Emergy methodology was used to analyze the biophysical basis of Korean agriculture and assess its sustainablility. Total yearly emergy input into Korean agriculture was 7.72×10²² sej/yr in 2013. Purchased inputs were the dominant emergy source, accounting for 90.1% (6.95×10²² sej/yr) of the annual input. This clearly indicates that the Korean agriculture is a modern, industrialized system that depends mostly on market goods and services derived from nonrenewable resources. The monetary equivalent of the total emergy input was 18.9 trillion ₩/yr, 1.5 times greater than the total production cost from farm expense surveys. Emergy return on investment of Korean agriculture was low, with an emergy yield ratio of 1.11. Korean agriculture appears to exert pressure on the environment as revealed by the high environmental loading ratio of 9.30. With very low emergy input from renewable sources (9.7%) and high environmental pressure, Korean agriculture is not sustainable, with an emergy sustainability index of 0.12. This study suggests that higher use efficiency of and lower dependence on nonrenewable purchased inputs need to be prioritized in an effort to enhance the sustainability of Korean agriculture.

Access to clean and affordable water is one of the fundamental human rights because water is essential to life and a foundation for socioeconomic development of any country in the world. Despite the efforts to secure water supply in Burundi, the amount of water supplied by public utilities does not meet the demand of the population because population keeps increasing with fluctuation of weather conditions. This study selected north Bujumbura that is a sprawling new residential area in the western part of Burundi as a case to investigate the potential of rainwater harvesting in meeting water demand of the country. Based on a long-term average monthly precipitation in the region, the rainwater harvesting potential was assessed as a function of roof sizes, number of households, and runoff coefficients of roof materials. For the entire region of north Bujumbura, the current water supply capacity of the local water company combined with the rainwater harvesting potential resulted in the water surplus of 468,604.1 m3/yr. Although three communes among them still showed water deficit in dry season, they still got help from rainwater to relieve their water shortage. This suggests that at the regional scale, proper storages and water quality control for harvestable rainwater could contribute to relieving the regional water shortage and allow the population growth.

Solid wastes are among the most pressing environmental and resource concerns in Korea. The Korean government has been implementing various management alternatives to reduce the production of solid wastes and recover valuable resources from them. Refuse-derived fuel (RDF) manufacturing facilities are one of projects that aim at recovering energy from solid wastes. This study used the emergy evaluation procedure to assess the feasibility of an RDF manufacturing facility in Wonju, Korea. By converting 10,442.6 tons of combustible solid wastes into 5,801 tons of solid fuel in 2007, this facility prevented the loss of useful resources with an emergy quantity of 3.70 × 1019 sej/yr. This amounted to a potential worth of 7.04 billion emW/yr. Total emergy input required to produce 5,801 tons of RDF was 5.91 × 1019 sej/ yr with an emvalue of 11.3 billion emW/yr. The Wonju RDF manufacturing facility contributed more to the Korean economy beyond its investment cost as revealed by the emergy yield ratio of 2.67. Direct emergy benefits and costs of the RDF facility were calculated as 1.20 × 1010 emW/yr and 3.31 × 109 emW/yr, respectively, resulting in the net emergy benefit/cost ratio of 2.62. This indicates that the RDF facility was a feasible option for managing solid wastes for the city of Wonju in Korea. This study demonstrated the usefulness of the emergy concept and methodology in evaluating management alternatives for solid wastes in Korea.

Aquatic and riparian vegetation of river ecosystems are very important both in ecological and management perspectives. Vegetation surveys were conducted to understand the characteristics of riparian vegetation in the mid and lower reaches of the Nakdong River, Korea. A total of 68 families and 260 species were identified at eleven survey sites. The numbers of taxa were similar to those reported in a previous survey in 1996,but the percentage of naturalized plants increased more than two times compared to that in the previous survey. Survey sites near Yangsan Bridge and Nambu Park in Yangsan showed the highest percentage of naturalized plant species. Urbanization indices of the survey sites were high at 18.8% on average. Therophytes were the most dominant plant life form at the survey sites with 39.2% of total plants identified, followed by phanerophytes (19.2%), hemicryptophytes (18.9%), aquatic plants (13.9%), cryptophytes (5.8%), and chamaephytes (3.1%). The relative composition of hemicryptophytes decreased whereas those of therophytes and chamaephytes increased compared to those in the survey in 1996. This may be due to increase in dryness of riparian soils or degradation of riparian areas. Plant compositions at sites near Jeokpo Bridge and Hwoicheon suggest that the composition and distribution of riparian vegetation are affected by land use pattern surrounding riparian areas or human accessibility to the areas.