thermal means for weed control have become increasingly adopted. The method of weed control by laser use is still little known, with few studies published. The objective of this work was to evaluate the best application method for dose-response experiments with laser, using a scanner head or direct, and to evaluate the dose-response ratio for laser application in weeds. The experiments were divided into two stages, the first for comparison of application methods, by scanner head or direct. In the second, dose-response experiments were carried out with different species and stages. These were elaborated in a completely randomized design, with nine treatments and four replicates, eight doses plus the control. A set of thirty-six plants received the doses through direct application and the other by the scanner head. The applications were made in Bidens pilosa plants in the stage of two pairs of completely expanded leaves (E2). The applications were performed with a target at the bottom of the stem, 0.5 cm away from the ground. The doses applied were: 0.33, 0.66, 1.33, 2.65, 5.31, 10.61, 21.22 and 42.44 J.mm-2. At 7 DAA, the fresh matter mass of the aerial part of the plants was measured. These data were transformed into a control percentage in relation to the control treatment and submitted to the Mitscherlich model. In the second stage, seven species (Amaranthus viridis, Bidens pilosa, Cenchrus echinatus, Digitaria horizontalis, Eleusine indica, Panicum maximum and Urochloa decumbens) were submitted to dose-response experiments by the direct application method at stages E1, E2 and E3. A set of controls (4 experimental plots) per experiment was used for analysis of fresh matter mass, dry matter mass and leaf area, AFEMF, AFEMS, moisture content and EC80. These data, from all species and stages, were grouped to perform Pearson's correlation analysis. For the treatments submitted to laser application, the dry matter mass 14 DAA was measured. The data were transformed into a control percentage in relation to the control treatment and submitted to the Mitscherlich model. It was concluded that the application of the same laser dose directly provides a more effective control of Bidens pilosa plants than using the scanner head. The direct application system is indicated for dose-response experiments. The species Amaranthus viridis, Bidens pilosa, Cenchrus echinatus, Digitaria horizontalis, Eleusine indica, Panicum maximum and Urochloa decumbens can be controlled with the use of CO2 laser, in E1, E2 and E3. There is a positive correlation between the estimated dose for laser weed control and fresh matter mass, dry matter mass and leaf area.
Throughout human history, chemical, physical or mechanical methods of weed control have always been used. Devices that take advantage of mechanical and thermal means for weed control have become increasingly adopted. The method of weed control by laser use is still little known, with few studies published. The objective of this work was to evaluate the best application method for dose-response experiments with laser, using a scanner head or direct, and to evaluate the dose-response ratio for laser application in weeds. The experiments were divided into two stages, the first for comparison of application methods, by scanner head or direct. In the second, dose-response experiments were carried out with different species and stages. These were elaborated in a completely randomized design, with nine treatments and four replicates, eight doses plus the control. A set of thirty-six plants received the doses through direct application and the other by the scanner head. The applications were made in Bidens pilosa plants in the stage of two pairs of completely expanded leaves (E2). The applications were performed with a target at the bottom of the stem, 0.5 cm away from the ground. The doses applied were: 0.33, 0.66, 1.33, 2.65, 5.31, 10.61, 21.22 and 42.44 J.mm-2. At 7 DAA, the fresh matter mass of the aerial part of the plants was measured. These data were transformed into a control percentage in relation to the control treatment and submitted to the Mitscherlich model. In the second stage, seven species (Amaranthus viridis, Bidens pilosa, Cenchrus echinatus, Digitaria horizontalis, Eleusine indica, Panicum maximum and Urochloa decumbens) were submitted to dose-response experiments by the direct application method at stages E1, E2 and E3. A set of controls (4 experimental plots) per experiment was used for analysis of fresh matter mass, dry matter mass and leaf area, AFEMF, AFEMS, moisture content and EC80. These data, from all species and stages, were grouped to perform Pearson's correlation analysis. For the treatments submitted to laser application, the dry matter mass 14 DAA was measured. The data were transformed into a control percentage in relation to the control treatment and submitted to the Mitscherlich model. It was concluded that the application of the same laser dose directly provides a more effective control of Bidens pilosa plants than using the scanner head. The direct application system is indicated for dose-response experiments. The species Amaranthus viridis, Bidens pilosa, Cenchrus echinatus, Digitaria horizontalis, Eleusine indica, Panicum maximum and Urochloa decumbens can be controlled with the use of CO2 laser, in E1, E2 and E3. There is a positive correlation between the estimated dose for laser weed control and fresh matter mass, dry matter mass and leaf area.
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Palavras-chave
Agricultura, Lasers de dióxido de carbono, Ervas daninhas, Agriculture, Carbon dioxide lasers, Weeds