Sucessão soja-milho safrinha em função do arranjo de épocas de semeadura e ciclos de maturação da soja

Abstract

Among crops grown in Brazil, soybean(Glycine max (L.) Merrill) and corn (Zea mays) occupy a prominent area, being the two main commodities. That is why it is essential to understand the best positions of these crops, aiming at the viability of the soybean-corndouble summercrop arrangement. The objective of this research was to understand the effect of soybeansowing periodsof different groups of maturation in relation to its agronomic performance,as well as of corn grown as asecond summer crop, forbetter recommendation of the soybean –corn double summer croparrangement in the Southwest of Paraná.Experiment was carried out at the experimental research station f the Federal Technological University of Paraná, Campus of Dois Vizinhos (UTFPR-DV)atthe 2018/2019 growing season. Experimental design usedwas randomized blocks, in a factorial scheme, with three replications; where factor A was composed of three soybean cultivars (P95R51 RR®, P95Y52 RR®and P96Y90®), and factor B for three sowing dates (ES) (09/11; 10/05and 10/16). Corn hybrid P3380HR®was sowed at the same day as soybean was harvest, totaling9 sowing periods.It should be noted that the 2018/19 growing seasonwas very atypical in terms of weather conditions, with a long period of drought at December and January, which ended up affecting soybean crops differently. Soybean genotypes with ripening group 5.1 and 5.2 (95R51 and 95Y520) sown atSeptember (September 12th) and early October are the most suitableonestoturn it viable thegrown of corn as a 2ndsummer crop, since it has satisfactory yield, and the sowing of corn can be done in late January or early February, where it will perform well in terms of grain yield. As for soybean sowing in the middle of October, which is the reality of the farmers that growssoybean afterwheat, with the exception of the 95R51® cultivar, there is a decrease in soybean yieldand also it makesunfeasible to grow thecorn as a 2ndsummer crop. Thus, soybean cultivar 96Y90with the 6.0 ripening group sowed at mid-September is a goodoption once make it possible to sown cornwithin its agricultural zoning. The mild temperatures and the low solar radiation from the month of May, make the grains take a longtime to loseits moisture, contributing to the low physiological quality of the corn grains. It is also suggested the adoption of a combinationbetween soybean sowing periods and ripening group and corn hybridsto reduce climatic risks and provide greatersecurity in the production system.