Estimated length of soybean phenological stages

Abstract

The use of modeling is a trend for agronomic science that aims to detect factors that could limit the growing practices and influence the potential yield of some crops. The objective of this study was to calculate the accumulated thermal time and estimate the phenological stages length of three soybean cultivars in two crop years, using agronomic models associated to meteorological variables. Two experiments were conducted in a field at the Agroclimatology Laboratory (LAGRO) of the Federal University of Santa Maria/UFSM, campus of Frederico Westphalen/RS, Brazil during the 2012/2013 and 2013/2014 crop years. A randomized block in a factorial scheme 6x3 with six spatial arrangements (45, crossed, 20, 20x40, 20x60 and 20x80 cm) and three cultivars with different cycles and growth habits (BMX Ativa RR/determinate, BMX Turbo RR/indeterminate and BMX Potência RR/indeterminate) with three replications were used for the experimental design. Sowing was held on 11/28/2012 and 12/02/2013. The assessed phenological stages were sowing-emergence; emergence -final vegetative; final vegetative -full bloom; full bloom -physiological maturity. The duration of each stage was related to meteorological parameters: maximum temperature, minimum temperature, average temperature, rainfall, solar radiation, and thermal time. Air temperature influences soybean growth and development. The accumulated thermal time varies between years and among cultivars, and it is the main contributor to the estimated duration of the phenological stages. Key words: Weather elements. Glycine max L. Merrill. Agronomic models. Thermal time. Temperature. ResumoA utilização de modelagem é uma das tendências da ciência agronômica que objetiva detectar os fatores que possam limitar o cultivo e influenciar no potencial de rendimento das culturas. O objetivo deste trabalho foi calcular a soma térmica acumulada e estimar a duração das fases fenológicas de três cultivares de soja em dois anos agrícola, por meio de modelos agronômicos associados às variáveis meteorológicas. Dois experimentos foram conduzidos no campo experimental do Laboratório de Agroclimatologia (LAGRO) da Universidade Federal de Santa Maria/UFSM, campus Frederico Westphalen/RS nos anos agrícolas de 2012/2013 e 2013/2014. O delineamento experimental usado foi de blocos casualizados em esquema fatorial 6x3, ou seja, seis arranjos espaciais (45, cruzado, 20, 20x40, 20x60 e 20x80 cm) e três cultivares de ciclos e hábito de crescimento distintos (BMX Ativa RR/determinada, BMX Turbo RR/indeterminada e BMX Potência RR/indeterminada) com três repetições. As semeaduras foram realizadas nos dias 28/11/2012 e 02/12/2013. As fases fenológicas avaliadas foram: semeadura -emergência; emergência -vegetativo final; vegetativo final -floração plena; floração plena -maturação fisiológica. Relacionaram-se a duração de cada fase com os elementos meteorológicos: temperatura máxima, temperatura mínima, temperatura média, precipitação, radiação solar e soma térmica acumulada. A temperatura do ar influencia no ...

Effect of Sowing Date on Soybean Development in South-Western Poland

“…Temperature is closely related to the metabolism of plants, i.e., their growth speed, as well as the chronological duration of subsequent development phases. Temperature combined with photoperiodism initiates the flowering phase [6,7]. It was shown that photoperiod and temperature interact with the genotype to control soybean growth and development throughout the growing season [8,9].…”

Sowing date changes phenological development, plastochron index, and grain yield of soybeans under Cerrado conditions

“…Regarding the duration of the phenological stages, cultivars with longer cycles were more sensitive to the duration of subperiods than those with shorter cycles (Rockenbach et al, 2016). This variation was more evident from the vegetative period to the beginning of grain filling (V E -R 5.1 ).…”

“…F values and averages for plastochron index (°C day node -1 ) according to the treatments † Values followed by the different letters in the columns are statistically different at (p < 0.05) according to the LSD test Table 3. Interactions between cultivar and sowing dates for plastochron (°C day node -1 ) in first and second year † Values followed by the same lowercase letter in the columns and uppercase letters in the rows are statistically different at (p < 0.05) according to the LSD test According to Rockenbach et al (2016), the shortening of the cycle and the precocity for flowering are characteristics that occur due to the reduction of the photoperiod and the occurrence of high temperatures, as observed in the years studied, mainly in the vegetative growth phase.…”

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Estimation of the Optimum Size of Plots for Soybean Radiometer Experiments

“…However, higher than estimated by Michels el al. (2016), who developed the study to analyze the effect of different numbers of fungicide application on soybean, using 5.4 m² plots and by Rockenbach et al (2016), who estimated the duration of the phenological phases of soybeans and adopted plots of 6.75 m² in area.…”