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Water is a crucial resource to produce dairy milk and studies are required to identify opportunities for improvements in water management. This study evaluates the water productivity of milk (WPMilk) produced on 67 farms located in southern Brazil and the influence of dairy cattle production systems (pasture-based, 57 farms; semi-confined, 7 farms; confinement, 3 farms) on water productivity. Indirect and direct water flows were taken into account and the dairy milk was the output. Pasture yield was estimated based on a weighted average. Indirect water represented >98 % of water consumption for milk production on farms assessed. In the pasture-based system, the WPMilk ranged from 0.27 to 1.46 kg FPCM (Fat Protein Corrected Milk) m-3 of water; in the semi-confined system it ranged from 0.59 to 1.1 kg FPCM m-3; in the confined system, it ranged from 0.89 to 1.09 kg FPCM m-3. Results show that 20 farms in the pasture-based system presented higher WPMilk than the maximum WPMilk of farms in the semi-confined system. Comparing outcomes of farms in the confined system with pasture-based system, similar results were observed with higher WPMilk on 22 farms in the pasture-based system. Results indicate that, regardless of the type of production system, water productivity is influenced by the dairy productivity indicators of the farm, such as milk yield and feed components. The large variability in the WPMilk was expected and reflects the inherent attributes and conditions affecting this indicator, which underlines the importance of assessing it on a farm scale. Consequently, achieving high dairy productivity indicators should be encouraged in the pasture-based system due to the environmental, economic and social advantages for the farmer. Results advance the knowledge about water flows and WPMilk in different dairy cattle production systems besides defining the first benchmarks for WPMilk produced on farms in Brazil.
The study and knowledge of the depuration capacity of the water resources, is necessary to preserve them. This study was objective identify the attenuation capacity of the Belo stream - Caxias do Sul - RS / Brazil, through the evaluation of physicochemical parameters, distance and slope between 4 points located along the stream. Were collected five samplings, bimonthly. The data were analyzed through descriptive statistics, one-way Analysis of Variance (ANOVA "one way"), Tukey’s test e Pearson’s correlation. The results showed that there is an improvement in the quality of water resources from upstream to downstream of the stream. However, despite the stream have a high attenuation potential, is necessary the development of control actions to input of industrial and domestic effluents, to prevent the ecological impairment of the same. http://dx.doi.org/10.18226/23185279.v3iss1p1
26 May 2014 in WIT Transactions on Ecology and the Environment
Os fatores naturais e, em especial os antrópicos, que contribuem para a variação espacial e temporal da qualidade da água superficial nas bacias hidrográficas do município de Caxias do Sul foram determinados com uso de técnicas multivariadas de análise de dados. Foi utilizada a técnica de Análise do Componente Principal (ACP) como base para o estudo. O monitoramento foi realizado em 30 pontos de monitoramento no período compreendido entre setembro de 2012 a janeiro de 2014. A amostragem foi realizada bimestralmente, abrangendo seis bacias hidrográficas, onde foram analisados 21 parâmetros físicos, químicos e biológicos. Os resultados obtidos demonstraram que com o emprego da ACP, foi possível explicar uma variância total de 71,3% para os dados de qualidade de água. Ainda, constatou-se que os principais fatores que contribuem para a variação da qualidade da água nas bacias hidrográficas da região são a poluição doméstica e industrial, sobretudo do setor galvonotécnico. Foi verificada por fim, uma tendência à atenuação dos poluentes nos corpos hídricos à jusante das áreas urbanas e de grande influência antrópica, especialmente na medida em que há menor pressão das áreas urbanizadas sobre as bacias que drenam a região.