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Protected environment and substrate, as well as interaction between both, influence the formation of pepper seedlings and promote adequate plant growth. The present study evaluated different types of protected environments and substrate compositions in the initial growth of "Guaraci Cumari do Pará" pepper (Capsicum chinense) seedlings. The experiment was conducted in a completely randomized design, in a 4 x 5 factorial scheme (4 protected environments x 5 substrate compositions). Agricultural screenhouses with black polyethylene screens of 18% and 30% shading and agricultural greenhouses with polyethylene screens of 35% and 42-50% shading under the plastic film were used. In the environments, substrates 100% Carolina Soil® + 0% vermiculite, 80% Carolina Soil® + 20% vermiculite, 60% Carolina Soil® + 40% vermiculite; 40% Carolina Soil® + 60% vermiculite and 20% Carolina Soil® + 80% vermiculite were tested. The environment that provided higher growth for all substrates was with 35% shading, which increased seedling quality 2.9 times. In the 30% shading environment, better performance of the substrate (80% Carolina Soil® + 20% vermiculite) was observed, while in the 35% shading environment, better performance of the commercial substrate (100% Carolina Soil®) was observed, with greater plant height, stem diameter, number of leaves, and dry biomass. However, the 35% shading environment increased 2.4 times the quality of seedlings with the commercial substrate, regarding 40% Carolina Soil® + 60% vermiculite. Regarding seedling quality, the best substrate was the commercial substrate, i.e., 95% superior to 40% Carolina Soil® + 60% vermiculite in the average environment. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the effect of the dose and source of nitrogen (N) fertilizers on plant vegetative growth, productivity, and quality of onion bulbs in the conditions of the Brazilian Cerrado. For this purpose, the experimental design included three doses of N (50, 100 and 150 kg N ha-1, corresponding to 50, 100 and 150% of the recommended dose, respectively), and two N sources (urea, 45% of N; and and ammonium sulfate, 20 % of N). It was verified that the increment of N doses resulted in more vigorous plants and, consequently, in greater productive gains. In addition, it was found that the use of ammonium sulfate provided a 37.2% increase in bulb weight and total productivity and a 59.6% increase in the productivity of Class III marketable bulbs compared to urea. In addition, it was concluded that, for onion cultivation under tropical conditions, like in the present study, the use of a dose equivalent to 150% of the recommendation for onion provides better productive performance of the crop, especially when associated with the use of sulfate ammonium as N source. [ABSTRACT FROM AUTHOR]