Adubação foliar com nitrato de potássio em algodoeiro
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Data
2007-01-01
Autores
Rosolem, Ciro Antonio [UNESP]
Witacker, João Paulo Teixeira
Título da Revista
ISSN da Revista
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Editor
Instituto Agronômico de Campinas
Resumo
Em diversas lavouras de algodão, no Brasil e no exterior, tem ocorrido deficiência tardia de potássio. Com o objetivo de verificar a influência da adubação foliar com nitrato de potássio (KNO3) na nutrição e produção de algodão (Gossypium hirsutum L.), em vista do nível de nutrição potássica, da época de aplicação e dose do produto, em locais com diferentes potenciais de produtividade, foram desenvolvidos experimentos em dois anos agrícolas (2000/2001 e 2001/2002). Foram empregadas doses de 16 e 32 kg ha-1 de KNO3, divididas em duas ou quatro aplicações, a partir da primeira semana de florescimento do algodoeiro. em outro experimento, foi aplicado 32 kg ha-1 de KNO3, em quatro aplicações realizadas da segunda à quinta semana de florescimento. A diminuição dos teores de potássio nas folhas do algodoeiro é um processo normal na fase de senescência da folha em fim de ciclo e não foi revertido com uso suplementar de K. A adubação foliar com KNO3 pode, em algumas condições, como por exemplo, em plantas deficientes em potássio, aumentar o teor do nutriente na folha. Entretanto, isso não afeta o conteúdo do nutriente nos frutos, a produtividade e a qualidade da fibra.
Potassium deficiency developing late in the plant cycle has been observed in some cotton fields in Brazil and abroad. Experiments were conducted during 2 years to study the effects of timing and rates of foliar fertilization with KNO3 on cotton (Gossypium hirsutum L.) nutrition, yields and fiber quality in sites with different yield potentials. The experiments were developed in Pederneiras and Boracéia, SP, in the seasons 2000/2001 and 2001/2002. In the first two experiments 16 or 32 kg ha-1 of KNO3 were split in two or four times starting at the first week of flowering. In the other experiment 32 kg ha-1 of KNO3 were split in four times from the second to the fifth week of flowering. The decrease observed in K contents of cotton leaves was considered a natural process and was not reversed by K application. Foliar fertilization with KNO3 could, in some conditions, as in cotton plants deficient in K, increase the K contents in the leaves. However, this did not affect K contents in the cotton fruits, cotton yields and fiber quality.
Potassium deficiency developing late in the plant cycle has been observed in some cotton fields in Brazil and abroad. Experiments were conducted during 2 years to study the effects of timing and rates of foliar fertilization with KNO3 on cotton (Gossypium hirsutum L.) nutrition, yields and fiber quality in sites with different yield potentials. The experiments were developed in Pederneiras and Boracéia, SP, in the seasons 2000/2001 and 2001/2002. In the first two experiments 16 or 32 kg ha-1 of KNO3 were split in two or four times starting at the first week of flowering. In the other experiment 32 kg ha-1 of KNO3 were split in four times from the second to the fifth week of flowering. The decrease observed in K contents of cotton leaves was considered a natural process and was not reversed by K application. Foliar fertilization with KNO3 could, in some conditions, as in cotton plants deficient in K, increase the K contents in the leaves. However, this did not affect K contents in the cotton fruits, cotton yields and fiber quality.
Descrição
Palavras-chave
Nutrição potássica, Gossypium hirsutum, qualidade da fibra, Fiber quality, Gossypium hirsutum, Potassium nutrition
Como citar
Bragantia. Instituto Agronômico de Campinas, v. 66, n. 1, p. 147-155, 2007.