Utilização da medida do clorofilômetro no manejo da adubação nitrogenada em plantas de pimentão
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Data
2003-12-01
Autores
Godoy, L. J. G. [UNESP]
Villas Boas, Roberto Lyra [UNESP]
Büll, Leonardo Theodoro [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Ciência do Solo
Resumo
O adequado manejo da adubação nitrogenada ao longo do ciclo da cultura do pimentão é complicado pela falta de um índice do N disponível no solo e por ser a análise química de folhas um método de diagnose demorado. Foi realizado um experimento em vasos, em um túnel de plástico pertencente ao Departamento de Recursos Naturais/Ciência do Solo, da FCA/UNESP, Botucatu (SP), com o objetivo de avaliar o índice de suficiência de nitrogênio (ISN), calculado com base nas medidas do clorofilômetro, como ferramenta auxiliar no manejo da adubação nitrogenada em plantas de pimentão. O experimento foi composto de doses de N (4,9; 9,8; 14,7; 19,6; e 24,5 g de N 50 kg-1 de solo - uma planta) aplicadas de modo convencional ou pela fertirrigação e um tratamento em que as plantas não receberam apenas a adubação nitrogenada, com sete repetições. As medidas do clorofilômetro foram realizadas a cada 15 dias em cinco folhas recém-maduras por planta. O ISN foi calculado pela relação entre a média das medidas do clorofilômetro nas plantas dos tratamentos (MCT) e a média das medidas do clorofilômetro nas plantas que receberam a maior dose (MCR), na área de referência (ISN = MCT/MCR x 100). O ISN pode ser um bom indicador do momento de aplicação do adubo nitrogenado e auxiliar no ajuste da dose de N de acordo com a exigência das plantas de pimentão, com a finalidade de aumentar a eficiência de utilização do N aplicado.
An adequate nitrogen fertilizing management throughout a crop cycle of bell pepper (Capsicum annuum L.) is problematical for lack of an index of available soil N and because the chemical leaf analysis, on the other hand, is a slow diagnosis method. The experiment was conducted in a plastic tunnel of the Dept. of Natural Resources/Soil Science, of FCA/UNESP, Botucatu, São Paulo State, in pots, with the objective to assess the nitrogen sufficiency index (NSI). Calculations consisted in chlorophyll meter readings as auxiliary tool in the N fertilization management of bell pepper plants. The experiment, in seven replicates, was composed of five N doses (4.9; 9.8; 14.7; 19.6; and 24.5 g of N 50 kg-1 soil - one plant) applied in conventional manner or through (fertirrigation) and one treatment in which plants were treated with other fertilizers beside N. The chlorophyll meter was read fortnightly in five recently matured leaves per plant. The NSI was calculated by the relationship between the readings average of the chlorophyll meter in the treatments plants (LCT) and the readings average of the chlorophyll meter in the plants that had received the largest dose (LCR), in the reference area (NSI = LCT/LCR x 100). The NSI value can be useful to indicate the moment of N application and to help calibrate N rates according to the bell pepper requirements in order to increase the N-efficiency use.
An adequate nitrogen fertilizing management throughout a crop cycle of bell pepper (Capsicum annuum L.) is problematical for lack of an index of available soil N and because the chemical leaf analysis, on the other hand, is a slow diagnosis method. The experiment was conducted in a plastic tunnel of the Dept. of Natural Resources/Soil Science, of FCA/UNESP, Botucatu, São Paulo State, in pots, with the objective to assess the nitrogen sufficiency index (NSI). Calculations consisted in chlorophyll meter readings as auxiliary tool in the N fertilization management of bell pepper plants. The experiment, in seven replicates, was composed of five N doses (4.9; 9.8; 14.7; 19.6; and 24.5 g of N 50 kg-1 soil - one plant) applied in conventional manner or through (fertirrigation) and one treatment in which plants were treated with other fertilizers beside N. The chlorophyll meter was read fortnightly in five recently matured leaves per plant. The NSI was calculated by the relationship between the readings average of the chlorophyll meter in the treatments plants (LCT) and the readings average of the chlorophyll meter in the plants that had received the largest dose (LCR), in the reference area (NSI = LCT/LCR x 100). The NSI value can be useful to indicate the moment of N application and to help calibrate N rates according to the bell pepper requirements in order to increase the N-efficiency use.
Descrição
Palavras-chave
Capsicum annuum L., SPAD, clorofila, índice de suficiência de nitrogênio, Capsicum annuum L., SPAD, chlorophyll, nitrogen sufficiency index
Como citar
Revista Brasileira de Ciência do Solo. Sociedade Brasileira de Ciência do Solo, v. 27, n. 6, p. 1049-1056, 2003.