• Korean Journal of Soil Science and Fertilizer
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• v.28 no.2
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• pp.176-182
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• 1995

Field and pot experiments were carried to find out the effects of direct application of phosphate rock powder on soybean plant in upland soils with different available P content. In newly reclaimed upland soil with extremely low available P, phosphate rock powder was superior to single superphosphate at the application rate of 400kg-600kg/ha, in the first year particularly. In the second year, however, the reverse was the case excepting at the rate of 200kg/ha. In upland soil with low avialble $P_2O_5$($52mg\;kg^{-1}$), the application of phosphate rock powder at the high appliaction rate(400-600kg/ha) increased the yield of soybean remarkably in the first year and there was residual effect in the second year. The application of phosphate rock at high rate, increased the P and Ca contenl of plant and soil. The concentration of all fractions of P in the soil at the harvest was higher in phosphate rock treatments than in single superphosphate and fused magnesium phosphate treatments. In this soil with low avaiable P the occurrence of different fractions of P was in the order of Org-P>Fe-P>Ca-P>Al-P, in the first year and there was no change in the second year.

• Korean Journal of Organic Agriculture
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• v.22 no.4
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• pp.761-771
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• 2014

The study was conducted to evaluate effects of weed managements after false seedbed on the weed control and growth of spring and fall cabbages (Brassica oleracea L.) in an organic upland in 2013. Weed managements included rake, flame, PE mulch, and none treatment. The weed occurrence was not effectively controlled by rake treatment but controlled by flame treatment in spring and fall cultivation. PE mulch plots had 30% of tip-burn in spring cultivation. Weed managements after false seedbed were similar fresh weight, leaf number, and cabbage yield to the conventional PE mulch. Head of cabbage was the lowest on the none treatment. Fall cultivation reduced the weed density and increased yield of cabbage compared to those of spring in all treatment plots. In conclusion, rake or flame treatment after false seedbed markedly decreased weed occurrence, which was expected to use for management of environmentally-friendly vegetation as a substitute of PE mulch.

• Korean Journal of Agricultural Science
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• v.46 no.2
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• pp.219-228
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• 2019

The forest of the Huaphanh Province (HP) has continued to decrease at 0.6% (10,560 ha) per year from 1992 to 2010. In the past few decades, the government of Laos and the Huaphanh Provincial Authority have been trying to address the root causes of deforestation. This study attempts to examine the factors effecting the decrease of the forest cover in the HP by analyzing the influence of the local socio-economic development and implementation of forest management policies on changes in the forest cover. The social data of the province focused on population growth and distribution between urban and rural areas including the number of poor people and the economic growth of three sectors, namely agriculture and forestry, industry, and service, while the implementation of the state forest management policy focused on the state forest management plan, tree plantation, forest land use planning and allocation to households, and shifting cultivation including annual upland rice and maize cultivation. In addition, government reports on socio-economic and rural development including poverty eradication of other provinces, where an increase in the forest cover was observed, were also collected and analyzed using qualitative and comparative analysis. The results from this study indicate that the decrease in forest cover in the Huaphanh Province appears to depend on a very slow economic growth and reduction in rural poverty of the province. The increase in the rural population in the province led to an increase in farm households and are as for shifting cultivation. As a result, forests were cleared leading to a decrease in the forest cover.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.3
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• pp.123-135
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• 2006

Spatial variability and distribution map of soil properties and the relationships between soil properties and crop yields are not well characterized in agroecosystems that have been land leveled to facilitate more cultivation of the new reclaimed sloping highland. Potato, onion, carrot, Chinese cabbage and radish were grown on the coarse sandy loam soil in 2004. Soil moisture content, soil penetration resistance and crop yield were sampled in the $10m{\times}50m$ field consisted of five plots. Sampling sites of each cultivation plot were 33 for the soil moisture, 11 for the soil penetration and 33 for the crop yield. The results of semivariance analysis, most of models were shown spherical equation. The significant ranges of each spatial variability model for the soil moisture, soil penetration and crop yield were broad as 33-35 meters in the potato cultivation plot, and that in the Chinese cabbage cultivation plot was narrow as 5-6 meters. The coefficient of variances (C.V.) of moisture, penetration and yield were various from 14 to 59 percents in five cultivation plots. The highest C.V. of potato yield was 59 percents, and that of the radish cultivation plot was as low as 14 percents. The required sample numbers for the determination of soil moisture content, soil penetration resistance and crop yield with error 10% at 0.05 significant level were ranged 8-40 for soil moisture, 7-25 for soil penetration and 424-4,678 for crop yield. The variogram and distribution map by kriging described field characteristics well so that the spatial variability would be useful for soil management for better efficiency and precision agriculture in the reclaimed highland.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.1
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• pp.49-56
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• 1993

The net flux of global green house gases such as carbon dioxide($CO_2$), methane($CH_4$), and nitrous oxide($N_2O$) emitted from the rotation of paddy-upland soil during growing sesaon under different cropping system was determined. The results obtained were summarized as follows : 1. The net flux of $CO_2$ during the growing season was the highest from continuous cultivation of rice but the lowest from rotation cultivation of rice-soybean. Under the different cropping system the highst emission was from soil of continuous cultivation of rice, but the lowest from converted system. 2. The net emission of methane was the highest from the sold of continuous cultivation of rice, but the flux was remarkably decreased by differing the cropping system. 3. $N_2O$ was emitted greatly from the every two year rotation of potato-chinese cabbage and the next rank was from continuous cultivation of rice, but was decreased notably from rotation cultivation of rice-soybean and potato-chinese cabbage under rotation of paddy-upland cropping system. 4. The ratio of oxygen and carbon dioxide in the soil air was much different with glowing season, the ratio was varied with 4~10 percents for oxygen and 1~22 percents for carbon dioxide. The ratio of carbon dioxide was dozens or hundreds times to that of air, and the variation was very high also. 5. The emission of global green house gases such as carbon dioxide, methane and nitrous oxide was affected by the moisture, temperature and nutrients of soils and the growth period of crops.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.2
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• pp.95-102
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• 2023

This study was to investigate the cultivation technique previously conducted cultivation research for the stable production of alfalfa and to present further research. The data used in the study were 270 alfalfa cultivation experimental data from 1983 to 2008, indicating the cultivation region, field type, variety, sowing, cutting frequency, fertilization, and dry matter yield (DMY). The average DMY of alfalfa in the Republic of Korea was 12,536 kg/ha, which differed greatly depending on the cultivated region. Most of the field type was cultivated in upland. In order to increase alfalfa production, it is necessary to use reclaimed and unused land, and research on the soil amendment matter to improve the soil condition is needed. Alfalfa varieties cultivated an amount of 53, but collected data no studies considered fall dormancy, the criteria for selecting alfalfa varieties, so further research is required. The fertilizer did not consider each component at various levels, and research is needed as the demand for fertilizer. In particular, research on potassium is needed considering the increase in alfalfa production. The alfalfa cutting frequency differed in the estimated pasture production period depending on the region, and the DMY tended to increase with increasing cutting frequency. This suggests that the alfalfa DMY can be increased according to the cutting frequency in the Republic of Korea, so research is needed to present the appropriate cutting frequency.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.327-334
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• 2023

The cultivation period of mung beans (Vigna radiata L.) in Korea has undergone recent variations. However, limited research has been conducted on pod shattering and sprout characteristics of mung beans on different sowing dates. This study aims to compare pod shattering and sprouts productivity based on different sowing dates. The research was was conducted with six different sowing dates (early May, mid-May, early June, mid-June, early July, and mid-July) in 2021 and 2022. Delayed sowing dates resulted in shortened days to germination, flowering time, and maturity time, whereas plant height, branch number, and node number increased. In addition, stem thickness and the number of pods per plant decreased. In the mung bean cultivar 'Sanpo', the pod shattering rate ranged from 10.0% to 19.3%, consistently lower than that of 'Dahyun' across all six sowing dates. The sowing date associated with the lowest shattering rate was early June. 'Sanpo' sown in early July and 'Dahyun' sown in mid-May exhibited the highest sprout production, at 871% and 750%, respectively.

• 한국약용작물학회:학술대회논문집
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• 2011.09a
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• pp.150-151
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• 2011

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.4
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• pp.241-244
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• 2000

This experiment was conducted to evaluate the effect on evapotranspiration and yield of soybean according to different soil water conditions, and to find the optimum time and amount for irrigation in soybean cultivation. The difference between potential evapotranspiration (PET) and maximum evapotranspiration (MET) during growing season of soybean planted in lysimeter was higher during reproductive stage than during vegetative one. The maximum crop coefficient was obtained at beginning seed stage of soybean. Soil water coefficient of irrigation treatment was higher than that of non-irrigation treatment during soybean growth stage in field experiment. Grain yield was highest in lysimeter due to its high water use efficiency and evapotranspiration rate.

• 한국약용작물학회:학술대회논문집
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• 2012.05a
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• pp.85-86
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• 2012