|Rotz, Clarence - Al|
Submitted to: International Grasslands Congress
Publication Type: Proceedings
Publication Acceptance Date: 2/14/2005
Publication Date: 7/1/2005
Citation: Rotz, C.A., Sanderson, M.A., Wachendorm, M., Taube, F. 2005. Evaluating the economic and environmental sustainability of integrated farming systems. International Grasslands Congress. 20:378. Interpretive Summary: An interpretive summary is not required.
Technical Abstract: Economic and environmental sustainability has become a major concern for forage-based animal production in Europe, North America and some other parts of the world. Development of more sustainable farming systems requires an assimilation of experimental and modelling research. Field research is critical for supporting the development and evaluation of models, and modelling is needed to integrate farm components for predicting the long-term effects and interactions resulting from farm management changes. As an example, field experiments conducted on the sandy soils of northern Germany have determined nitrogen fluxes in grass and maize silage production systems. Treatments that included various levels of fertilizer and manure applications were monitored for nitrate leaching and gaseous losses of nitrogen. These production systems and treatments were simulated using a whole farm model for a typical dairy farm in northern Germany, with and without the use of rotational grazing. Farm profit increased with the use of either maize silage or grazing. Nitrogen losses increased with the use of grazing but decreased with the use of maize silage. An appropriate combination of grass, maize silage and grazing was used to maximize farm profit with little or no increase in nitrogen losses. Although these results are not directly transferable to other sites, through the use of the model, these and other management practices are being evaluated in other regions of the world. Farm and watershed scale models are also being linked to predict the effects of farm management on the surrounding region and beyond. When properly supported with field observations, whole-farm simulation provides an effective research and teaching tool for integrating farm processes and predicting farm performance, profitability and environmental impact. This tool is very useful for developing, evaluating and transferring more sustainable grassland systems to commercial livestock production.