Fiorini et al. Nitrogen fertilizations via leaf on soybean stages and nitrogen released on yield of off season maize 33

Advanced agricultural techniques have considerably increased soybean yield, but have led to the depletion of micronutrients in soils without adequate replenishment and have a key role in the maintenance and / or attainment of high yields in the soybean crop. Thus, the objective of this work was to determine the soybean yield components as a function of different doses and times of application of Cobalt (Co) and Molybdenum (Mo) via leaf. The experiment was conducted at the Celeste Farm, in Vera - Mato Grosso. Two applications of Co and Mo were made in the culture with the following doses of 0, 50, 100, 150 and 300 mL, the first application occurred in the V5 stage (fourth fully developed trifoliate leaf), and the second application in R2 (flowering full). A cultivar BRS811CRR was used in 40 plots of 11.25 m². The following variables were evaluated: plant height, dry mass, one hundred grain mass, number of pods per plant, grains per pod and productivity. The agronomic characteristics of the plants were not altered by the application of molybdenum cobalt via leaf, in the different stages of development of the soybean crop.

RESUMO O cultivo da soja exige um alto nível de qualidade em relação às sementes empregadas, além de ser muito dependente da condição hídrica. Dentro dessa sistemática, este estudo avaliou o impacto do déficit hídrico na germinação de sementes na cultura de soja. Foram avaliados 12 tratamentos, com 4 repetições em cada, totalizando 50 sementes de soja por repetição, em que se comparou o rendimento das sementes tratadas industrialmente com standak top 200 ml a cada 100 kg de sementes (piraclostrobina 25g/l + tiofanato metílico 225g/l + fipronil 713g/l), com fungicidas em comparação com as sementes não tratadas. Os resultados obtidos evidenciaram que a ausência de água até 14 dias não impactou na produtividade e rendimento produtivo das plântulas. No entanto, após esse período, a ausência de umidade influenciou na qualidade fisiológica das sementes, comprometendo o stand final. As análises feitas acerca da influência da temperatura e umidade foram pouco significativas. Outra conclusão deste experimento foi que as sementes tratadas obtiveram um resultado aquém do obtido pelas sementes não tratadas. Pressupõe-se, a partir das análises feitas, que o tratamento empregado nas sementes tratadas industrialmente não tenha sido realizado de forma adequada, causando fitotoxidez na semente ou injúrias causadas no momento da inserção da mistura que comprometeram a qualidade fisiológica e química da semente tratada e, por essa razão, seu rendimento não sobrepujou o obtido pelas sementes não tratadas.

Physiological conditioning is a technique that consists in controlling the speed of water uptake by seeds, with osmotic solutions, aiming to improve their quality, reducing time and increasing germination rate. Eremanthus erythropappus (D.C.) MacLeish seeds were subjected to priming with polyethylene glycol 6000 (PEG), potassium nitrate (KNO3) and the combination of the two at the concentrations of 0.4; -0.8; -1.0; -1.2 and -1.4 MPa for four, six and eight days. Germination, germination speed index (GSI), emergence, emergence speed index (ESI) and expression of superoxide dismutase (SOD), catalase (CAT) and peroxidase (PO) enzymes were assessed. E. erythropappus seed priming in polyethylene glycol solution with potentials between -0.8 MPa and -1.4 MPa is not satisfactory because it adversely affects germination and reduces the activity of peroxidase and catalase enzymes. The other substances were not significant so there is a need for further research with other substances and / or concentrations