Produtividade de híbridos de milho em função de épocas de semeadura e doses de nitrogênio

Abstract

New corn hhybrids with precocity associated with the anticipation of the sowing season have allowed the cultivation of a 2 nd summer crop. However, it is essential to understand the risks inherent to this decision­making as well as how the genotypes vs environment interactions affect yield potential, as well as the potential response to nitrogen levels. An experiment was laid out factorial system (2 x 2 x 2) in a randomized block design with 5 replications. There were three factors: 2 hybrids (P3016VYHR and P3707VHY), 2 sowing periods (08/24 and 09/10/22) and two nitrogen rates (140 and 180 Kg of N ha­-1). Due to the crop season (2021/22) weather conditions (high temperatures and only 50 mm of rain in November and December), corn sowed in August showed 2.057 kg ha­-1 higher yield when compared to the sowing at September. The hybrid P3016VYHR showed higher yield (9,451 kg ha­-1) when compared to the hybrid P3707VYH (8,062 kg ha­-1). These yield difference represent more than R$ 2,300.00 in net income per hectare in the 2021/22 crop season simply due to the sowing period. The long period of drought affected the productive potential of corn, which ended up not responding to the highest dose of nitrogen (180 kg ha-­1), making it possible to infer that in La Ninã years, farmers should be more conservative in relation to nitrogen management. Furthermore, sowing in August enables the cultivation of a second summer crop (soybean/beans off season), while sowing in September makes this alternative unfeasible, opening an off­season for the adoption of summer cover crops. Considering that each year is different from the other, and looking at the results of this work, in order to dilute production risks, it is recommended to diversify the production system, working with more than one hybrid and sowing times, although earlier sowing is a feasibly alternative for the productive system.