The development of technologies to increase stand establishment efficiency and seed vigor, as well as to maximize profits, is of fundamental importance for the sustainability of agriculture. Products based on humic substances, such as humic acids, have been recently used in Brazilian agriculture to produce seedlings with high vigor, which positively influences the establishment of the initial stand. Thus, this study aimed to evaluate the effect of treatment of corn seeds with a commercial humic acid-based product, Humykos® (18% of humic acid content), on germination and seedling vigor. The treatments consisted of six doses (0, 100, 200, 300, 400, and 500 mL 100 kg-1 seed) of Humykos®, and the treated seeds were analyzed for germination and vigor (first count, emergence, emergence speed index, length, and dry mass of shoots and roots). Our results show that humic acid promotes greater seedling growth and increased shoot dry mass in corn; in addition, it has a positive influence on the emergence speed index up to a dose 158 mL 100 kg -1 seeds.

Inúmeros trabalhos têm demonstrado o efeito benéfico da adubação com silício sobre o acréscimo da produção de diversas culturas, como, por exemplo, arroz, cana-de-açúcar e batata. No entanto, são escassas as informações sobre os benefícios nutricionais do silício para a cultura do milho. Desta maneira, objetivou-se, neste estudo, avaliar o efeito de doses e épocas de aplicação de silício, via foliar, nas características agronômicas e na produtividade do milho, cultivado no ano agrícola 2007/2008. O delineamento experimental adotado foi o de blocos casualizados, em esquema fatorial (4 x 3) + 1, com quatro repetições, envolvendo doses de silício (130, 260, 390 e 520 g ha-1 de Si) aplicadas via foliar, épocas de aplicação (2, 5 e 8 folhas expandidas) e uma testemunha (sem aplicação de Si). As variáveis analisadas foram altura das plantas e a inserção da primeira espiga, diâmetro de colmo, índice de clorofila foliar, teor foliar de silício, número de grãos por espiga, massa de 100 grãos e produtividade de grãos. O silício aplicado via foliar influenciou somente o teor foliar de Si.

The aim of the present study was to evaluate the effects of temperature, substrate, and luminosity on chia seeds in order to determine adequate conditions for a germination test. The experiment consisted of a completely randomized design, in a 4 × 5 × 2 factorial scheme (four substrates × five temperatures × two luminosity conditions), with four replications. The following variables were analyzed: first germination count, germination, germination speed index, and mean germination time. Germination was best at 15, 20, 25, and 30 °C for the on-paper, paper roll, and sand substrates. However, in the presence of luminosity and at 25 °C, the on-paper substrate had the highest mean. For all substrates, the lowest germination was achieved at 35 °C, proving that high temperatures reduce chia seed germination. Germination speed index was highest at 25 and 30 °C for on-paper, paper roll, and sand substrates, in both the presence and absence of luminosity. Chia seeds are considered to be neutral photoblasts. Germination tests should be performed with the on-paper substrate, at 25 °C, and with a duration of seven days. The first count should be carried out four days after establishment of the test.

Chia (Salvia hispanica) is an annual oilseed crop of high nutritional value. This study aimed to analyze the performance of chia plants sown at different times and grown under different phosphorus rates. The experiment was conducted under field conditions at the Experimental Farm of the State University of Maringá, Umuarama, Brazil. Treatments were arranged in a randomized split-plot design with three replications. Phosphorus fertilizer was applied at the time of sowing at rates of 0, 40, 80, or 120 kg P2O5 ha−1. Seeds were sown on four dates at 14-day intervals, starting on March 21, 2017, for the first crop and March 29, 2018, for the second crop. Plant population density, raceme number, shoot dry matter yield, thousand seed weight, seed yield, and seed oil content were determined. It was observed that the end of March is the borderline for chia cultivation, because the low temperature and rainfall conditions occurring after this period compromise chia growth. The best phosphorous rate for chia growth was 80–120 kg ha−1, which led to optimum vegetative parameters.

This work aimed to evaluate the effects of using management of growth regulator trinexapac-ethyl (Moddus^®)) over plant height, lodging, productivity and grain yield of soybean plants (Glycine max (L.) Merrill. cv. BS 2606 IPRO). For that, an experiment was installed in field conditions, by using a randomized block design, with four replications; experimental unit was constituted of five lines of four meters in length, spaced at 0.45 m. Treatments were constituted by the application of growth regulator, as follows: without application; total dose between V3 and V4; total dose between V5 and V6; ½ dose between V3 and V4 + ½ dose between V5 and V6; total dose between V3 and V4 + total dose between V5 and V6, totaling five treatments. Productive components, mass of 100 grains and grain yield were evaluated. Results were not significant for studied variables regardless of management, differing only from the control. Keywords: oilseed; lodging; plant regulator; application management; grain yield.   RESUMO: Esse trabalho teve por objetivo avaliar os efeitos da utilização de manejos do regulador de crescimento (trinexapac-ethyl (Moddus^®)) sobre altura, acamamento, produtividade e rendimento de plantas de soja (Glycine max (L.) Merrill. cv. BS 2606 IPRO). Com isso, instalou-se um experimento em condições de campo, com o delineamento experimental de blocos casualizados, com quatro repetições; a unidade experimental constituiu-se de cinco linhas de quatro metros de comprimento, espaçadas em 0,45 m entre elas. Os tratamentos foram constituídos pela aplicação do regulador de crescimento, sendo: sem aplicação; dose total entre V3 e V4; dose total entre V5 e V6; ½ dose entre V3 e V4 + ½ dose entre V5 e V6; dose total entre V3 e V4 + dose total entre V5 e V6, perfazendo cinco tratamentos. Foram avaliados os componentes produtivos, massa de 100 grãos e produtividade. Os resultados não foram estatisticamente significativos para as variáveis avaliadas independente dos manejos, diferindo apenas da testemunha. Palavras-chave: oleaginosa; acamamento; regulador vegetal; manejo de aplicação; produtividade.