In terms of land, the world area cultivated with sweet corn is approximately 1.04 million hectares. The United States of America is the country with the largest productive area of about 100,000 hectares and an average yield of 8.09 t ha^-1 (^{USDA, 2017}). The Brazilian scenario does not present great popularity for sweet corn, although edaphoclimatic conditions contribute to a productivity of more than 13.00 t ha^-1 (^{Luz et al., 2014}), the technological cultivation conditions maintain productivity below those observed in countries such as the USA, with around 17.17 t ha^-1 (^{FAO, 2018}).

The use of biostimulants in coffee seedlings can promote gains in their growth and quality. Thus, this study aimed to evaluate the growth and quality characteristics of Coffea arabica seedlings under the effect of the nicotinamide and Azospirillum brasilense application. The experimental design was randomized blocks with treatments arranged in a 5 × 2 factorial scheme, with four replicates. The treatments resulted from the use of five doses of nicotinamide (0, 30, 60, 90, and 120 mg L-1 of water) combined with the absence and presence of Azospirillum brasilense applied to Coffea arabica seedlings from Catuaí Vermelho 144 cultivar. Plant height, stem diameter, number of leaves, leaf area, shoot dry mass, root dry mass, plant height:stem diameter ratio, shoot:root dry mass ratio, plant height:shoot dry mass ratio, and Dickson quality index were evaluated. The combined or isolated use of A. brasilense and nicotinamide, up to a dose of 33.5 mg L-1, increased the biometric characteristics and dry mass accumulation. However, using nicotinamide doses between 30 and 61.8 g L-1 increased the quality of Coffea arabica seedlings. The synergistic effect of the use of A. brasilense and nicotinamide was verified for the growth and quality of Coffea arabica seedlings.

In the conilon coffee tree, the stress caused by high light can reduce the photosynthetic rate, limit the development and also reduce the yield of beans. Considering that the quality of a sunscreen spray can influence photosynthetic performance, the goal was to understand the iterations between the quality of the spray and the variation of the chlorophyll a fluorescence when applying sunscreen on conilon coffee trees. The parameters coverage, volumetric median diameter, density, droplet deposition, and the variation of the chlorophyll a fluorescence were evaluated. The nozzle and application rate factors did not show direct effects in the physiological responses of the plants. Plants with no sunscreen application showed high values of energy dissipation flux. The photosystem II (PSII) performance index and PSII photochemical maximum efficiency indicate that the use of sunscreen for plants promotes better performance of photosynthetic activity and that it provides photoprotection against luminous stress, regardless of the application rate and spraying nozzle; however, we recommend using the application rate of 100 L ha⁻¹ and the cone jet nozzle type because they provide lower risks of product loss due to runoff.

O fogo é um instrumento de manejo em diversos tipos de ecossistemas, já que atua como importante agente mineralizador do solo. O objetivo deste trabalho foi comparar ocomparar o efeito da queima de resíduos sobre as propriedades quimicas do Latossolo vermelho distrófico do Cerrado.

Soil microbiological indicators are essential tools to understand how the management with cover crops interferes in the activity and the soil microbial community. Thus, the objective of the study was to evaluate microbiological attributes and performance of the bacterial community in the soil of the Brazilian Cerrado with different cover crops. The experiment was performed in a randomized block design, evaluating seven cover crops, Sorghum bicolor, Crotalaria ochroleuca, Pennisetum americanum, Panicum miliaceum, Raphanus sativus, Urochloa brizantha, Urochloa ruziziensis, and a fallow area. Cover aerial biomass dry weight (CB), microbial biomass carbon (MBC), basal soil respiration (BR), metabolic quotient (qCO₂), and abundance and structure of bacterial community based on the rrs 16S rRNA gene were evaluated. In the soil cultivated with S. bicolor there was the highest CB and MBC at the same time as there was less microbial activity (lower BR and qCO₂). The structure of the bacterial community was more differentiated in soils cultivated with S. bicolor, P. americanum, and C. ochroleuca. The MBC was more associated with cover crops of the Urochloa genus, while BR was positively correlated with S. bicolor. Bacterial abundance was positively correlated with P. miliaceum.

The objective of this study was to evaluate the growth and yield of radishes in response to cotton residue doses and biostimulant application. The experimental design was in randomized blocks in a 5 x 2 factorial scheme using the doses of 0; 25; 50; 75; 100 t ha-1 of cotton residue with or without biostimulant, with three replicates. At 32 days after emergency, the following variables were determined: plant height, leaf area, diameter of commercial roots, diameter of non-commercial roots, fresh mass of commercial roots, fresh mass of non-commercial roots, root dry mass, and dry mass of the plant leaves. Increases ranging from 49.74 to 1.291% were observed depending on the analyzed variable in comparing the control with the highest residue dose of 100 t ha-1. The biostimulant application treatments were up to 25.75% superior in relation to the treatments without application. It is concluded that cotton residue application and biostimulant are good alternatives to improve the performance of radish plants and can be used in organic production systems.