The purpose of this paper is to present a long-term sustainable nutrient material cycle which ease the depletion problems of phosphorus resources. Countermeasures have already been proposed as 1) recycling of livestock wastes and sewage sludge, and 2) welling up the deep-sea water and extraction of phosphorus resources out of the water. However, they are not satisfying. The scheme of on-site nutrient recycle in plant-factories using the hydroponics or artificial cultural medium can solve the depletion problems of phosphorus resources without losing the nutrients material balance between ocean and land. This scheme is regarded to present a long-term sustainable nutrient material cycle.

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We studied the soil carbon budget in a peach orchard in the Kofu basin, central Japan, from September 1999 to August 2000. Soil respiration rate (Rs) was measured monthly using the dynamic closed chamber method and annual carbon emission from the soil was estimated using the exponential relationship between the soil surface temperature and the measured Rs. The amounts of litter from peach trees and floor vegetations, applied fertilizer and manure, and paper bags for fruits that fell on the ground were estimated to evaluate carbon supply to the soil. The total carbon emission and the heterotrophic carbon emission were estimated to be 1065 g Cm^-2y^-1 and 565g Cm^-2y^-1, respectively. The total carbon supply was 1136 g Cm^-2y^-1 (litter from floor vegetation 56 %; fertilizer and paper bags 23 %; and litter from peach tree 21 %). It was characterized that carbon from floor vegetation is the largest input to the soil in the orchard. The soil carbon budget in the orchard was positive (571 g Cm^-2y^-1);hence, it is suggested that the soil acts as a carbon sink. We determined three types of soil carbon budget in agro-ecosystems: negatively balanced in upland crop fields as source ecosystem for carbon, nearly balanced or equilibrated in paddy fields and mulberry fields, and positively balanced in orchards as a sink ecosystem for carbon .

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In the Tone basin of Gunma Prefecture, phosphorus loads generated from different sources such as man, animal, farmland and industrial wastewater were estimated using a load factor, and the way to diminish the phosphorus load was investigated taking a potential phosphate crisis into consideration. The result showed that animal waste was the major source of phosphorus load in the basin . About 60 % of the total phosphorus load come from animal waste; approximately 30 % from industrial wastewater. The high phosphorus load zones appeared in the middle basin, due to a herding of animal. In addition, run-off ratio calculated from the phosphorus loads generated from all the sources and discharged into Tone River was about 3.8 % and was smaller than that of nitrogen. This result suggested the difference between behaviors of phosphorus and nitrogen in the basin. It was considered that phosphorus loads generated from the sources accumulated in the basin. Based on the results, the way to reduce the phosphorus load was examined. Considering the crisis of phosphate mainly used as fertilizers, recycling of animal waste to farmland could be a good way to diminish the load. However, there is a limit in the recycling of animal waste because of the decreasing tendency of farmland area in the basin . Accordingly, utilization of animal waste as energy source was proposed as other measures, and electric power to be produced from the remainder of animal waste was also estimated. The calculated result showed that the output of 460, 000 kWh/d could be produced in the case of using a process consisting of anaerobic digestion and gas-engine. It was reconfirmed that animal waste could be used as fertilizer and utilized for producing electric power .

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Experiments for liquid-waste treatment have been carried out using the cavitation type liquid-waste treatment system by ozone for the kitchen liquid waste at a restaurant industry. As a result, when bath type system was used, n-Hexane, BOD and SS have been able to be reduced by 85 %, 49 % and 85 % respectively. Using the existing treatment establishment, the rate of decomposition for Oil component by this system by ozone is higher in comparison with the biological treatment system by MM-organisms. The weight of scum being produced as by-products in this system was about 10 % of the weight being produced by the biological treatment system. Therefore, it has been shown that this system is effective in the decomposition of waste sludge.

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In China, riverine ecosystems have been rapidly deteriorating for many years. In this study, the authors consider the Japanese model of overcoming public environmental problems and its potential application in China. The authors found resident awareness of river preservation along the Kamo River in Kyoto, Japan was much higher than among residents along the Funan River in Chengdu, China. The Chinese residents did not fully understand their role in river preservation, yet expected improvements by the government, particularly the national government, which has greater awareness of environmental problems and greater power to fix them than the local governments. In order to achieve real success in preservation of the urban river environment in China, the cooperation and coordination between NGOs and government must rapidly be improved. In Japan, NGO activities are well coordinated with the government while in China NGOs are few in number, strongly controlled by the government, and lack fundamental ideological support. NGOs in Japan and China share the problem of lacking experienced leaders for activities such as raising funds necessary for continuing and enlarging the groups' activities. The authors conclude that resident participation is an essential prerequisite for preserving urban rivers.

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With the aggravation of wetland destruction in China, more and more attention is being paid to the tension of wetland preservation, and the trend toward wetland preservation has been rising gradually. In this paper, the conditions of Chinese wetlands will be briefly introduced first, and after that I will report on the movement to preserve wetlands in China. The report will concentrate on the following points: joining the Ramsar Convention, the enactment of laws and policies to preserve wetlands, and the rise of concern surrounding wetland preservation.

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