Adubação nitrogenada de cobertura no milho cultivado em baixa altitude no inverno em linhas simples e duplas
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2020-07-29
Autores
Sousa, Junior Inacio de
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Universidade Estadual Paulista (Unesp)
Resumo
Poucos são os estudos que indicam manejos agrícolas para a obtenção de elevadas produtividades do milho semeado no inverno, ou terceira safra irrigada. O objetivo do trabalho foi avaliar a resposta do milho irrigado a doses de nitrogênio em cobertura em função de cultivo em linhas simples e duplas, em experimento conduzido em Guaíra, SP, no inverno. O solo da área experimental é um Latossolo Vermelho eutroférrico textura argilosa, o híbrido de milho utilizado foi o AG9000PRO3 e o fertilizante nitrogenado utilizado foi a ureia FH Nitro Mais. A semeadura do cereal foi realizada em 26 de julho de 2018. O delineamento experimental utilizado foi em blocos casualizados em esquema de parcelas subdivididas, com quatro repetições. As parcelas foram formadas por dois sistemas de semeadura (linhas simples e linhas duplas) e as subparcelas formadas por quatro dose de nitrogênio (aplicada em filete contínuo) em cobertura no milho: 0 kg ha-1 de N (ausência de N); 80 kg ha-1 de N com aplicação única no estádio fenológico V3; 160 kg ha-1 de N com aplicação de 80 kg ha-1 de N em V3 e V6 e 240 kg ha-1 de N com aplicação de 80 kg ha-1 nos estádios V3, V6 e V8. Após 65 dias da semeadura foi avaliado o índice de clorofila, nesse mesmo dia foi coletado amostras de folhas para análise do teor do nitrogênio na folha. Com 131 dias após a semeadura o experimento foi colhido e no mesmo dia avaliou-se: altura de planta, altura de espiga, diâmetro do colmo, diâmetro da espiga, diâmetro do sabugo, plantas acamadas, mancha de Phaeosphaeria, plantas daninhas, número de fileira por espiga, número de grãos por fileira, população de plantas, plantas quebradas, plantas dominadas, enfezamento e plantas mortas. Na colheita foi coletado amostras para análise em laboratório para as variáveis: massa de 1000 grãos, eficiência agronômica, eficiência fisiológica, eficiência agrofisiológica, eficiência de recuperação do nitrogênio, teor de nitrogênio no grão e produtividade. A maior produtividade de grãos (11.089 kg ha-1) foi obtida com a semeadura em linhas simples com a dose de 240 kg ha-1 de N parcelados em 3 vezes ao longo do ciclo do milho. O manejo de doses de nitrogênio ao longo do ciclo do milho proporcionou aumento linear da produtividade de grãos da cultura, independentemente do sistema de semeadura.
Few studies indicate agricultural management to obtain high yields of corn sown in winter, or third irrigated crop. The objective of this work was to evaluate the response of irrigated corn to nitrogen cover levels as a function of cultivation in single and double lines, in an experiment conducted in Guaíra, SP, in winter. The soil in the experimental area is claytexture Oxisol, the corn hybrid used was AG9000PRO3 and the nitrogen fertilizer used was UH FH Nitro Mais. The sowing of the cereal was carried out on July 26, 2018. The experimental design used was in randomized blocks in a split plot scheme, with four replications. The plots were formed by two sowing systems (single lines and double lines) and the subplots formed by four nitrogen doses (applied in continuous fillet) in corn cover: 0 kg ha-1 of N (absence of N); 80 kg ha-1 of N with single application at the phenological stage V3; 160 kg ha-1 of N with application of 80 kg ha-1 of N in V3 and V6 and 240 kg ha-1 of N with application of 80 kg ha-1 in stages V3, V6 and V8. After 65 days of sowing the chlorophyll index was evaluated, on that same day leaf samples were collected for analysis of the nitrogen content in the leaf. 131 days after sowing the experiment was harvested and on the same day it was evaluated: plant height, ear height, stem diameter, ear diameter, cob diameter, bedridden plants, Phaeosphaeria spot, plants weeds, number of rows per ear, number of grains per row, plant population, broken plants, dominated plants, stalking and dead plants. At harvest, samples were collected for laboratory analysis for the variables: 1000 grain mass, agronomic efficiency, physiological efficiency, agrophysiological efficiency, nitrogen recovery efficiency, nitrogen content in the grain and productivity. The highest grain yield (11,089 kg ha-1 ) was obtained by sowing in simple rows with the dose of 240 kg ha-1 of N divided in 3 times over the corn cycle. The management of nitrogen doses throughout the corn cycle provided a linear increase in the grain yield of the crop, regardless of the sowing system
Few studies indicate agricultural management to obtain high yields of corn sown in winter, or third irrigated crop. The objective of this work was to evaluate the response of irrigated corn to nitrogen cover levels as a function of cultivation in single and double lines, in an experiment conducted in Guaíra, SP, in winter. The soil in the experimental area is claytexture Oxisol, the corn hybrid used was AG9000PRO3 and the nitrogen fertilizer used was UH FH Nitro Mais. The sowing of the cereal was carried out on July 26, 2018. The experimental design used was in randomized blocks in a split plot scheme, with four replications. The plots were formed by two sowing systems (single lines and double lines) and the subplots formed by four nitrogen doses (applied in continuous fillet) in corn cover: 0 kg ha-1 of N (absence of N); 80 kg ha-1 of N with single application at the phenological stage V3; 160 kg ha-1 of N with application of 80 kg ha-1 of N in V3 and V6 and 240 kg ha-1 of N with application of 80 kg ha-1 in stages V3, V6 and V8. After 65 days of sowing the chlorophyll index was evaluated, on that same day leaf samples were collected for analysis of the nitrogen content in the leaf. 131 days after sowing the experiment was harvested and on the same day it was evaluated: plant height, ear height, stem diameter, ear diameter, cob diameter, bedridden plants, Phaeosphaeria spot, plants weeds, number of rows per ear, number of grains per row, plant population, broken plants, dominated plants, stalking and dead plants. At harvest, samples were collected for laboratory analysis for the variables: 1000 grain mass, agronomic efficiency, physiological efficiency, agrophysiological efficiency, nitrogen recovery efficiency, nitrogen content in the grain and productivity. The highest grain yield (11,089 kg ha-1 ) was obtained by sowing in simple rows with the dose of 240 kg ha-1 of N divided in 3 times over the corn cycle. The management of nitrogen doses throughout the corn cycle provided a linear increase in the grain yield of the crop, regardless of the sowing system
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Palavras-chave
Zea mays, Arranjo espacial, Fertilizante nitrogenado, Cultivo irrigado, Produtividade de grãos, Eficiência agronômica