Demanda De Nutrientes Pelo Milho Safrinha Em Função Da Época De Semeadura E Adubação

Abstract

RESUMO -No Brasil Central, a produtividade e a demanda nutricional do milho em sucessão à soja cultivada no verão são dependentes das condições climáticas ao longo do ciclo. Sendo assim, objetivou-se com esse trabalho quantificar a extração e exportação de nutrientes pelo milho, em função da época de semeadura e da adubação fornecida na safrinha de 2014, em Rio Verde-GO. Em cada época de semeadura (29/01/2014 e 25/02/2014) foi conduzido um experimento em delineamento de blocos casualizados, com quatro repetições, num esquema fatorial 4x2, sendo quatro adubações de semeadura (00-00-00, 00-50-50, 25-50-50 e 50-50-50 kg ha -1 de N-P 2 O 5 -K 2 O), com ou sem adubação nitrogenada em cobertura (0 ou 50 kg ha -1 de N). Ao final do ciclo, foram avaliados o rendimento de grãos e o acúmulo de nutrientes nos componentes da parte aérea. Foram determinadas a extração e a exportação de nutrientes. O desenvolvimento e a extração de nutrientes pelo milho safrinha são influenciados pela época de cultivo, assim como pela adubação nitrogenada em cobertura, sem, contudo, ser afetados pela adubação NPK realizada na semeadura. Há maior produção de biomassa seca e produtividade de grãos com a semeadura em janeiro em comparação a fevereiro. O cultivo na primeira época e o nitrogênio em cobertura resultam em maior extração da maioria dos nutrientes, sem necessariamente implicar maiores taxas de exportação com a colheita dos grãos. Em média, a exportação por tonelada de grãos produzida foi de 14,2; 1,5; 2,8; 0,07; 0,7 e 1,0 kg de N, P, K, Ca, Mg e S; e de 2; 12; 4 e 16 g de Cu, Fe, Mn e Zn, respectivamente. Esses valores implicam doses relativamente baixas de fertilizantes na adubação de manutenção para repor a exportação na colheita do milho safrinha. Palavras-chave: sucessão de culturas, extração, exportação, requerimentos nutricionais, Zea mays L. OFF-SEASON CORN NUTRIENT DEMAND ACCORDING TO THE SOWING DATE AND FERTILIZATIONABSTRACT -In Central Brazil, productivity and nutritional demand of corn in succession to soybeans grown in summer are dependent on climatic conditions throughout the cycle. Therefore, the objective of this work was to quantify the extraction and exportation of nutrients by off-season corn, according to the sowing date and fertilization in Rio Verde, State of -Goiás, Brazil. In each sowing time (01/29/2014 and 02/25/2014), a randomized complete block design experiment was carried out, with four replications, in a 4x2 factorial scheme, with four sowing fertilizations (00-00-00, 00 -50-50, 25-50-50 and 50-50-50 kg ha -1 of N-P 2 O 5 -K 2 O), with or without nitrogen fertilization (0 or 50 kg ha -1 N). At the end of the cycle, grain yield and nutrient accumulation in shoot components were evaluated. The extraction and export of nutrients were determined. The growing season and the sidedress nitrogen influence the development and extraction of nutrients by the off-season corn, without, however, being affected by the NPK fertilization at sowing. There is higher production of dry biomass and grain yield with sowing in J...

Nitrogen fertilization in off-season corn crop in different Brazilian Cerrado environments

“…In addition, there is high weather variability regarding solar radiation and air temperature, inhibiting the photosynthetic metabolism and yield potential of the corn plants (Nóia Júnior & Sentelhas, 2019b). Although modern cultivars are physiologically able to uptake high amounts of N (Bender et al, 2013;Silva et al, 2018), there is less need for fertilization in the off-season, compared with the spring-summer cropping, due to the lower yields achieved (Ragagnin et al, 2010;Soratto et al, 2010;Simão et al, 2017).…”

“…The removal of N was determined considering the average rate of 13.1 kg Mg -1 exported in the harvested grains of the off-season corn crop (Duarte et al, 2019) and the correspondent yield achieved in each condition. These yields were also used to estimate the amount of N extracted by corn, considering the average rate of 21.7 kg Mg -1 reported for off-season crops (Simão et al, 2017).…”

Agronomic Performance of Corn Cultivars as a Function of Phosphorus Use

“…On the other hand, in the reproductive period the largest extraction is of N, followed by K and P [7]. For each ton of grain produced, a mean of 14.2 kg of N, 1.5 kg of P, and 2.8 kg of K are exported [8].…”

“…The reduction in nutrient removal values by modern corn cultivars shows probable gains inuse efficiency [8]. However, there is still little information on the behavior of cultivars at different phosphorus levels, especially in the state of Pará.…”

Non-nutritional biostimulant improves maize cultivation economic parameters

“…Although maize cultivation in second season provides high productivity when carried out under irrigation conditions, resulting in adequate financial return to the producer (Souza et al 2012), this is not the reality of most properties. In these cases, the production is dependent on the rains that occur during the vegetative plants development (Simão et al 2017). Thus, in years with water shortage, maize plants develop in an irregular way, with decrease of photosynthetic activities and, consequently, productive losses (Melo et al 2018;Tůmová et al 2018).…”