• Korean Journal of Soil Science and Fertilizer
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• v.39 no.6
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• pp.403-408
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• 2006

Fluvio-marine paddy soils in Korea consist of high silt content and have the hardpan located below 20~30 cm from surface soil. This properties cause poor rice rhizosphere conditions such as low permeability and porosity, high bulk density and hardness. The aims of this study was to investigate the effect of popped rice hulls compost(PRHC) on soil fertility changes in the Fluvio-marine plain paddy soils. Total nitrogen content and nitrogen mineralization rate of PRHC were 1.17 and 33.5, respectively, and its C/N ratio was 35.4. Application of PRHC increased the content of organic matter and exchangeable potassium and improved the bulk density and porosity. The content of $NH_4-N$ in soil was high in the PRHC plot until maximum tillering stage. An uptake amount of fertilized nitrogen was greater in standard fertilization plot at early growth stage, however, it was greater more in PRHC plots at the ripening period than in standard fertilization plot. Among the PRHC treated plots, uptake amount was the greatest in 50% PRHC plot during the all growth period. Nitrogen efficiencies were higher in PRHC plot during the all growth period. Rice yields in all PRHC plots were lower than in standard fertilization, however, the yield of 40% PRHC plot was similar with that of standard.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.4
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• pp.221-225
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• 1974

The field experiment was conducted to find out the effect of inoculation of Rhizobium and interaction between amount of nitrogen and inoculating in soybean with 4 replicated split plot design. Main plot was 4 level of nitrogen 0, 2, 6, 12kg/10a and subplot was inoculation and uninoculation. The results are summarized as follows. 1. The yield of soybean did not show any significant difference among nitrogen level or between inoculating but yield of inoculated plot was a little increased than that of uninoculation. 2. At four leaves stage and flowering stage, the weight of nodules in root was decreased with incresing amount of nitrogen significantly and uninoculation caused a reduction compared with modulation significantly and those tendency was same in plant height, and those difference among treatment was more distinct in four leaves stage than in flowering stage. 3. After harvest, total nitrogen content in soil was not only increased with increasing nitrogen level but also was more increased in inoculated plot than in uninoculated plot except nitrogen 0kg/10a level. Inoculation of Rhizobium raised 15kg of nitrogen per l0a at 6kg nitrogen level compared with uninoculation.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.2
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• pp.119-125
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• 1974

Uptake amount, percent translocation to grain and grain yield efficiency of N. P. K. Si were investigated with N. P. K simple trials (countrywide, 1967~69) and other nitrogen fertiltzer field trials in relation to yield class. 1) Uptake rate with yield increase were similar in all nutrients but silica showed greater yearly variation. 2) In N. P. K simple trials showing very low nitrogen efficiency(46kg grain/ nitrogen uptake kg) it and percent translocation increased with yield increase. 3) Nitrogen efficiency deacreased with the increase of nitrogen uptake and the decreasing rate depends greatly on fertilizer forms and variety. Nitrogen efficiency was greater in sandy loam where yield was higher than in clay loam. 4) Nitrogen efficiency positively correlated with percent translocation. 5) In high yielding fields yield was attributed only to the increase of nitrogen uptake, keeping efficiency around 50. 6) Major factor for high yield is considered as the increase of nitrogen efficiency rather than nitrogen uptake. 7) Phosphorus efficiency in N. P. K. simple trials was considerably low, suggesting too much uptake due to soil reduction.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.1
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• pp.77-83
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• 1983

Effects of rice straw application (particularly application method; surface placement and deep placement) on the biological nitrogen fixing activity of paddy fields and on the growth of rice plant have been investigated by the lysimeter experiment with Aragawa alluvial soil and Tochigi ando soil. 1. Nitrogen fixing activity of plow layer (0~1cm) was increased by the rice straw application, notably by the phototrophs, both deep placement and surface placement, between 1 and 2 months of initial growth stage of rice plant. 2. Surface placement method stimulated the nitrogen fixing activity more significantly them the deep placement method, and also showed good effects on the growth of rice plant. 3. The increased of effect on the nitrogen fixing activity of surface placed area was found to be originated from the applied rice straw and its neigh bouring area. 4. Nitrogen fixing activity of surface placed rice straw was rather promoted by the application of herbicides (2, 4, 6-arichlorophenyl ether) than the non-applicated plot.

• Microbiology and Biotechnology Letters
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• v.14 no.2
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• pp.187-192
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• 1986

The inoculation effect of the highly nitrogen fixing strains of R. japonicum were tested in the 3 kinds of soil with different cultural history onto Gycine max cv. Jang-yeob. The nodulation and nitrogen fixation activity in 3 test soils all showed the great increase in inoculated group compared to the non-inoculated group. The plant dry weight of the in-oculated groups were increased about 10% than that of the non-inoculated groups. The numerical index of the increase in total nitrogen fixation activity were 238% in the pre-cultivated, 266% in the immatured and 157% in the matured soil and these results suggested the clear effect of inoculation. Among the strains tested, R. japonicum R214 and Rl38 showed the excellent inoculation effect.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.5
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• pp.365-372
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• 2013

Crop development and nutrient availability are strongly influenced by soil salinity levels. This study was conducted to investigate the effect of rice straw and nitrogen (N) fertilizer for silage barley under various soil salinity levels at Saemangeum reclaimed tidal land. Three levels of rice straw (0, 2.5, 5.0 ton rice straw $ha^{-1}$) and N (0, 150, 225 kg N $ha^{-1}$) were applied at 0.04, 0.23, 0.35% soil salinity levels. Biomass yield of silage barley was influenced by the interactions between rice straw application and N fertilization. Although there was no single effect of rice straw application on biomass yield, it was significantly increased with N application and a rice straw application of 5.0 ton $ha^{-1}$. Sodium content in silage barley was significantly lower at 0.04% salinity level, and but it was statistically increased with increasing soil salinity levels. Forage qualities such as total digestible nutrients and relative feed value of silage barley were significantly higher with N application at 0.04% salinity level, but there was no effect of rice straw application. Soil organic matter content was increased with N and rice straw application regardless of soil salinity level. The results of this study showed that the effect of rice straw and N fertilization on silage barley was influenced by soil salinity levels, which indicates that the management practice of silage barley at Saemangeum reclaimed tidal land should consider soil salinity levels.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.4
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• pp.453-462
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• 2010

Nowadays, the challenges of ensuring good water quality and quantity of river are becoming more important for human society, but there has been troublesome for purifying river water. In this study, we performed the fundamental study of a river water treatment system using riverside soil and eco-friendly optimal media for improving river water quality and can also treat a large amount of river water. As the results of the physical and chemical characterization of the two different soils (Kyungan and Chungrang, The Republic of Korea), which were collected from real stream sides in the Han River basin, and five kinds of media (zeolite, perlite, steel slag, woodchip and mulch), both soils were all classified as a sand, and effective size ($D_{10}$) and uniformity coefficient (U) of the soil were about 0.2 mm and 4 or so, respectively. Through the batch and column experiments with the soil and eco-friendly media, zeolite and mulch were found to be efficient for decreasing nitrogen. In addition, steel slag was especially superior to the other media for phosphorus removal. From soil reforming tests volume ratios were 2.8, 1, and 1 of Kyungan soil, zeolite, and steel slag hydraulic conductivity of mixed soil was increased $1.30{\times}10^{-2}$ from $2.85{\times}10^{-3}$ of Kyungan soil, and the removal efficiencies of nitrogen and phosphorus were also improved. These results show that reforming of the soil enhanced the purification of a large amount of water, and zeolite, mulch, and steel slag might be facilitated as proper functional media.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.2
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• pp.110-115
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• 2003

The iufluence of abandonment of agricultural fields on soil carbon and nitrogen dynamics is rarely addressed due to lack of appropriately paired sites. In this study, we identified three sites that have native forest and abandoned rice and crop fields at Mt. Kumdan near Seoul. Currently the vegetation of indigenous forest and the abandoned rice field is deciduous hardwood forest, while that of the abandoned crop field is deciduous shrub. We measured soil $CO_2$ evolution and inorganic N availability for the three sites from 25 July 2002 through 24 January 2003. Soil $CO_2$ evolution tracked seasonal soil temperature. Mean soil $CO_2$ evolution (g $CO_2$/$m^2$/hr) for the study period was 0.42 for the rice field to forest, 0.50 for the crop field to shrub, and 0.41 for the indigenous forest, respectively. Soil $CO_2$ evolution and soil temperature were not different among the sites; however, soil water content was significantly different. Soil water content had a very weak influence on soil $CO_2$ evolution. Inorganic resin N availability differed among the three sites and seemed to be related to soil moisture.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.1
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• pp.47-48
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• 1979

To study on the state of nitrogen fixation of Lemma associated with blue green algae this experiment was carried out. The results were as follows: 1) The blue green algaes associated with Lemnaceae were mainly Calthrix sp. and Microcrate sp., but Anabaena sp. was found only in L. gibba. 2) It was believed that Lemnaceae associated with blue green algae have semi-symbiotic nitrogen fixation ability, especially clear in L. oligorhiza.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.6
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• pp.534-538
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• 2006

The effects of Rhizobium inoculant, compost, and nitrogen on nodulation, growth, dry matter production, yield attributes, and yield of pea (Pisum sativum) var, IPSA Motorshuti-3 were assessed by a field experiment. Among the treatments Rhizobium inoculant alone performed best in recording number and dry weight of nodules/plant. The highest green seed yield of 8.38 ton/ha (36.9% increase over control) and mature seed yield of 2.97 ton/ha (73.7% increase over control) were obtained by the application of 90 kg N/ha. The effects of 60 kg N/ha, Rhizobium inoculant alone and Rhizobium inoculant along with 5 ton compost/ha were same as the effect of 90 kg N/ha in recording plant height, root length, dry weight of shoot, and root both at preflowering and pod filling stages, number of mature pods/plant, number of mature seeds/pod, 1000-seed weight, green, and mature seed yields of pea.