Sowing date and maturity group in soybean grown in lowlands

ABSTRACT It is projected an increase of about 30% in the world population by 2050 and a food demand increase by 60%, mainly vegetable proteins. Due to this, soybean is being introduced in new production systems, such as in rotation with irrigated rice in lowlands. Irrigated and non-irrigated experiments were conducted in order to determine the influence of irrigation on maturity groups, on yield components and yield in lowlands. Five soybean cultivars with maturity groups (MG) ranging from 4.8 to 7.8 were used, representing the cultivars sowing in southern Brazil, and three sowings were performed (October, November and January). A decrease in the number of pods m-2 was observed with the delay in the sowing date in both water regimes and MG, except MG 4.8 and 5.5, which had a higher number of pods m-2 when irrigated and sown in November. The leaf area index (LAI) was higher under the irrigated condition, for all MGs and sowing dates. The interaction between the yield components can be maximized by the combination of supplemental irrigation, anticipation of sowing date and the choice for cultivars with MG from 6.2 to 6.8 for lowland environments.