著者

Haruki Takayanagi Takayoshi Nishida

出版者

生態工学会

雑誌

Eco-Engineering (ISSN:13470485)

巻号頁・発行日

vol.29, no.2, pp.53-56, 2017-04-30 (Released:2017-04-30)

参考文献数

9

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In recent years, an increasing emphasis on conserving biodiversity in cultivated land has led to a need for environmentally friendly and sustainable agriculture that does not depend on the excessive use of agrochemicals. However, it can be difficult to generate high crop yields without using herbicides because alternative methods of restricting weed growth are often costly and labor-intensive. Here, we designed a mesocosm to examine the weeding efficacy of a cheap, commercially available, automatic robot ball, which was originally designed for house cleaning. The weeding robot performed very well, particularly for sprouts of Monochoria vaginalis var. plantaginea, a major paddy weed found in central Japan.

著者

増田 篤稔 隠地 武彦 村上 克介

出版者

生態工学会

雑誌

Eco-Engineering (ISSN:13470485)

巻号頁・発行日

vol.27, no.3, pp.67-72, 2015-07-01 (Released:2015-08-26)

参考文献数

7

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Controlling dissolved oxygen (DO) level in rearing tank is one of the most important for intermediate breeding of abalones with land based production facilities. Continuous DO measurement was conducted for two rearing tanks of 15.5 m3 seawater each and containing 19,000 abalone of 50 mm length and 60,000 abalone of 23 mm length in running seawater condition of 17.6 m3 per hour. Oxygen consumption of abalone was also examined. A model formula expressing oxygen distribution in rearing tank was made based on these data. There are diurnal changes in DO concentration in rearing tank, higher in afternoon and lower in midnight, and DO decreased to less than 80% of saturation couple of times, harmful level for good growth.

著者

Viet Han Duc 堀田 健治 岡本 強一

出版者

The Society of Eco-Engineering

雑誌

Eco-Engineering (ISSN:13470485)

巻号頁・発行日

vol.16, no.1, pp.45-52, 2004

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Mekong Delta is a big rice production area and an important place in the socio-economic development of Vietnam. Especially, Dong Thap Muoi (DTM) shares large production area in Mekong delta. Although the floods happen every year, the people still live there. At present, in order to reduce flood damage, the Government proposes projects to build Flood Safety Zones (FSZ) in this area and in fact, some of them have already been constructed. However, there are many people who do not wish to relocate to these zones.<br>In order to define the above, a questionnaire survey on resident migration during floods, resident's attitudes about moving to FSZ was conducted. The survey indicated that the most of all households need to find a place to evacuate. The "main road" and "peoples' house" are the most common responses to the location of evacuation. It was found that 1 km to 5 km appear to be the maximum desirable distance to the field. Every year, resident spends over 1/5 of annual income for house repair. Environmental problems caused by water, such as skin disease, sanitary, drinking water supply during flood were also revieled.<br>Finally, based on the obtained results, points of consideration to the planning of FSZ were discussed.