Exigência de nitrogênio e manejo da adubação nitrogenada em cultivares de feijão-comum de ciclo precoce
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Data
2019-08-12
Autores
Guidorizzi, Fernando Vieira Costa
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Universidade Estadual Paulista (Unesp)
Resumo
Conhecimentos sobre a extração e exportação de nutrientes são importantes para definição do manejo da adubação nas culturas agrícolas. O objetivo desse trabalho foi estudar o acúmulo de matéria seca (MS) e o acúmulo de nitrogênio (N) durante ciclo, a produtividade de grãos e a exportação de N por cultivares de feijão-comum de ciclo normal e precoce, bem como as repostas das cultivares de feijão-comum de ciclo precoce aos manejos da adubação nitrogenada de cobertura. Foram conduzidos dois experimentos no município de Botucatu - SP, nos anos de 2016 e 2017, em solo classificado como Nitossolo Vermelho distrófico. No experimento I, foi adotado o delineamento em blocos casualizados no esquema de parcelas subdivididas, com quatro repetições. As parcelas foram compostas por cultivares de feijão-comum [Pérola (ciclo normal), IAC Imperador, IPR Andorinha e IPR Curió (ciclo precoce)] e as subparcelas por sete de amostragens realizadas durante o ciclo da cultura [14, 28, 42, 56, 70, 77 e 84 DAE (dias após a emergência)]. No experimento II, foi adotado o delineamento em blocos casualizados, com quatro repetições. Os tratamentos foram constituídos a partir da combinação fatorial 3x7, sendo três cultivares de feijão-comum de ciclo precoce (IAC Imperador, IPR Andorinha e IPR Curió) e sete manejos da adubação nitrogenada de cobertura [M1: testemunha - sem aplicação de N em cobertura; M2: 90 kg ha-1 de N em V3; M3: 90 kg ha-1 de N em V4; M4: 45 kg ha-1 de N em V3 + 45 kg ha-1 de N em R5; M5: tratamento referência para as leituras com clorofilômetro, com 90 kg ha-1 de N em V3 + 90 kg ha-1 de N em R5; M6: tratamento que recebeu aplicação de N (30 kg ha-1) somente quando as leituras do clorofilômetro indicaram índice de suficiência de N < 90%, em relação ao tratamento M5; M7: aplicação de 90 kg ha-1 no dia da semeadura]. No experimento I, as cultivares de feijão-comum apresentaram diferenças para o acúmulo de MS e N durante o ciclo de desenvolvimento. O acúmulo máximo de MS e N na parte aérea das cvs. IAC Imperador, IPR Andorinha e IPR Curió ocorreu antes do que na cv. Pérola. Considerando a média dos anos, os acúmulos máximos de N nas cvs. Pérola, IAC Imperador, IPR Andorinha e IPR Curío foram de 104, 86, 99 e 92 kg ha-1 de N, respectivamente. Dessas quantidades, foram exportados pelas cvs. Pérola, IAC Imperador, IPR Andorinha e IPR Curió 80, 64, 73 e 68 kg ha-1 de N, respectivamente. No experimento II, os manejos da adubação nitrogenada de cobertura influenciaram significativamente na produtividade de grãos das cvs. IAC Imperador, IPR Andorinha e IPR Curió. A adubação nitrogenada de cobertura quando realizada no estádio de desenvolvimento V3 (M2 - 90 kg ha-1 de N em V3) e no dia da semeadura (M7 - 90 kg ha-1 no dia da semeadura), proporcionou às cultivares de feijão-comum de ciclo precoce produtividade de grãos semelhante à obtida com o manejo M5 (90 kg ha-1 de N em V3 + 90 kg ha-1 de N em R5), que recebeu o dobro da dose de N recomendada para a cultura do feijão-comum. Portanto, a adubação nitrogenada de cobertura nas cvs. IAC Imperador, IPR Andorinha e IPR Curió, deve ser recomendada até o estádio de desenvolvimento V3.
Knowledge on nutrient uptake and removal is important for the management of fertilization in agricultural crops. The objective of this work was to study dry matter (DM) accumulation and nitrogen (N) accumulation during cycle, grain yield and N removal by normal and short cycle common bean cultivars, as well as the responses of short cycle common bean cultivars to N fertilization. Two experiments were carried out in the city of Botucatu, state of São Paulo, during the years 2016 and 2017, in a Typic Rhodudalf soil. The experiment I was arranged in a randomized complete block design, with split plots and four replications. Plots were composed of four common bean cultivars [Pérola (normal cycle), IAC Imperador, IPR Andorinha and IPR Curió (short cycle)] and the subplots for seven sampling periods during the common bean development cycle (14, 28, 42, 56, 70, 77, and 84 days after emergency (DAE)). The experiment II was arranged in a randomized complete block design, with four replications. The treatments were constituted from the factorial combination 3x7, with three cultivars of short cycle common bean (IAC Imperador, IPR Andorinha, IPR Curió) and seven managements of the N fertilization [M1: without N application in coverage; M2: 90 kg ha-1 N at V3; M3: 90 kg ha-1 N at V4; M4: 45 kg ha-1 N at V3 + 45 kg ha-1 N at R5; M5: reference treatment for chlorophyll readings, with 90 kg ha-1 N at V3 + 90 kg ha-1 N at R5; M6: treatment that received N application (30 kg ha-1) only when the chlorophyllometer readings indicated a N sufficiency index <90%, in relation to the M5 treatment; M7: application of 90 kg ha-1 N on the day of sowing)]. In experiment I, common bean cultivars showed differences for DM and N accumulation during the development cycle. The maximum DM and N accumulation in the aboveground of the cvs. IAC Imperador, IPR Andorinha and IPR Curió occurred earlier than in cv. Perola. Considering the average of the years, the maximum N accumulation in the cvs. Pérola, IAC Imperador, IPR Andorinha and IPR Curio were 104, 86, 99 and 92 kg ha-1 N, respectively. These quantities, were removal by cvs. Pérola, IAC Imperador, IPR Andorinha and IPR Curió 80, 64, 73 and 68 kg ha-1 N, respectively. In experiment II, the N fertilization significantly influenced the grain yield of the cvs. IAC Imperador, IPR Andorinha and IPR Curió. N fertilization when performed at development stage V3 (M2 - 90 kg ha-1 N at V3) and on the sowing day (M7 - 90 kg ha-1 N on the day of sowing), provided the short cicle common bean cultivars grain yield similar to that obtained with management M5 (90 kg ha-1 N at V3 + 90 kg ha-1 N at R5), which received twice the recommended N rate for common bean crop. Therefore, N fertilization in cultivars IAC Imperador, IPR Andorinha and IPR Curió should be recommended up to the development stage V3.
Knowledge on nutrient uptake and removal is important for the management of fertilization in agricultural crops. The objective of this work was to study dry matter (DM) accumulation and nitrogen (N) accumulation during cycle, grain yield and N removal by normal and short cycle common bean cultivars, as well as the responses of short cycle common bean cultivars to N fertilization. Two experiments were carried out in the city of Botucatu, state of São Paulo, during the years 2016 and 2017, in a Typic Rhodudalf soil. The experiment I was arranged in a randomized complete block design, with split plots and four replications. Plots were composed of four common bean cultivars [Pérola (normal cycle), IAC Imperador, IPR Andorinha and IPR Curió (short cycle)] and the subplots for seven sampling periods during the common bean development cycle (14, 28, 42, 56, 70, 77, and 84 days after emergency (DAE)). The experiment II was arranged in a randomized complete block design, with four replications. The treatments were constituted from the factorial combination 3x7, with three cultivars of short cycle common bean (IAC Imperador, IPR Andorinha, IPR Curió) and seven managements of the N fertilization [M1: without N application in coverage; M2: 90 kg ha-1 N at V3; M3: 90 kg ha-1 N at V4; M4: 45 kg ha-1 N at V3 + 45 kg ha-1 N at R5; M5: reference treatment for chlorophyll readings, with 90 kg ha-1 N at V3 + 90 kg ha-1 N at R5; M6: treatment that received N application (30 kg ha-1) only when the chlorophyllometer readings indicated a N sufficiency index <90%, in relation to the M5 treatment; M7: application of 90 kg ha-1 N on the day of sowing)]. In experiment I, common bean cultivars showed differences for DM and N accumulation during the development cycle. The maximum DM and N accumulation in the aboveground of the cvs. IAC Imperador, IPR Andorinha and IPR Curió occurred earlier than in cv. Perola. Considering the average of the years, the maximum N accumulation in the cvs. Pérola, IAC Imperador, IPR Andorinha and IPR Curio were 104, 86, 99 and 92 kg ha-1 N, respectively. These quantities, were removal by cvs. Pérola, IAC Imperador, IPR Andorinha and IPR Curió 80, 64, 73 and 68 kg ha-1 N, respectively. In experiment II, the N fertilization significantly influenced the grain yield of the cvs. IAC Imperador, IPR Andorinha and IPR Curió. N fertilization when performed at development stage V3 (M2 - 90 kg ha-1 N at V3) and on the sowing day (M7 - 90 kg ha-1 N on the day of sowing), provided the short cicle common bean cultivars grain yield similar to that obtained with management M5 (90 kg ha-1 N at V3 + 90 kg ha-1 N at R5), which received twice the recommended N rate for common bean crop. Therefore, N fertilization in cultivars IAC Imperador, IPR Andorinha and IPR Curió should be recommended up to the development stage V3.
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Palavras-chave
Phaseolus vulgaris, Nutrição, Adubação, Biomassa, Nutrition, Fertilization, Biomass