Plastochron in soybean cultivars under the space arrangements

The plastochron is an important parameter in the use of agricultural modeling for annual crops. The objective of this study was to determine the plastochron soybean cultivars in different spatial arrangements. Two experiments were conducted in the field, one in the crop year 2012/2013 and other 2013/2014. The cultivars used were BMX Ativa RR, BMX Turbo RR e BMX Potência RR and spatial arrangements 45, crossed, 20, 20x40, 20x60, 20x80 cm, with three replications. The center row of each plot after emergence marked up five plants, and in these counted the number of visible nodes on the main stem twice a week, emergency until the issuance of the last node, determining also, its phenological stage. The plastochron ranged from 57.27 to 77.19 °C day node-1 among cultivars in two years. The first crop year 2012/2013 showed meaningful differences for all cultivars. In the second crop year (2013/2014), only 20x40 and 20x60 cm there are no meaningful difference between cultivars. In this cultivation, there was the inverse of the previous year, compared to the cultivars, beyond the differences are not as meaningful as in the previous year. In conclusion, the plastochron varies with cultivars, spatial arrangements and crop years. It is suggested to further study with new soybean cultivars in different arrangements, so that you can use this data in agricultural modeling.