• Asian-Australasian Journal of Animal Sciences
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• 제17권7호
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• pp.1026-1032
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• 2004

In this study, we assess the recent changes in the amount of excretion by the livestock industry, and discuss the effects of increasing the ratio of cultivated land on the reduction of surplus nitrogen from a cost-performance perspective. Nitrogen has contributed to acidification of ecosystems and nitrate concentrations in groundwater, especially in Europe. Therefore, we assessed the level of nitrogen waste from the domestic Japanese livestock industry, including cattle, swine and poultry during the period 1987-2001. This assessment assumed that 40% of the nitrogen from the domestic livestock industry was emitted as gas into the air and that 60% of the nitrogen was contained in manure used on domestic cultivated land. Nitrogen excreted from livestock, excluding gas emission, decreased by 11% from 0.504 million tons to 0.447 million tons during 1993-2001. Thus, the peak period of nitrogen excretion from livestock is already past in Japan. However, the area of cultivated land under management also decreased during 1990-2000. In addition, the area of paddy and upland fields left unplanted for a year increased during 1990-2000. Therefore, if all manure from the domestic livestock industry had been utilized on the fields as organic fertilizer, but not on arable land left uncultivated for the past year, the nitrogen per net area of cultivated land would have increased by 5%, from 125 to 131 N kg/ha, during 1990-2000. To reduce the nitrogen ratio on cultivated land through the planting of feed grain to utilize the nitrogen, a comparison of the cost performance of feed grains indicated that barley would be more suitable than wheat, rice or soybean. Had barley been planted in 100% of the land left fallow for the past year in 2000, 4% (20,000 tons) of the nitrogen from livestock waste would have been used in the harvest, and the nitrogen per land unit would have not increased but decreased from 125 to 121 N kg/ha during the same decade. Furthermore, when converted into Total Digestible Nutrients, 7% of imported feed corn could have been replaced with the harvested barley in 2000. Planting barley on this fallow land had three benefits; reducing the risk of manure overload on the land, slowing down the decrease in cultivated land, and raising the feed self-sufficiency ratio. Thus, it would be beneficial to plant feed grain such as barley in land left fallow for the past year through utilization of manure.

• Asian-Australasian Journal of Animal Sciences
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• 제18권7호
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• pp.1022-1028
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• 2005

The objectives of this study were to evaluate and compare the environmental load of two different concentrate feed supply systems to the Japanese domestic livestock industry using the Life-cycle Assessment (LCA) method. The current system was defined as that requiring 11.469 million tons of corn imported from the US by sea transport and supplied as concentrate feed to the Japanese domestic livestock industry. The new system proposed by Kaku et al. in 2004 was defined as where 802,830 tons of US imported corn would not be planted in US and would be replaced by barley planted in 278 thousand ha of Japanese domestic land left fallow for the past year. In this case, 909,000 tons of domestic harvest barley would have been supplied as concentrate feed to the Japanese domestic livestock industry in 2000. The activities taken into account within the two system boundaries were three stages: concentrate feed production, feed transportation and gas emission from the soil by chemical fertilizer. Finished compost was regarded as organic fertilizer and was put instead of chemical fertilizers within the system boundary. Adoption of this new concentrate feed supply system by the Japanese domestic livestock industry could reduce 78,462 tons $CO_2$-equivalents of global warming potential, 347 tons $SO_2$-equivalents of acidification potential, 54 tons $PO_4$-equivalents of eutrophication potential and 0.842 million GJ as energy consumption below 2,000 levels. This LCA study comparing two Japanese domestic livestock concentrate feed supply systems showed that the stage of feed transport contributed most to global warming and the stage of emission from the soil contributed most to acidification and eutrophication. The Japanese domestic livestock industry could participate in emissions trading with $CO_2$-equivalents reduced by shifting from some imported US corn as a concentrate feed to domestic barley planted in land left fallow. In that case the Japanese government could launch emissions trading in accordance with Kyoto Protocol in the future.