Época de semeadura do milho para a região de Sete Lagoas, MG, baseada na probabilidade de ocorrência de períodos secos e chuvosos

Abstract

Corn sowing time in Sete Lagoas region, Minas Gerais State, based on the probability of occurrence of dry and rainy spellsThe objective of this study was to determine the probability of dry and rainy occurrence periods in Sete Lagoas, Minas Gerais State, Brazil, from a historical series of 66-year-long daily rainfall data to establish the best sowing date for corn crop. Dry days were considered as those that had precipitation below corn evapotranspiration, ET corn . This study was carried out for the stages of flowering and grain filling, starting from seven sowing times ST (10/01, 10/16, 10/31, 11/15, 12/01, 12/16 e 12/31). The probabilities of occurring dry and rainy spells were estimated by the Markov´s chain. The probability of occurring dry days was always higher than rainy days. The highest probability of dry days were found between ST 15/11 and DS 31/12. The highest probability of occurring rainy days was recorded at ST 01/10. Considering the studied average cycle (for the most critical stage of corn development), the combination of the lowest probability of dry spells with the highest probability of rainy days indicates that the best dates to initiate non-irrigated sowing should be ST 01/10 and 16/10.

Cultivares De Milho Afetadas Pela Época De Semeadura Na Safrinha Em Tocantins

“…O atraso da semeadura na safrinha do Tocantins reduz a quantidade de chuvas disponível durante o ciclo da cultura, o que resulta em decréscimo do potencial produtivo. As fases mais críticas das plantas de milho como relação à exigência hídrica se concentram na emergência, no florescimento e no enchimento dos grãos (Silva et al, 2010 …”

Agronomic performance of eight corn genotypes in two sowing periods

“…The maximum temperature obtained in the sowing periods varied from 28.4 to 33.1 °C, and the minimum temperature from 21.6 to 23.5 °C (Figures 1 and 2). Silva et al (2010), also found that the most critical phases of corn plants, concerning water requirements, are concentrated on emergence, flowering, and grain filling. As stated by these authors, periods of water shortages of one week, in the bolting phase, may reduce grain production by up to 50%, whereas under the same conditions, water deficiency after the beginning of grain formation may cause losses between 25 and 37%.…”

“…Vários trabalhos demonstraram que o milho pode ser cultivado no Brasil em diferentes épocas de semeadura (SILVA et al, 2010;UATE et al, 2015;COSTA et al, 2017), como no início do período chuvoso para a região, de setembro a novembro, conhecido como safra e, no final do período chuvoso para a região, nos meses de fevereiro e março, conhecido como safrinha. Entretanto, para o estado do Amazonas tem-se poucas informações sobre o efeito das épocas de semeadura para o cultivo de milho.…”

“…Agronomic performance of eight corn genotypes in two sowing periods Several studies have shown that corn should be grown in Brazil at different sowing periods (SILVA et al, 2010;UATE et al, 2015;COSTA et al, 2017), for the region, at the beginning of the rainy season, from September to November, known as harvest season, and at the end of the rainy period, in February and March, known as the off-season. However, for the state of Amazonas, there is little information on the effect of sowing times for corn cultivation.…”

Aplicação da Cadeia de Markov para Dias Secos e Chuvosos

“…Posteriormente, utilizou-se a Cadeia de Markov de 1°ordem, por meio do aplicativo Instat Climatic (Stern et al, 2006), para se determinar as probabilidades condicionais de ocorrência de dias secos e chuvosos. Assim, os dias secos e chuvosos foram divididos em quatro subgrupos: a) dia seco com o dia anterior seco (SS), b) dia seco com o dia anterior chuvoso (SC), c) dia chuvoso com o dia anterior chuvoso (CC) e d) dia chuvoso com o dia anterior seco (CS) (Keller Filho et al, 2006;Silva et al, 2010;Moura et al, 2015). Cada ano (Q i ) pode ser descrito com uma sequência de dias secos (x j = 0) ou chuvosos (…”