The reduction of pesticide spraying drift is still one of the major challenges in Brazilian agriculture. The aim of this study was to evaluate the potential of different adjuvant products, such as surfactants, drift retardants, mineral oil and vegetable oil for reducing drift in agricultural spraying. The experiment consisted of quantifying drift of sprayings of 18 adjuvants dissolved in water under controlled conditions in a wind tunnel. Tests were performed in triplicates with spraying nozzles type Teejet XR8003 VK, pressure of 200kPa and medium drops. Solutions sprayed were marked with Brilliant Blue dye at 0.6% (m v-1). The drift was collected using polyethylene strips transversally fixed along the tunnel at different distances from the nozzle and different heights from the bottom part of the tunnel. Drift deposits were evaluated by spectrophotometry in order to quantify deposits. The adjuvants from chemical groups of mineral oil and drift retardant resulted in lower values of drift in comparison with surfactants and water. The results obtained in laboratory show that the selection of appropriate class and concentration of adjuvants can significantly decrease the risk of drift in agricultural spraying. However, the best results obtained in laboratory should be validated with pesticide under field conditions in the future.

This study defined the main adjuvant characteristics that may influence or help to understand drift formation process in the agricultural spraying. It was evaluated 33 aqueous solutions from combinations of various adjuvants and concentrations. Then, drifting was quantified by means of wind tunnel; and variables such as percentage of droplets smaller than 50 μm (V50), 100 μm (V100), diameter of mean volume (DMV), droplet diameter composing 10% of the sprayed volume (DV_0.1), viscosity, density and surface tension. Assays were performed in triplicate, using Teejet XR8003 flat fan nozzles at 200 kPa (medium size droplets). Spray solutions were stained with Brilliant Blue Dye at 0.6% (m/ v). DMV, V100, viscosity cause most influence on drift hazardous. Adjuvant characteristics and respective methods of evaluation have applicability in drift risk by agricultural spray adjuvants.

Efficiency of weed control can be increased if the herbicide formulation provides higher target coverage and evaporation time that enable an adequate distribution of herbicide on the target plant, allowing the absorption to continue even after the droplets evaporation. The aim of this research was to assess the influence of glyphosate formulations on the wetted area and evaporation time of droplets on different targets. Tests were conducted with droplets sizing from 500 μm containing three formulations of glyphosate (isopropylamine salt, ammonium salt and potassium salt) deposited on three surfaces, two leaves (Bidens pilosa and Cenchrus echinatus) and glass slides. Sequential images analyses were used to quantify the evaporation time and the wetted area. An experimental system was utilized that was composed of a droplet generator, a stereo microscope with a camera to capture images, as well as an environmental chamber controlled for temperature and relative humidity. The kind of glyphosate formulations and target surfaces are crucial in the wetted area and evaporation time. The isopropylamine salt decreased the wetted area and evaporation time when compared with ammonium salt and potassium salt for all the surfaces deposited on. Bidens pilosa allows an increased wetted area for all the glyphosate formulations when compared to Cenchrus echinatus and glass slides.

Insecticide spray drift can lead to reduced control efficiency and loss of product to the environment. Thus, we conducted a study to evaluate the effect of different spray nozzles and the addition of adjuvants in insecticide spray on the resulting droplet spectrum and wind tunnel drift. All experiments were conducted in a completely randomized design with four repetitions using a 5 × 3 factorial scheme. Five spraying solutions were studied; one contained only water and the other four comprised thiamethoxam + lambda-cyhalothrin (no adjuvant, Oro-solve, Wetcit Gold, and Orobor N1), in combination with three spray nozzles (AXI, JFC, and J3D). The droplet spectrum was evaluated through the volumetric median diameter, relative amplitude, and percentage of the droplet volume with diameter ≤ 100 µm. The drifts were evaluated in a wind tunnel at 5, 10, and 15 m. Data were subjected to analysis of variance and means were compared using the Tukey’s test. In addition, a principal component analysis was performed. Application of the insecticide with the adjuvants combined with the different nozzles changed the droplet spectrum and the risk of drift. The AXI nozzle and the J3D associated with the Oro-solve and Wetcit Gold adjuvants resulted in a greater volumetric median diameter of the droplets and drifts were observed at 5 m.

On tomato, cucumber and bell pepper cultivation, commonly large quantities of plant-protection products are applied, to control pests and diseases, as a way to guarantee better productivity and final product quality. The knowledge of spreading and evaporation time of spray droplets is fundamental to understand the interaction between fungicides and target surface for proper distribution of this fungicide. This study was installed to determine the wetting area and droplet evaporation of sprays containing the fungicide Cabrio Top, with or without adjuvant Nimbus^®, deposited on leaves and artificial surfaces (glass slide). A system was used which analyzes images composed of a droplet generator, a stereoscope camera for capturing images and a climatic chamber for controlling temperature and relative air humidity. Droplets of 600 µm in diameter containing spray solution were deposited on leaf surfaces and on glass slide and sequential images were used to quantify the wetting area and the evaporation time. The spray solution and the target surface are determinant for wetness and droplet evaporation after deposition. Evaporation time and surface tension were inversely proportional to the wetting areas. Addition of adjuvant Nimbus^® (0.5%, v/v) reduced the surface tension and provided an increase in the wetting surface area, except on tomato leaves which had shown low wetting capacity in both fungicide solutions applied.

O objetivo deste trabalho foi comparar a metodologia convencional de amostragem de solo com a análise espacial para a recomendação de calagem e adubação de nitrogênio, fósforo e potássio em solo cultivado com café conilon. O experimento foi realizado nas safras de 2004/2005 e 2005/2006, em área de 1,0 ha, com as amostras retiradas na profundidade de 0-0,20 m. No método convencional, coletaram-se 15 subamostras em caminhamento ziguezague, constituindo uma amostra composta, e, no método espacial, construiu-se uma malha amostral de 109 pontos georreferenciados. Com os resultados das análises, foi calculada a necessidade de calagem e adubação em função do teor do elemento no solo e da produtividade esperada das plantas. Os dados foram analisados por meio da estatística clássica (descritiva e exploratória) e pela análise espacial, utilizando técnicas de geoestatística (modelagem da estrutura de variabilidade espacial e realização de inferências) e geoprocessamento (álgebra de mapas). Com exceção da recomendação de fósforo em 2005 e potássio em 2006, todas as demais recomendações apresentaram dependência espacial. A análise dos dados pelo método espacial possibilitou identificar zonas de déficit ou excesso de calagem e de adubação na área, que não poderiam ser definidas com o método convencional de amostragem (ziguezague).