• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.86-91
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• 1995

This experiment was conducted to understand the response on sowing rates at furrow sowing of rice in paddy field. As sowing rates was increased, the number of seedling stand per$m^2$ was icreased, while panicie number per plant was decreased slightly. Leaf area at heading stage and effective tiller ratio were decreased with increasing of sowing rates, but heading date was not defferent among sowing rates. According to sowing rates was increased, culm length, panicle length, breaking strength, culm diameter were decreased, while lodging index was increased. Also, field lodging was observed in the higer sowing rates over 5kg/l0a. Althougth the panicle number per $m^2$ was increased with increasing of sowing rates, spike let per panicle and percent of filled spikelet were decreased. According to the result from the path coefficient analysis, percent of filled spikelets well identified to be the most influential variables on the variability in rice yield, so that improving percent of filled spikelets by inhibition of field lodging was the important matter to increase the yield. The optimal sowing rate and the number of seedling stand were estimated to be 4.5kg/l0a and 105 per $m^2$ respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.215-220
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• 1985

This experiment was conducted to find out the effects of organic materials application on the growth of peanut, yield and chemical properties in mature field and newly reclaimed upland soil. The result can be summarized as follow. 1. Application of rice straw and rice hull increased the yield of peanut in mature field and compost plot was more yield than any other plot in newly reclaimed upland soil. 2. Rice straw and rice hull plot was heavier the weight of needles per plant than compost plot in newly reclaimed soil. 3. There was high correlation between soil O.M. at flowering stage and yield in newly reclaimed upland soil but was not significant in mature field. 4. Contents of soil O.M. did not change in mature field however this was increased tendency in newly reclaimed upland soil.

• The Korean Journal of Mycology
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• v.5 no.1
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• pp.33-37
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• 1977

This study was made in order to determine which Gibberella species were occurring on rice stems and seeds in the field, and their survival 5 months after harvest time. An average 12% of plants infected with 'Bakanae' disease occurred in 4 fields planted with non-treated seed. Prior to harvest, more perithecia of Gibberella moniliformis occurred on infected rice stems than of Gibberella rosea. But Gibberella rosea was most common on the seed, and perithecia of this species also survived best until spring. F. moniliforme, F. roseum and Ophiobolus sp. were isolated from seedlings planted from naturally infected seed at the rates of 10, 25 and 8% respectively and from infected stems at rates of 3, 10 and 2% respectively. Perithecia of Gibberella rosea survived through the winter on naturally infected rice stems when kept dry indoors, buried in field soil, or places in straw stackes in the field. They did not survive on straw left on the soil surface during the very cold and dry conditions of the 1976-'77 winter.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.319-325
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• 2010

The purpose of this study is to investigate the soil compositions, methane production, the number of methanogens, and the community structure of methanogens in rice paddy soils and dry field farming soils in the summer and autumn seasons. As a result of the analysis of soil compositions, any regular tendency to increase or decrease has not been found in most soil samples due to the change of seasons. It has also been found that more methanogens exist in the rice paddy soil that utilize organic farming practices and emptiness farming practices than in the dry field farming soil. The fewer numbers of methanogens utilizing the acetate have been found than those of the methanogens utilizing the hydrogen or the formate. In an experiment of methane production, the methanes increased for two weeks when the acetate was added, but they continued to increase for seven weeks more when the formate and the hydrogen were added. In the phylogenetic analysis using the mcrA gene, the methanogens had diverse clusters in the rice paddy soil, whereas the methanogens were concentrated only in a few clusters in the dry field farming soil.

• Korean Journal Plant Pathology
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• v.2 no.2
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• pp.69-81
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• 1986

Thirty two rice cultivars which have been cultivated or used as breeding materials in Korea were tested for screening rice cultivars resistant to leaf blast at adult-plant stages in the blast nursery hill plots. When compared on the basis of disease severities in individual leaves at different growth stages of rice plants under natural field infection, the 16 indica-japonica hybrids tested were highly resistant but the 16 japonica cultivars tested showed various degrees of resistance to leaf blast. With aging of rice plants, the quantitative levels of resistance to leaf blast increased in all the cultivars, although the levels of resistance to leaf blast varied according to rice genotypes. The leaf position of rice plants in which changed from susceptible to resistant reactions varied also with rice genotypes. The susceptible reactions of the rice cultivars to Pyricularia oryzae were distinctly changed to a resistant reaction on upper leaves of rice plants. The rice cultivars, in which the quantitative level of resistance to leaf blast was higher, were resistant on the lower leaves of rice plants. The cultivars Akibare, Palkeum, Jinheung, Olchal, Dobong and Ginga which drastically decreased blast infection at late growth stage were evaluated as adult-plant-resistant to leaf blast in the field. The adult-plant-resistant cultivars became resistant to leaf blast, both qualitatively and quantitatively, as rice plants matured.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.496-501
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• 1998

Incidence of rice blast on new rice cultivars and elite lines was observed from 1995 to 1997 in Icheon, Chuncheon, Jecheon and Naju areas. The observation was made in the nurseries and fields. In the nurseries, three cultivars Grubyeo, Sangjuchalbyeo and Suwon 414 showed moderate levels of resistance to leaf blast, with the disease index 0 to 5. From the field observation, it was found that cultivars Heugjinjubyeo and Unbong 18 were highly resistant to leaf blast, but susceptible to neck blast. In general, there was a great variation yearly and regionally in the incidence of neck blast within the same cultivar, ranging from 0 to 100%. However, the range of neck blast infection was relatively narrower in the cultivars Yunghaebyeo (0∼2.4%) and Suwon 414 (0∼2.2%) during observation period. Races of rice blast fungus were variable at different areas. Among them dominant races were KI-409, KJ-201 and KJ-301.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.2
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• pp.73-80
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• 1993

A simplified physiologically-based dynamic model, SIMRIW was selected for predicting the growth and yield of rice. The applicability of the model to the rice cultivars and weather conditions in the Republic of Korea was evaluated. Parameters of the model were calibrated using actual rice yields in Suweon region and an optimization scheme, Constrained Rosenbrock Algorithm. The simulated results from the calibrated model were in good agreement with the field data. The model with parameters calibrated for Suweon was applied to other five regions for the evaluation of transferability, but the simulated results fell short of satisfaction. However, the model is found to be applied to real-time prediction of the growth and yield of rice crop, which is believed to be useful for timely rice crop management, agricultural policy making, and optimal irrigation water management.

• Microbiology and Biotechnology Letters
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• v.31 no.2
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• pp.197-200
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• 2003

In oil-contaminated environments, anaerobic biodegradation of toluene depended on the concentration and distribution of terminal electron acceptor as well as the physicochemical properties such as DO concentration, redox potential and pH. This study showed the anaerobic biodegradation of toluene in two different soils by using nitrate reduction, ferric iron reduction, sulfate reduction and methanogensis. Toluene degradation rates in the soil samples taken from rice filed and tidal mud flat by nitrate reduction were higher than those by other processes. Tho soil samples from the two fields were enriched for 130 days by providing toluene as a sole carbon source and nitrate or sulfate as a terminal electron acceptor. The toluene degradation rates in the enriched denitrifying consortia obtained from the rice field and tidal mud flat soil were 310.7 and 200.6 $\mu$mol$ L^{-1}$ / $d^{-1}$, respectively. The toluene (legradation rates in the enriched sulfate-reducing consortia from the fields ranged fi-om 149.1 to 86.1$\mu$mol $L^{-1}$ / $d^{-1}$ .

• The Korean Journal of Ecology
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• v.24 no.2
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• pp.77-80
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• 2001

We investigated the habitat use of cranes, and suggested the proper way to protect and manage the cranes in Cheolwon Basin, which is the most important wintering ground of cranes in Korea. Field surveys were conducted in the wintering seasons from Nov. 1994 to Feb. 1995, and from Nov. 1997 to Feb. 1998. The habitat loss and environmental changes by the road construction and agricultural field rearrangement might have affected the distribution of the cranes. The distribution of cranes seemed to be related with the density of rice grains remained in rice paddies.

• The Plant Pathology Journal
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• v.26 no.3
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• pp.271-272
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• 2010

Burkholderia glumae causes bacterial rice grain rot and bacterial wilt on many field crops. We developed a simple diagnostic streak method for the isolation of B. glumae from diseased plant material. The geographical distribution of 178 Korean isolates shows that B. glumae is widely spread in South Korea.