• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.662-668
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• 2016

No-tillage dry-seeding of rice can offer potential benefits by reducing time and labor cost compared with conventional tillage practices. This study was conducted to investigate the effects of no-tillage dry-seeding on rice growth and soil hardness in comparison with other rice cultivation methods, machine transplanting and wet-hill-seeding on puddled paddy. The seedling stand fell within optimum range for both no-till dry-seeding and wet-hill-seeding on puddled paddy. Plant height, number of tillers and SPAD values in no-tillage dry-seeding cultivation were higher than those observed in other methods. There were no significant differences in grain yield of rice among three cultivation methods. The quality characteristics of milled rice grown in no-tillage dry-seeding were similar to those grown in other cultivation methods. Soil hardness in top 10 cm depth was significantly higher in no-tillage dry-seeding than other cultivation methods, while soil hardness below 10 cm depth was highest in machine transplanting cultivation. Results indicate that no-tillage dry-seeding practice is comparable to conventional tillage system in terms of seedling establishment, growth, yield and grain quality.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.814-818
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• 2011

The seasonal changes were evaluated in the soil microbial populations by selected media in an organic farming system (OFS) with no-till management compared to those in a conventional farming system (CFS) with tillage and synthetic amendments in a flooded paddy from 2009 to 2010. The populations of aerobic bacteria and fungi in the OFS were significantly higher than those in the CFS at the harvesting stages, whereas those of Gram-negative bacteria was significantly higher in the OFS than in the CFS before the submerging stages. In addition, populations of aerobic bacteria, Gram-negative bacteria, and fungi tended to rapidly decreased after the submerging stages may be due to insufficient oxygen. Gram-negative bacteria should be considered as potential factor responsible for the microbial population differentiation observed between the OFS and the CFS in flooded paddy fields.

• Korean Journal of Organic Agriculture
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• v.7 no.2
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• pp.189-195
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• 1999

Under the no-till direct-sown rice-vetch cropping systems, where whole chopped rice straw were returned to the paddy surface at combine harvest and whole-plant of Chinese Milk Vetch(Astragalus sinicus L.) was submerged after direct-sowing, three levels of nitrogen top-dressed(0, 2, 4 kg N/10a) without basal N and two levels of sowing rate were applied into the paddy field in expectation of the enhancement of nitrogen efficiency and protection of agricultural environment in reduced N-fertilizer level. A cultivar, Dongjin, was direct-sown on May 30, 1996. Characteristics of rice growth and physicochemical properties of rice plant were observed. Under the system, reduced total N(4 kg N/10a) resulted in high panicle numbers. N-top dressed toward at later growth stages enhanced the ratio of panicle-producing tillers and at spikelet numbers per panicle. As N-level increases, DM yields of leaf and stem at heading were increased. Maximum grain yield was obtained at 4kg N/10a and major attributed factors to grain yield in this case were the number of grains per unit area and the ratio of ripened grain.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.5
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• pp.564-570
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• 1997

Field experiments were carried out to investigate the effects of different residue treatment of vetch sward on soil improvement, rice growth and grain yield from 1995 to 1996. With Chinese milkvetch, pH, Ca, and Mg of paddy soil were increased in subsoil(10~20cm soil depth), and organic matter, P$_2$ $O_{5}$, and K were increased in top soil (0~10cm soil depth). Redox potential of the paddy soil with milkvetch residue was severely reduced at earlier flooding period, and recovered gradually as rice growth continued. Weeds were more abundant in the paddy with unchanged vetch stand. The most dominant weed species in the paddy soil with vetch sward residue was Echinochloa crus-galli, followed by Leersia japonica, Polygonum hydropiper in the order of abundance. Seedling establishment ratio of rice directly sown over vetch-sward was lower than in conventional tillage paddy(no-vetch, tilled) condition. Rice growth pattern, however, was not significantly affected by vetch sward treatments. The number of tillers per square meter and plant height at heading date were not significantly different among the vetch-sward treatments. Grain yield was the highest in plough of vetch vegetation, followed by conventional (no-vetch, tilled), live-mulching of vetch, vetch-removed, and vetch-desiccated by weedcide. The whole grain rice yield was the lowest in vetch-desiccated by weedcide.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.6
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• pp.473-477
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• 2001

Chinese milkvetch (Astragalus sinicus L.) has been traditionally used as a green manure supplying mineral N and organic matters to soil. In rice-Chinese milkvetch interrelay cropping system, three rice cultivating methods (no-till direct seeding, no-till transplanting, and tillage transplanting) were evaluated for stand reestablishment without reseeding Chinese milkvetch with two cropping times (May 25 and June 4) for two years. Chinese milkvetch incorporated was decomposed rapidly in the first week. Decomposition was fast in topsoil than in subsoil. Natural milkvetch reestablishment (NMR), following harvest of no-till-direct-sown rice was good enough to cover the paddy field in both cropping times, but rice yield of this method was lower than that of transplanted rice on paddy field without milkvetch cultivation. Even though good NMR was secured in no-till rice transplanting, the shoot of milkvetch should be removed before machine-transplanting of rice seedlings. NMR was better in rice cropping at the mid-ripening stage of milkvetch (June 4) than at the late-bloom stage (May 25). Rice yield was higher in tillage transplanting at the mid-ripening stage of milkvetch (June 4) than in the other rice cropping method.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.91-97
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• 2011

The objectives of this research were to investigate the system of rice intensification (SRI) on early growth, grain yield, and yield components under Chinese milk vetch residue-mulched no-tillage cropping systems at silt loam soil. The field was prepared as a split-plot design with three replications, main plots consisted of Dongjinbyeo, and Sobibyeo as a cultivar, and subplots consisted of $10{\times}10$ cm, $20{\times}20$ cm, and $30{\times}30$ cm as a planting density. Weed infestation during rice growing season was more severe in wider planting density $30{\times}30$ at 35 days after transplanting (DAT), and $20{\times}20$ cm at 95 DAT in both Sobibyeo and Dongjinbyeo. The maximum plant height was recorded in Sobibyeo compared with Dongjinbyeo, $10{\times}10$ cm and $20{\times}20$ cm planting density compared with $30{\times}30$ cm from 20 DAT until 60 DAT. Among the three planting densities, SPAD values were significantly greater in planting density of $20{\times}20$ cm both in Sobibyeo and Dongjinbyeo followed by $30{\times}30$ cm compared with closer planting density of $10{\times}10$ cm. The lowest grain yield was observed in wider planting density of $30{\times}30$ in both Sobibyeo and Dongjinbyeo due to lower number of panicle per unit area. Our findings suggest that optimum planting density for SRI in no-tillage paddy was $20{\times}20$ cm and it should be useful the systems to small-scale rice farmers in Korea as a sustainable farming system.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.319-319
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• 2017

Methane is the main greenhouse gas released from rice paddy field. Methane from paddy fields accounts for 11 % of the global total methane emission. The global warming potential (GWP) of methane is 25 times more than that of carbon dioxide on a mass basis. It is well known that most effective practice to mitigate methane in paddy is related to the water management during rice growing season and the use of organic matters. This study was conducted to investigate the effects of tillage and cultivation method on methane emission in paddy. Tillage (tillage and no-tillage) and cultivation methods (transplanting and direct seeding) were combined tillage-transplanting (T-T), tillage-wet hill seeding (T-W), tillage-dry seeding (T-D) and no-till dry seeding (NT-D) to evaluate methane mitigation efficiency. Daily methane emission was decreased on seeding treatments (T-W, T-D, NT-D) than transplanting treatment (T-T). Amount of methane emission during rice growing season is highest in T-T ($411.7CH_4\;kg\;ha^{-1}y^{-1}$) and lowest in NT-D treatment (89.7). In T-W and T-D treatments, methane emissions were significantly decreased by 36 and 51 % respectively compared with T-T. Methane emissions were highly correlated with the dry weight of whole rice plant ($R^2=0.62{\sim}0.93$). T-T treatment showed highest $R^2$ (0.93) among the four treatments. Rice grain yields did not significantly differ with the tillage and cultivation methods used. These results suggest that direct seeding practice in rice production could mitigate the methane emissions without loss in grain yield.

• Proceedings of the Korean Society of Crop Science Conference
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• 1997.10a
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• pp.86-87
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• 1997

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.98-103
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• 2011

The System of Rice Intensification (SRI) is a new concept of increasing the yield of rice produced in farming. Therefore, we investigated the impacts of planting density on nutrient uptake as affected by SRI under no-till cropping system. The field was prepared as a randomized complete block design with three treatments: $10{\times}10$ cm, $20{\times}20$ cm and $30{\times}30$ cm planting densities. The root dry mass was significantly increased in the wider planting densities (p<0.05%). The highest grain yield was obtained in $20{\times}20$ cm planting density plot (p<0.05%) due to higher plant density per unit area and spikelets number per panicle. The total uptake amounts by rice plant were significantly higher in $20{\times}$20 cm planting density plot as 94.8 kg $ha^{-1}$ for T-N and 29.9 kg $ha^{-1}$ for P than other planting densities plots, but K and Mg uptake were significantly higher in $10{\times}10$ cm planting density plot (p<0.05%). In this study, our findings suggest that SRI should be considered as a new practice for the rice productivity.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.484-487
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• 2001

Runoff, sediments and nutrient losses were studied under different patterns of paddy field management: (1) fall and spring plowing (PL); (2) fall plowing for half of plot and spring plowing (SPL); (3) no-till for fall and spring plowing (NPL) during the non-cropping period in the southern Korea. Sediment losses from PL plot were 25% more than those from NPL plot. There was significant difference in nutrient losses via runoff water and sediment according to plowing practice (P < 0.01). Losses of total-N, ammonia-N, nitrate-N, total-P from NPL plot were larger than PL and SPL plots during study period. Sediment and total-P losses from SPL plot were close to those of PL plot.