• Korean Journal of Soil Science and Fertilizer
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• v.19 no.4
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• pp.301-305
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• 1986

This study was conducted to develop the homemade soil media adequate to raising rice seedlings for machine transplanting. A raising experiment of rice seedlings was tested on a newly developed soil medium made mainly from briquette ash compared to ones of infertile red earth and fertile paddy loams. Dry weight of rice seedlings at 36 days after seeding was slighly lower in the plot of briquette ash that in soils, however, it was quite good in the plot of briquette ash mixed with zeolite and diatomaceous earth. pH in soil media was high in briquette ash and also high in soils mixed compost compared with out compost treatment, resulting in higher occurrence of damping off or physiological disorder. Good rice seedlings could be raised in soil media without compost and briquette ash mixed with zeolite diatomaceous earth.

• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.105-115
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• 2019

Saline or alkaline condition in soil inhibits growth of most crop plants and limits crop yields in many parts of the world. Augmenting an alkaline soil with alkali-tolerant bacteria capable of promoting plant growth can be a promising approach in expanding fertile agricultural land. Near-shore environments of Dokdo Island, a remote island located in the middle of the East Sea, appear to have patches of seawater-influenced haloalkaline soil that is unsupportive for growth of conventional plants. To exploit metabolic capacities of alkali-tolerant bacteria for promoting plant growth in saline or alkaline soils, we isolated of alkali-tolerant bacteria from near-shore soil samples in Dokdo and investigated properties of the isolates. Alkali-tolerant bacteria were selectively cultivated by inoculating suspended and diluted soil samples on a plate medium adjusted to pH 10. Fifty colonies were identified based on their $GTG_5$-PCR genomic fingerprints and 16S rRNA gene sequences. Most isolates were affiliated to alkali-tolerant and/or halotolerant genera or species of the phyla Firmicutes (68%), Proteobacteria (30%) and Actinobacteria (2%). Unlike the typical soil bacterial flora in the island, alkali-tolerant isolates belonged to only certain taxa of terrestrial origin under the three phyla, which have traits of plant growth promoting activities including detoxification, phytohormone production, disease/pest control, nitrogen-fixation, phosphate solubilization or siderophore production. However, Firmicutes of marine origin generally dominated the alkali-tolerant community. Results of this study suggest that haloalkaline environments like Dokdo shore soils are important sources for plant growth promoting bacteria that can be employed in bio-augmentation of vegetation-poor alkaline soils.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.3
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• pp.125-132
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• 1979

A field experiment was conducted to evaluate the effectiveness of an organic fertilizer (Glutamic acid fermentation by product ameded with nitrogen) on the growth and yield of radish and chinese cabbage on a relatively fertile soil. Additional laboratory studies were also made to find out the influence of mentioned fertilizer on the phisical and chemical characteristic of soils. The results are summarized as following. 1. Effect of fertilizer on the growth and yield. a. On a relatively fertile soil with high organic matter content (3%), the organic fertilizer was not effective for the growth and yield of radish and yield of radish and chinese cabbage. b. The application of organic fertilizer increased the K contents in plants both in radish and chinese cabbage. It was observed that the high content of K in radish leave lowered the leaf/root ratio and the leaf/root ratio showed a positive correlation with root weight. 2. Effect on soil physical and chemical properties. a. The application of organic fertilizer resulted in the improvement of soil physical property by lowering bulk density and increasing porosity. b. It was found that application of organic fertilizer increased the water stable soil aggregates. c. The application of organic fertilizer did not result in the significant increase in soil organic matter. d. Soil pH was lowered by the application of organic matter. It was speculated that the oxidation of ammonical nitrogen in the fertilizer is responsible for the lowering of soil pH.

• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.205-217
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• 2019

The aim of this study was to identify land resources because food production and supply in North Korea have been at risk due to variations in its seasonal climate. More than three-fifths of the soils are locally derived from the weathering of granitic rocks or various kinds of schists developed from crystalline rocks. Well-developed reddish brown soils derived from limestone are found in the North Hwanghae province and in the southern part of the South Pyeongan province. Additionally, a narrow strip of similarly fertile land runs through the eastern seaboard of the Hamgyong and Kangwon Provinces. The loss of clay particles and organic matter are major causes of degradation in the soil physical and chemical properties in North Korea. 75% of the areas converted from forests became croplands, and 69% of the land converted to croplands came from forests. The net forest loss was quite small from the 1990s to the 2000s. However, deforestation in areas with a slightly lower elevation and gentler slope between 1997 and 2014 led to severe soil erosion resulting in a drastic change in the physical and chemical properties of the soil which influenced cropland stability and productivity. Therefore, the drastic changes in land cover as well as in the physical and chemical properties of the soil caused by various geographical features have seriously influenced the productivity of crops in North Korea.

• Horticultural Science & Technology
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• v.30 no.1
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• pp.73-78
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• 2012

KC00256, KC00406, KC00462, KC00463, KC00820, and KC00821, the genetic resources that have previously been reported as moderately resistant to Phytophthora capsici, as well as the line KC01322, a new source of moderate resistance introduced from Laos, were tested against two strains (Pc003 and Pc005) of P. capsici. We also determined the nuclear restorer genotypes of these lines, in regards to their interaction with cytoplasmic male sterility, through crossing the resources with cytoplasmic male sterile Punggok-A (Srfrf) and determining the fertility of the $F_1$ hybrids. The studied lines exhibited a low level of resistance to both the strains of P. capsici compared to highly resistant CM334, but their response was fairly consistent for both P. capsici strains. KC00406, KC00462, KC00463, and KC01322 produced stable, male fertile $F_1$ plants indicating that they are restorers with genotype N(S)RfRf. KC00821 produced male sterile $F_1$ plants and was identified as a maintainer with genotype Nrfrf. The $F_1$ plants of the KC00820 cross, however, set a few male fertile flowers in the greenhouse at seedling stage, then became male sterile after being transplanted to the plastic greenhouse soil in May and remained so to the end of the growing season. Therefore, KC00820 is an unstable maintainer with genotype Nrfrf. The moderate resistance exhibited by these genetic resources may be integrated into breeding programs aimed at promoting higher levels resistance via recurrent selection or hybridization.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.3
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• pp.242-249
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• 1983

The experiments were carried out in farmers' field to determine the yield response of corn to fertilizers for the three years (1976-1979) The results are summarized as follow: 1. The optimum application rates of N-P-K fertilizers on corn cultivars was 21.1-11.6-10.6 kg/10a for Suweon 19, 23.0-11.9-15.0 kg/10a for Boggyo 2 and 19.8-10.6-9.1 kg/10a for Hwangok 3, and 23.3-19.1-10.7 kg/10a in drained paddy soil. 2. The optimum application rates of N-P-K fertilizers was 23.4-15.5-13.2 kg/10a in fertile soil comparing with 27.0-15.6-18.8 kg/10a in the soil of low fertility. However yield was lower in soil of low fertility than in fertile soil even under the condition applied optimum amount. 3. Production efficiencies of each kg of N, P, K application for Suweon 19, Boggyo 2, and Hwangok 3 were 26.1-24.5-9.7, 17.8-13.3-2.0, and 14.6-21.5-4.2kg. respectively. 4. The optimum nutrient content in soil and plant to yield 1,000 kg/10a of corn was available phosphorus 200 ppm, exchangeable potassium 0.63 me/100g, potassium saturation rate 5.0% in soil, and nitrogen 2.86%, phosphorus 0.73%, potassium 2.80% in plant at tasseling stage.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.1
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• pp.2162-2176
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• 1971

From the ancient times our forefathers settled down in this peninsular and cultivated the hills and waste-lands into fields. Instead of fertilizing the lands they moved to find other fertile lands and lived a feudal life of agriculture and various machines played a main role in the land reclamation. The best method of land clearing, the time and efficiency in the operation and the effect of growing crops should sysematically analized prior to the time of 3rd Five-year Economic Development(1972-1976) in order to cultivated 210,000 ha of waste-land or the modernization of our country. The present study was investigated to find out a new working-system of mechanical land clearing and development of fertile soil. The results are as follows: 1) The land reclamation in natural slope is much more encourageable in land clearing and farming when the slope is below ten grades than bench terrace. 2) Weeds were mixed with soil in the land clearing work in order to supply organic materials and to make soil swollen instead of burning of just removing. 3) The equipments such as bulldozers, harrows, power tillers and so on should be prepared in order to do a systematic work in the land clearing. 4) The work of pulling-up roots is dependent upon the forms of roots spreading under the ground. The work of the pulling-up the straight roots was most difficult. 5) The land clearing work of the wrinkled style blocks was easy in pulling up roots and in the time of first plowing. The harrowing work could also be simply done. 6) The amount of soil carried was $240m^3/10a$, 15.6% increased amount from the standard block, while the required time of clearing work was 2 hours 15 minutes 45 seconds/10a, the one third of time required for the standard block. 7) The time disc harrowing work increased 50%, or 15 minutes/10a compared to the harrowing work required in the cultivated soil. 8) The time of rotary tilling increased 2.4 times or 1 hour 47 minutes 43 seconds/10a compared to the time required in the cultivated soil. 9) The reclamed land should be fertilized according to the soil quality, especially added fertilizer should be more than 1,200kg/10a, limes 20kg/10a. In order to produce added fertilizer grass fields should be needed. 10) The experiment of pasture growing is now progressing and therefore the effect of land clearing and the degree of developed soil will be investigated before long.

• The Korean Journal of Ecology
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• v.6 no.3
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• pp.153-166
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• 1983

The distribution of beech species (Fagus) and beech-dominated forests along climatic gradients in the Northern Hemisphere was studied by use of taxonomic and ecological literature. The genus Fagus as a whole occurs over the range of 4.5 to 20.0。C mean annual temperature and 600 to 1000 mm in lower limit, mean annual precipitation. At the higher end of the temperature range, beech occurs in zones with relatively high growing-season precipitation. Edaphically, beech species and beech-dominated forests tend to occur on mesic, moderately fertile sites. Beech-dominated forests occur in a limited portion of the climatic range of the genus with sensitive responses to other environmental factors. The distributional range of beech-dominated forests on a global scale depends more on climatic factors and geological events than on soil conditions or other factors, summarizing the facts obtained by many researchers on beech dominated forests.

• Mycobiology
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• v.34 no.1
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• pp.1-6
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• 2006

A Cordyceps species was found with a Beauveria anamorph state on larval insect cadavers on Obong mountains in Gangwon Provinces, Republic of Korea. Cultures from discharged ascospores formed an anamorph identifiable as Beauveria bassiana. This teleomorph-anamorph connection was also confirmed by the in vitro production of fertile ascomata from conidial cultures with morphology like that of field-collected specimen. This is the first report of in vitro production of a teleomorph for any Beauveria species. The Cordyceps species has been conspecified as Cordyceps bassiana, a species described from China with B. bassiana anamorph.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.2
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• pp.78-84
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• 1993

In order to know the effect of sludge from water treatment plants un agricultural environment, an experiment of water treatment sludge application for Altari radish (Raphanus sativus L.) was carried out. And the results were as follows ; 1. The pH of water treatment sludge was 7.2, which was higher than that of the experimental soil. The exchangeable Ca content in the sludge was very high being 29me/100g sludge. So when the sludge was applied to the soil, amending effect for soil acidity was supposed. 2. With the application of the water treatment sludge to the soil, soil pH and organic matter content were increased. With the increase of the level of sludge application, contents of crude fiber and Ca in Altari radish were increased, white those of P and Mg tended to decrease. 3. The length of the root and the amount of fresh yield of the whole plant of radish tended to increase with the increase of sludge application, and this tendency was more evident on the infertile soil. From the above results, it was concluded that the fresh yield of Altari radish increased up to 75ton/ha sludge application on the fertile soil, but the yield decreased when higher levels of sludge was applied. While on the infertile soil, the yield increased up to the application of 300ton/ha, and the heavier application level did not adversely affect the yield of Altari radish.