• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.439-477
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• 2000

Seasonal variation in species composition of fishes in the eelgrass bed in Angel Bay of the southern coast of Korea was determined using monthly samples by a beam trawl from April 1998 to March 1999, A total of 39 species, 2,065 individuals and 8,930 g of fishes were collected during the study period. The fish were composed of the small-sized resident species and the juveniles of Leiognathus nuchalis, Pholis nebulosa, Spgnathus schlegeli and Sebastes ineinis predominated in abundance, accounting for $60{\%}$ of total number of individuals. The number of species and biomass were low from December to March when the water temperature was low, The biomass increased by the catch of a large number of L. nuchalis and S. inemis in April and May when the eelgrass grew fast. The fish numbers decreased in June and July when the adults of the resident species declined after the spawning. A large number of juveniles which had released in spring occurred in August. The biomass of fish decreased from September, and a few number of fish were collected in winter. Species were grouped into four by cluster analysis: the warm season group including P. nebulosa, S. schlegeli and L. nuchalis, the cold season group including Chaenogobius heptaoanthus and Platycephalus indieus, the group of fish species occurred during the growing season of eelgrass such as P. couoides, S. inermis and P. perooides, and the group of fish species occurred during decaying season of eelgrass such as S. cirrhifer and H. coronatus. Principal component analysis indicated that seasonal variation in species composition was determined by the water temperature and standing crops of eelgrass.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.161-170
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• 2020

There is systematic spatial variations in environmental properties due to sensitive reaction to external conditions at plastic greenhouse occupied 99.2% of domestic agricultural facilities. In order to construct 3 dimensional distribution of temperature, relative humidity, CO₂ and illuminance, measurement matrix as 3 by 3 by 5 in direction of width, height and length, respectively, dividing indoor space of greenhouse was designed and tested at experimental site. Linear regression analysis was conducted to evaluate optimal estimation method in terms with horizontal and vertical variations. Even though sole measurement point for temperature and relative humidity could be feasible to assess indoor condition, multiple measurement matrix is inevitably required to improve spatial precision at certain time domain such as period of sunrise and sunset. In case with CO₂, multiple measurement matrix could not successfully improve the spatial predictability during a whole experimental period. In case with illuminance, prediction performance was getting smaller after a time period of sunrise due to systematic interference such as indoor structure. Thus, multiple sensing methodology was proposed in direction of length at higher height than growing bed, which could compensate estimation error in spatial domain. Appropriate measurement matrix could be constructed considering the transition of stability in indoor environmental properties due to external variations. As a result, optimal measurement matrix should be carefully designed considering flexibility of construction relevant with the type of property, indoor structure, the purpose of crop and the period of growth. For an instance, partial cooling and heating system to save a consumption of energy supplement could be successfully accomplished by the deployment of multiple measurement matrix.

• Korean Journal of Weed Science
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• v.5 no.2
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• pp.202-210
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• 1985

Requirements in weed control in a mulberry field are much similar to those in orchards, but also feature a longer period of weed control of various kinds of persistent weeds, i.e., spring, summer, and winter annuals as well as perennials. In addition the mulberry tree is relatively more sensitive to herbicide injury. Hence, very few herbicides have been used in mulberry field. The present study was conducted to evaluate the usefulness of oxyfluorfen in comparison with alachlor and simazine, which are registered for ordinary mulberry field in Korea, for weed control efficacy in the new, rapidly increasing practice of transparent polyethylene-film mulched and densely planted younger mulberry culture. Dominant spring weeds were Galium spp., Erigeron spp., Polygonum senticosum, and Chenopodium spp. in the non-mulched interbed area in contrast to the Digitaria spp. and Potulaca spp, under mulch. Dominant summer weeds were Digitaria spp., Portulaca spp., Erigeron spp., Artemisia spp. and Calystegia japonica in the non-mulched interbed area while weeds did not occur significantly during summer under mulch which were shaded by vigorously growing mulberry trees. The weeds occurred under mulch in spring reduced shoot growth of young mulberry tree resulting in the reduced yield of mulberry leaves for silkworms. The weeds occurred in the interbed area did not affect until May, but interfered later summer- and fall-growth of mulberry tree. Early single spring application of alachlor(EC), simazine(WP) or oxyfluorfen(EC) at a rate of 650 g, 750 g or 350 g ai per ha, respectively, controlled most annuals satisfactorily to fall in the mulched bed area. In the nonmulched interbed area, however, thrice does of alchlor or simazine was necessary for satisfactory control of spring weeds, followed by summer application of alachlor or simazine at twice dose level as tank mixture with paraquat at 490 g ai per ha for satisfactory control of summer to fall weeds. Single spring application of oxyfluorfen at a rate of 1400 g ai per ha was persistently effective to control satisfactorily even summer and fall weeds. However, heavy rainfall splashed soil borne oxyfluorfen to the lower branch leaves causing some leaf burns. Spring application of oxyfluorfen at a rate of 350 g ai per ha followed by summer application of oxyfluorfen and paraquat tank mixture (350 g ai + 490 g ai) was the best choice for the non-mulched interbed area weed control among the treatments.