Formulações encapsuladas de clomazone como estratégia para melhorar a dinâmica na palha, a disponibilidade no solo e a seletividade na soja em pós-emergência
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Data
2024-02-21
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Universidade Estadual Paulista (Unesp)
Resumo
Para alcançar a máxima eficiência no controle químico de plantas daninhas, é imprescindível investir no desenvolvimento de formulações otimizadas e adequadas para o sistema de cultivo, assim como conhecer as características físico-químicas da molécula e os processos envolvidos na sua dinâmica ambiental. Desse modo, o presente trabalho foi realizado com o intuito de determinar a dinâmica de formulações do herbicida clomazone no solo, em palha de milho e em plantas de soja, com aplicação em pós-emergência da cultura. Em todos os estudos foram realizadas aplicações de quatro formulações de clomazone, sendo elas: Kaivana® CS, Reator® CS, Gamit Star® EC e GrandeBR EC, na dose de 720 g i.a. ha-1. Os experimentos de dinâmica no solo e em palha foram implantados em delineamento inteiramente ao acaso, com quatro repetições. Para o estudo em solo, foi utilizado um solo com textura média acondicionado em um recipiente plástico e em sua superfície os produtos foram aplicados com o auxílio de uma micropipeta de repetição. Em seguida, as amostras tratadas foram homogeneizadas e transferidas para cápsulas de polipropileno que, posteriormente, foram submetidas à simulação de chuvas aos 1, 3, 7, 14 e 30 dias após a aplicação (DAA). No segundo estudo, os produtos foram aplicados em cápsulas preenchidas com palha de milho, equivalente a 6 t ha-1, submetidas à simulação de diferentes lâminas de chuva (10, 20, 35, 50 e 100 mm), 1 DAA. As soluções lixiviadas do solo e da palha foram coletadas e armazenadas para determinação dos teores de clomazone por cromatografia e espectrometria de massas. O estudo em plantas de soja foi implantado em delineamento inteiramente ao acaso, com oito repetições. Os tratamentos consistiram na aplicação das quatro formulações de clomazone em plantas de soja, submetidas à simulação de 20 mm de chuva aos 1, 3 e 7 DAA, sendo adicionado um tratamento sem chuva simulada. Foram determinados os teores de massa seca das plantas (20 DAA) e realizada a coleta das unidades experimentais (1, 3 e 7 DAA) para a quantificação dos teores de clomazone e seus metabólitos que se apresentaram interna e externamente às folhas de soja, ambos realizados por cromatografia e espectrometria de massas. Os produtos microencapsulados, Kaivana e Reator, apresentaram liberação lenta e prolongada da molécula no solo, o que pode resultar em um aumento do seu efeito residual, devido ao rompimento gradativo das cápsulas ao longo do tempo. O microencapsulamento do clomazone influenciou a dinâmica inicial do herbicida, uma vez que a maior fração da molécula estava preservada na matriz polimérica da formulação, ficando menos sujeita aos processos de perdas e proporcionando maior saída do produto da palha de milho, após uma chuva e/ou irrigação. Quando aplicada em pós-emergência da cultura da soja, a formulação microencapsulada se mostrou mais segura com relação à formulação convencional (concentrado emulsionável), fato este relacionado aos menores teores internos encontrados nas plantas e, consequentemente, menores reduções nos teores de massa seca.
To achieve maximum efficiency in the chemical control of weeds, it is essential to invest in the development of optimized formulations suitable for the cultivation system, as well as knowing the physicochemical characteristics of the molecule and the processes involved in its environmental dynamics. Therefore, the present work was carried out with the aim of determining the dynamics of formulations of the herbicide clomazone in the soil, in corn crop residue and in soybean plants, with application in post-emergence of the crop. In all studies, four formulations of clomazone were applied, namely: Kaivana® CS, Reator® CS, Gamit Star® EC and GrandeBR EC, were used at a rate of 720 g a.i. ha-1. Soil and straw dynamics experiments were implemented in a completely randomized design, with four replications. For the soil study, a medium textured soil was used, packed in a plastic container and the products were applied to its surface with the aid of a repeating micropipette. Then, the treated samples were homogenized and transferred to polypropylene capsules, which were subsequently subjected to rainfall simulation at 1, 3, 7, 14 and 30 days after application (DAA). In the second study, the products were applied in capsules filled with corn straw, equivalent to 6 t ha-1, subjected to simulation of different rainfall volumes (10, 20, 35, 50 and 100 mm), 1 DAA. Leached soil and straw solutions were collected and stored to determine clomazone levels by chromatography and mass spectrometry. The study on soybean plants was implemented in a completely randomized design, with eight replications. The treatments consisted of applying the four clomazone formulations to soybean plants, subjected to simulated 20 mm of rainfall at 1, 3 and 7 DAA, with the addition of a treatment without simulated rainfall. Dry mass levels of the plants were determined (20 DAA) and the experimental units were collected (1, 3 and 7 DAA) to quantify the levels of clomazone and its metabolites that were present internally and externally to soybean leaves, both carried out by chromatography and mass spectrometry. The microencapsulated products, Kaivana and Reator, exhibited a slow and prolonged release of the molecule into the soil, which could result in an increase in its residual effect, due to the gradual rupture of the capsules over time. Microencapsulation of clomazone influenced the initial dynamics of the herbicide, since the largest fraction of the molecule was preserved in the polymeric matrix of the formulation, being less subject to loss processes and providing greater output of the product from the corn straw, after rain and/ or irrigation. When applied post-emergence of soybean crops, the microencapsulated formulation proved to be safer compared to the conventional formulation (emulsifiable concentrate), a fact related to the lower internal levels found in the plants and, consequently, smaller reductions in dry mass levels.
To achieve maximum efficiency in the chemical control of weeds, it is essential to invest in the development of optimized formulations suitable for the cultivation system, as well as knowing the physicochemical characteristics of the molecule and the processes involved in its environmental dynamics. Therefore, the present work was carried out with the aim of determining the dynamics of formulations of the herbicide clomazone in the soil, in corn crop residue and in soybean plants, with application in post-emergence of the crop. In all studies, four formulations of clomazone were applied, namely: Kaivana® CS, Reator® CS, Gamit Star® EC and GrandeBR EC, were used at a rate of 720 g a.i. ha-1. Soil and straw dynamics experiments were implemented in a completely randomized design, with four replications. For the soil study, a medium textured soil was used, packed in a plastic container and the products were applied to its surface with the aid of a repeating micropipette. Then, the treated samples were homogenized and transferred to polypropylene capsules, which were subsequently subjected to rainfall simulation at 1, 3, 7, 14 and 30 days after application (DAA). In the second study, the products were applied in capsules filled with corn straw, equivalent to 6 t ha-1, subjected to simulation of different rainfall volumes (10, 20, 35, 50 and 100 mm), 1 DAA. Leached soil and straw solutions were collected and stored to determine clomazone levels by chromatography and mass spectrometry. The study on soybean plants was implemented in a completely randomized design, with eight replications. The treatments consisted of applying the four clomazone formulations to soybean plants, subjected to simulated 20 mm of rainfall at 1, 3 and 7 DAA, with the addition of a treatment without simulated rainfall. Dry mass levels of the plants were determined (20 DAA) and the experimental units were collected (1, 3 and 7 DAA) to quantify the levels of clomazone and its metabolites that were present internally and externally to soybean leaves, both carried out by chromatography and mass spectrometry. The microencapsulated products, Kaivana and Reator, exhibited a slow and prolonged release of the molecule into the soil, which could result in an increase in its residual effect, due to the gradual rupture of the capsules over time. Microencapsulation of clomazone influenced the initial dynamics of the herbicide, since the largest fraction of the molecule was preserved in the polymeric matrix of the formulation, being less subject to loss processes and providing greater output of the product from the corn straw, after rain and/ or irrigation. When applied post-emergence of soybean crops, the microencapsulated formulation proved to be safer compared to the conventional formulation (emulsifiable concentrate), a fact related to the lower internal levels found in the plants and, consequently, smaller reductions in dry mass levels.
Descrição
Palavras-chave
Formulação microencapsulada, Absorção, Seletividade, Lixiviação, Cromatografia, Microencapsulated formulation, Absorption, Selectivity, Leaching, Chromatography
Como citar
BONAMICHI, J. A. Formulações encapsuladas de clomazone como estratégia para melhorar a dinâmica na palha, a disponibilidade no solo e a seletividade na soja em pós-emergência. 2024. Dissertação (Agricultura) – Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, Botucatu, 2024.