ABSTRACT The wear rate of spray nozzles affects several factors. This study aimed to investigate the influence of spray nozzle wear rate on droplet characteristics, such as droplet size, droplet homogeneity, droplets prone to drift, and flow rate variation. Eight hydraulic nozzles models (AIXR-110-02, JSF-110-02, TT-110-02, DG-110-02, XR-110-02, ADI-110-02, XR-110-02, and AI-110-02) were subject to an accelerated wear test, and their effects were measured at six experimental wear times (0, 10, 20, 30, 40, and 50 hours). The following variables were evaluated: volume median diameter, percentage of spray volume containing droplets smaller than 100 μm (prone to spray drift), flow rate (L min-1), and relative span, which indicates droplet size homogeneity. The droplet population was measured using a laser particle size analyzer. The use of the spray nozzle tip influences the quality of the spray application due to the wear rate. This study revealed a linear increase in the flow rate and volume median diameter as functions of the wear rate increment. The droplet size increased over the wear time, which consequently modified the volume percentage of droplets smaller than 100 μm and significantly increased the relative span.

Foi realizado experimento visando estudar os efeitos da irrigação suplementar e da adubação nitrogenada na produtividade de aveia (Avena sativa L.), variedade UPF7, para ferragem. O delineamento experimental foi o de blocos ao acaso com parcelas subdivididas, com quatro repetições. Os tratamentos constaram da combinação de quatro lâminas de irrigação aplicadas quando a evaporação acumulada no tanque "Classe A" (ECA) atingia aproximadamente 30 mm (I = 0%, I = 50%, I = 100% e I = 150% de ECA) e quatro níveis de adubação nitrogenada (N = O, N = 80, N = 160 e N = 240 kg.ha-1 de nitrogênio). A máxima produtividade total de matéria seca (6,9 Lha-1) foi estimada para 319,2 mm de água e 152,4 kg.ha-1 de nitrogênio. Aos preços considerados para insumos e produto, a máxima receita líquida (R$ 897.ha-1) foi obtida para 310 mm de água e 120 kg.ha-1 de nitrogênio.

This study was conducted to determine the effects of supplemental irrigation and nitrogen fertilization on forage oat (Avena sativa, L.) productivity, variety UPF7. The experiment was a split-plot randomized block design with four replications. The experimental unit consisted of combinations of four irrigation depths applied when cumulative Classe A pan evaporation (ECA) approximately reached 30 mm, (I = 0%, I = 50%, I = 100% and I = 150% of ECA), and four nitrogen levels (N = O, N = 80, N = 160 e N = 240 kg.ha-1). The total maximum productivity of dry matter (6,9 t.ha-1) was obtained for the water depth of 319,2 mm and 152,4 kg.ha-1 of nitrogen. For the considered prices, the water and nitrogen levels that induced the maximum net income were 310 mm and 120 kg.ha-1, respectively, reaching a maximum net return of R$ 897.ha-1.