The aim of this investigation was to evaluate the efficiency of partial treatment of animals infested with horn flies. Forty-five Guzerat cows between 4 and 7 years of age were divided into three groups (15 cows per group). The treatments were as follows: in groups G33 and G100, 33.3 and 100% of the cows were treated with one insecticide-impregnated ear tag/animal (40% diazinon), respectively, while in the group GC, the cows were not treated (control). The flies on the cervico-dorsal-lumbar region of the cows, in all three groups, were counted every 14 days. The experiment lasted from September 2006 to September 2009. Over this period, six four-month ear tag treatments, with intervals of one to two months, were conducted on both treated groups. The animals of group G33 had a higher infection than those of group G100, and the number of flies ranged from 12 to 27 (group G33) and from 3 to 11 (group G100). However, groups G33 and G100 had lower infection levels than group GC, which presented from 45 to 87 flies. Partial treatment of cattle infested with horn flies using 40% diazinon insecticide is an efficient alternative for controlling this ectoparasite.
The lack of studies on spatial variability in integrated crop–livestock systems (ICLS) hinders understanding how to increase their efficiency by implementing precision agriculture (PA) practices. As such, little is known about how grain and forage crops interact and how to improve the decision‐making process on fertilization and forage management. One technique that can help manage such systems is the delineation of management zones (MZs), regions with similar yield potential and soil and topography characteristics. Thus, this paper assesses the spatial correlation between yield and potential factors affecting it, and identifies whether it is possible to establish MZs for field management of grain and forage crops in succession in ICLS. Bivariate Moran's index was used to identify the attributes most spatially correlated with the yields. Elevation, soil apparent electrical conductivity, and clay content were the most spatially correlated variables with soybean [Glycine max (L.) Merr.] yield, while soil organic matter content and elevation were the most spatially correlated with the forage yield. Spatial principal components analysis and fuzzy c‐means clustering algorithm were combined to delineate MZs for each crop. The MZs created for soybean were statistically different in grain yield, available phosphorus (P) in the 0‐to‐0.40‐m layer and pH in the 0‐to‐0.20‐m layer. The forage MZs showed significant differences in terms of available P in the 0‐to‐0.40‐m layer. We conclude that MZs for ICLS tends to be crop specific, demanding different MZs to characterize soybean and forage spatial variability.
Resumo O objetivo do trabalho é verificar se há relação entre biomassa e autura de Brachiaria decumbens, Brachiaria brizanta, Sorgo e Feijão com leituras de um sensor de reflectância do dossel das plantas. Para isso foi conduzido um experimento na Faculdade de Engenharia Agrícola da UNICAMP. Verificou-se baixa relação entre as medidas do sensor e os parâmetros biométricos avaliados das plantas.
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