The objectives of this study were to evaluate and compare the environmental impacts and feed costs of two beef-fattening experiments using linseed oil soap fatty acids (LS) by the life cycle assessment (LCA) method. Crossbred heifers between Japanese Black sires and Holstein dams were used for two fattening experiments. In the first experiment, three treatments were compared; total mixed rations (TMR) were supplied from 19 to 27 months of age (Control; C1 group), 2.9% LS on TMR from 19 to 27 months of age (L1 group), and 2.9% LS on TMR from 18 to 27 months of age (L1e group). In the second experiment, all heifers were fed from 19 to 27 months of age and the three treatments were designed; Conventional TMR (C2 group), 2.7% LS on TMR (L2 group), and 2.7% linseed and rape seed oil soap (LRS) on TMR (LR2 group). The amounts of emitted pollutants and energy consumption from fossil fuel combustion and volatilization inside the system boundary (including feed preparation, feed transportation, barn, animal, and composting) were calculated based on data from each group. Environmental impacts of global warming, acidification, eutrophication, and energy consumption were estimated. The functional unit was 1.0 kg of average daily gain. The results showed that contributions to environmental impacts of global warming, acidification, and eutrophication in LS or LRS groups were smaller than non-supplemented groups (Control). This was due to the effects of methane mitigation and reduction of amounts of feed consumption caused by LS or LRS supplementation. Environmental impacts of the L1e group were smaller than the L1 group in all impact categories. In general, there was the trade-off between feed costs and mitigation effects of environmental impacts, and the LR2 group showed the lowest increase in feed costs and the highest reduction of environmental impacts in this study.
Djarai ethnolinguistic groups, who live in Ratanakiri Province of Cambodia, engage in the traditional practice of swidden cultivation. However, recent economic developments, such as the shifts toward large-scale plantations and cash crop production at the household level, have affected those swidden cultivators. In order to discuss the sustainability and adequacy of such new developments, it is important to clarify the traditional practice of swidden cultivation. This study examines traditional practices, farming activities, and land-use patterns related to Djarai swidden cultivation. It utilizes remote sensing and qualitative research methods and applies supervised classification and visual image analysis to ALOS AVNIR-2 and Worldview-1 data. The study also uses qualitative methods to collect and analyze in-situ information. Remote sensing and ground truthing techniques prove that Djarai swidden cultivation is interwoven with cash crop production. At the same time, qualitative methods reveal that Djarai swidden cultivation is a multiple cropping system that works in close relation with their traditional belief and land tenure practice. These traditional farming systems have been transformed due to development activities undertaken in the province, which have led Djarai villagers to change not only their farming system, but also the social system of their village.