Comparing the environmental impacts of pasture-based and confinement-based dairy systems in Nova Scotia (Canada) using life cycle assessment

A life cycle assessment (LCA) of dairy systems in Nova Scotia was conducted to compare environmental impacts of typical pasture and confinement operations. Data on material and energy inputs and outputs of these systems were obtained from local researchers and industry, and life cycle impacts in 11 categories were quantified. Use of concentrate feeds, N fertilizers, transport fuels and electricity were dominant contributors to environmental impacts. Somewhat surprisingly, grazing cows for five months per year (typical of pasture systems in Nova Scotia) had little effect on overall environmental impact. Scenario modelling suggests, however, that prolonged grazing is potentially beneficial. Compared with total confinement, a seven-month grazing scenario performed better in seven of the environmental impact categories evaluated with greatest potential improvements associated with acidification potential, ozone depletion potential, human toxicity and fresh water ecotoxicity. In contrast, land use was the only category in which an increased reliance on pasture is predicted to result in a marked increase in environmental impact.     

The identification and assessment of ecological risks for land consolidation based on the anticipation of ecosystem stabilization: A case study in Hubei Province,China

The purpose of this study is to identify and classify the ecological risks in land consolidation, and to develop a framework of the theory and method to assess the change of ecological risk degree before and after land consolidation. Environmental impacts and ecological risks of land consolidation have recently drawn much attention, and there are two opposing viewpoints to assess these impacts and risks in the academia of China. Both viewpoints result from the bias of assessment anticipation. Land consolidation includes four main engineering aspects in China, and ecological succession from start of land consolidation to ecosystem stabilization should pass three phases. Different ecological impacts and risks of land consolidation rise from different phases of ecological successions. According to the climax theory of ecology, we developed a framework of the ecological risk assessment based on the anticipation of ecosystem stabilization (ERABAES) for land consolidation. We applied analytical hierarchical processing (AHP) method to the data resources from the land consolidation project in Southern China to allocate weightings to the indices of ecological risk (ER), and to set up an integrated index system for the ecological risk identification. This integrated index system encompasses the ecological risks with three factors (water, soil and biology) and 14 indices. The results of the project show: (1) The ER is reduced from 58.02 to 28.8 after land consolidation and the degree of ecological risk is down from Degree III to Degree IV. (2) According to the element analysis, the water ER is reduced from 21.53 to 6.16, its contribution to reduce the ecological risk is 53%; the reduced ERs of soil and biology are respectively 12.79 and 1.06, their contribution of ecological risk reduce is lower than water.