Formas de aplicação de silício e o seu efeito na mitigação da toxidez de zinco no milho
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Data
2021-08-31
Autores
Silva, Ana Paula Rodrigues da
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Universidade Estadual Paulista (Unesp)
Resumo
A contaminação do solo em áreas agrícolas vem sendo motivo de preocupação nas últimas décadas. Esta é causada pelo uso inadequado e descarte de resíduos industriais, fertilizantes, agroquímicos que contém elementos tóxicos em sua composição. Embora o zinco seja um micronutriente para as plantas o seu excesso pode ocasionar danos nas raízes e por consequência redução da biomassa, transporte e a absorção de água e nutrientes. O silício é um elemento benéfico conhecido por reduzir estresses bióticos e abióticos em plantas. O objetivo deste trabalho foi verificar a eficiência de diferentes formas de aplicação de silício e o seu efeito na mitigação de níveis intermediário e alto de zinco em dois tipos de solo na cultura do milho. Foram conduzidos dois experimentos em túnel de plástico, em ambos o delineamento experimental utilizado foi em blocos casualizados, em esquema fatorial 3 x 9, com quatro repetições. Os tratamentos dos experimentos foram constituídos de três formas de aplicação de silício (via sulco, via foliar e em área total) e doses combinadas e individuais de silício e de zinco em nível intermediário e tóxico [1:controle (sem aplicação de silício e zinco); 2: Si1 (aplicação de 30 mg kg-1de Si); 3: Si2 (aplicação de 120 mg kg-1de Si); 4: Zn1 (aplicação de 20 mg kg-1 de Zn); 5: Zn2 (aplicação de 60 mg kg-1 de Zn); 6: Si1+Zn1 (aplicação de 30 mg kg-1 de Si e 20 mg kg-1 de Zn); 7: Si1+Zn2 (aplicação de 30 mg kg-1 de Si e 60 mg kg-1 de Zn); 8: Si2+Zn1( aplicação de 120 mg kg-1 de Si e 20 mg kg-1de Zn) e 9: Si2+Zn2 (aplicação de 120 mg kg-1 de Si e 60 mg kg-1 de Zn) exceto quando o silício foi aplicado via foliar, no qual foi fornecido uma concentração de 2,56 e 7,68 mg de Si vaso-1 para os tratamentos Si1 e Si2, respectivamente]. No experimento I as plantas de milho foram cultivadas em solo arenoso, enquanto no experimento II em solo argiloso. Em ambos os experimentos, as avaliações foram realizadas aos 30 dias de ciclo, tanto na planta [altura da planta, número de folhas, índice relativo de clorofila (IRC), estimativa de área foliar, massa seca das folhas, colmo, raiz e parte aérea, teor e acúmulo de macronutrientes, micronutrientes e silício na parte aérea (N, P, K, Ca, Mg, S, B, Cu, Fe, Mg, Zn e Si)], quanto no solo (pH, V%, H+Al, P, K, Ca, Mg, S, B, Cu, Mn, Zn e Si). Conclui-se que independentemente do tipo de solo, nem sempre o Si se comportou como mitigador dos teores de Zn no solo e na planta e as formas de aplicação influenciaram na mitigação de Zn apenas no teor de Zn do solo argiloso. As formas de aplicação de Si no solo arenoso influenciaram na massa seca da parte aérea, raiz e caule, acúmulo de N, S, B, e Cu e teor de N, Cu e Mg na parte das plantas e para o teor de K e V% no solo. Enquanto no solo argiloso, as formas de aplicação de Si influenciaram no teor de K e Mn da parte aérea das plantas de milho e teor de S no solo.
Soil contamination in agricultural areas has been a matter of concern in recent decades. This is caused by the inappropriate use and disposal of industrial waste, fertilizers, agrochemicals that contain toxic elements in their composition. Although zinc is a micronutrient for plants, its excess can damage the roots and consequently reduce biomass, transport, and absorb water and nutrients. Silicon is a beneficial element known to reduce biotic and abiotic stresses in plants. The objective of this work was to verify the efficiency of different forms of silicon application and its effect on the mitigation of intermediate and high levels of zinc in two types of soil in the corn crop. Two experiments were carried out in a plastic tunnel, in both the experimental design used was a randomized block design, in a 3 x 9 factorial scheme, with four replications. The treatments of the experiments consisted of three forms of silicon application (via furrow, foliar and total area) and combined and individual doses of silicon and zinc at intermediate and toxic levels [1: control (without silicon and zinc application ); 2: Si1 (application of 30 mg kg-1 of Si); 3: Si2 (application of 120 mg kg 1 of Si); 4: Zn1 (20 mg kg-1 Zn application); 5: Zn2 (application of 60 mg kg-1 of Zn); 6: Si1+Zn1 (application of 30 mg kg-1 of Si and 20 mg kg-1 of Zn); 7: Si1+Zn2 (application of 30 mg kg-1 of Si and 60 mg kg-1 of Zn); 8: Si2+Zn1 (application of 120 mg kg-1 of Si and 20 mg kg-1 of Zn) and 9: Si2+Zn2 (application of 120 mg kg-1 of Si and 60 mg kg-1 of Zn) except when silicon was applied via foliar, in which a concentration of 2.56 and 7.68 mg of Si pot-1 was provided for treatments Si1 and Si2, respectively]. In experiment I corn plants were grown in sandy soil, while in experiment II in clayey soil. In both experiments, evaluations were carried out at 30 days of cycle, both on the plant [plant height, number of leaves, relative chlorophyll index (RCI), leaf area estimate, dry mass of leaves, stalk, root and part aerial, content and accumulation of macronutrients, micronutrients and silicon in the aerial part (N, P, K, Ca, Mg, S, B, Cu, Fe, Mg, Zn and Si)], and in the soil (pH, V %, H+Al, P, K, Ca, Mg, S, B, Cu, Mn, Zn and Si). It was concluded that, regardless of the type of soil, Si did not always act as a mitigator of the Zn content in the soil and in the plant, and the application forms influenced the Zn mitigation only in the Zn content of the clayey soil. The forms of Si application in the sandy soil influenced in the dry mass of shoots, root and stem, accumulation of N, S, B, and Cu and N, Cu and Mg content in the plant part and for the K and V% content in the soil. While in clay soil, the application forms of Si influenced the K and Mn content of the aerial part of the corn plants and S content in the soil.
Soil contamination in agricultural areas has been a matter of concern in recent decades. This is caused by the inappropriate use and disposal of industrial waste, fertilizers, agrochemicals that contain toxic elements in their composition. Although zinc is a micronutrient for plants, its excess can damage the roots and consequently reduce biomass, transport, and absorb water and nutrients. Silicon is a beneficial element known to reduce biotic and abiotic stresses in plants. The objective of this work was to verify the efficiency of different forms of silicon application and its effect on the mitigation of intermediate and high levels of zinc in two types of soil in the corn crop. Two experiments were carried out in a plastic tunnel, in both the experimental design used was a randomized block design, in a 3 x 9 factorial scheme, with four replications. The treatments of the experiments consisted of three forms of silicon application (via furrow, foliar and total area) and combined and individual doses of silicon and zinc at intermediate and toxic levels [1: control (without silicon and zinc application ); 2: Si1 (application of 30 mg kg-1 of Si); 3: Si2 (application of 120 mg kg 1 of Si); 4: Zn1 (20 mg kg-1 Zn application); 5: Zn2 (application of 60 mg kg-1 of Zn); 6: Si1+Zn1 (application of 30 mg kg-1 of Si and 20 mg kg-1 of Zn); 7: Si1+Zn2 (application of 30 mg kg-1 of Si and 60 mg kg-1 of Zn); 8: Si2+Zn1 (application of 120 mg kg-1 of Si and 20 mg kg-1 of Zn) and 9: Si2+Zn2 (application of 120 mg kg-1 of Si and 60 mg kg-1 of Zn) except when silicon was applied via foliar, in which a concentration of 2.56 and 7.68 mg of Si pot-1 was provided for treatments Si1 and Si2, respectively]. In experiment I corn plants were grown in sandy soil, while in experiment II in clayey soil. In both experiments, evaluations were carried out at 30 days of cycle, both on the plant [plant height, number of leaves, relative chlorophyll index (RCI), leaf area estimate, dry mass of leaves, stalk, root and part aerial, content and accumulation of macronutrients, micronutrients and silicon in the aerial part (N, P, K, Ca, Mg, S, B, Cu, Fe, Mg, Zn and Si)], and in the soil (pH, V %, H+Al, P, K, Ca, Mg, S, B, Cu, Mn, Zn and Si). It was concluded that, regardless of the type of soil, Si did not always act as a mitigator of the Zn content in the soil and in the plant, and the application forms influenced the Zn mitigation only in the Zn content of the clayey soil. The forms of Si application in the sandy soil influenced in the dry mass of shoots, root and stem, accumulation of N, S, B, and Cu and N, Cu and Mg content in the plant part and for the K and V% content in the soil. While in clay soil, the application forms of Si influenced the K and Mn content of the aerial part of the corn plants and S content in the soil.
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Palavras-chave
Silicato, Remediação, Elementos-traço, Elemento benéfico, Beneficial element, Silicate, Trace elements, Remediation