• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.4
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• pp.305-308
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• 2004

Recently, with increasing concern for sustainable agriculture and safe agricultural products, organic farming has become widely adapted as an alternative to conventional farming. This study was conducted to investigate the effects of earthworm casts (EWC) with $100\%$ organic compost on the growth and yield characteristics of fall-cropping potato (Solanum tuberosum L. cv. Dejima) in Jeju. The treatments consisted of seven plots: 2-, 4-, 6-, 8-, and 10-ton $ha^{-1}$ EWC-treated plots, 1.2-ton $ha^{-1}$ complex fertilizer $(N-P_2O_5-K_2O,\;10-10-14)-for-potato$ (CEP)-treated plot as conventional practices, and a control plot. The plant heights were greater in the plots where EWC and CFP were applied than in the control plot. Tuber diameter, number of stems per plant, and chlorophyll level tended to increase in the plots where 8-10 tons $ha^{-1}$ of EWC were applied. The application of CFP and EWC showed an increment in the average tuber weight per plant, but there was minimal significant difference. The application of 8-10 tons $ha^{-1}$ of EWC resulted in an increase in the total tuber yield (21.61-21.87 tons $ha^{-1}$) as compared to the other plots. The highest yield of market able tubers was $69.8\%$ of the total yield from the 10-ton $ha^{-1}$ EWC-treated plot. Consequently, with regard to the growth and yield characteristics of fall-cropping potato, the effects of EWC application were more favorable than the effects of the application of a chemical fertilizer.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.459-468
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• 2019

Changes in growing periods and productivities of crops under double cropping of potato-rice, potato-soybean and potato-maize, were investigated at the Paddy Experimental Fields in Miryang City from 2015 to 2018. Spring potatoes planted in early March showed a yield of 2.1-2.3 ton/10a and a period of 90 days. In double cropping, growing period of rice, soybean, and maize was about 130, 125 and 115 days, respectively. The potato yield obtained was as much as 616, 330 and 815 kg/10a under double cropping with rice, soybean and maize, respectively. It is beneficial to sow the spring potatoes as early as possible to increase the yield and to secure the growing period of sequential crops. The introduction of summer medium-late variety grain crops into double cropping of spring potato and rice as well as into double cropping of spring potato and soybean/maize, was possible because of no sowing in the fall and plants were able to reach the heading growth stage before the safe heading limit of rice in particular. In the case of maize, the growth period was different according to the change in temperature over the year. The introduction of upland crops such as soybeans and maize instead of rice improved soil physicochemical properties in a short period of time, contributing to the increase of spring potato yields, but there was also a risk of damage by successive cropping for more than three years. Spring potato-maize showed higher yield in terms of starch production, and spring potato-soybean was found to be advantageous for net income.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.728-733
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• 2010

This study was carried out to estimate carbon emission using LCA and to establish LCI database of potato production system. Potato production system was categorized into the fall season potato and the spring season potato according to potato cropping type. The results of collecting data for establishing LCI D/B showed that input of fertilizer for fall season potato production was more than that for spring season potato production. Input of pesticide for spring season potato production was much more than that for fall season potato production. The value of field direct emission ($CO_2$, $CH_4$, $N_2O$) were 2.17E-02 kg $kg^{-1}$ for spring season potato and 2.47E-02 kg $kg^{-1}$ for fall season potato, respectively. The result of LCI analysis focussed on the greenhouse gas (GHG), it was observed that carbon footprint values were 8.38E-01 kg $CO_2$-eq. $kg^{-1}$ for spring season potato and 8.10E-01 kg $CO_2$-eq. $kg^{-1}$ for fall season potato; especially for 90% and 6% of $CO_2$ emission from fertilizer and potato production, respectively. $N_2O$ was emitted from the process of N fertilizer production (76%) and potato production (23%). It was observed that characterization of values of GWP were 8.38E-01 kg $CO_2$-eq. $kg^{-1}$ for spring season potato and 8.10E-01 kg $CO_2$-eq. $kg^{-1}$ for fall season potato.

• Research in Plant Disease
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• v.12 no.1
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• pp.28-31
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• 2006

One of major potato viruses is Potato virus Y (PVY) in Korea. In the southern part of Korea, potatoes have been grown as double crops in a year by using cv. 'Dejima' and 'Chubak' due to very short dormancy. However, they have caused a serious problem such as a rapid degeneration. It has been thought that the degeneration is affected by the high incidence of PVY in neighboring potato fields. Therefore, the investigation of factors causing the degeneration is very important in the production of healthy seed potato. In this study, the PVY reinfection rates of several potato varieties and the different seed sources of cv. 'Chubak' have been investigated. Results show that the lowest infection rate of PVY among four potato cultivars derived from minitubers is cv. 'Superior'. The others are in order of 'Dejima', 'Atlantic' and 'Chubak'. Also, the incidences of PVY differ significantly when several seed sources are examined. When the seed potatoes (G2, the progeny of microtuber) as spring potato crops are planted in area without potato field nearby, the infection rate of PVY is as low as that of microtubers. However, PVY incidence in the progenies of minitubers as fall potato crops largely increases. Therefore, the best way of potato production under double cropping system is to use the healthy seed potato produced in area without potato field and plant relatively resistant cultivar such as Dejima.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.201-206
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• 1999

For the mass production of plug seedlings in cultivar ‘Dejima’ potato (Solanum tuberosum L.) the optimal apical cutting diameter for rooting and rapid multiplication of stem cuttings in hydroponics were determined. In addition, the best planting date was predicted to increase tuber yield of plug seedlings at fall cropping in Cheju-Do, Korea. Days to initial rooting decreased as the cutting diameter was reduced. Plant height, leaf number, root length and root weight per plant were favorable as the cutting diameter was small. The ideal cutting diameter was 1-2 mm in this experiment. In the hydroponic cultures, the Japanese standard (JS) nutrient solution was the most effective for multiplication of stem cuttings. It was able to propagate more than 20 times a month from a single mother plant. Viability of plants, which were derived from plug seedlings using stem cuttings, was excellent when transplanted to the field. The number of tubers and tuber yield in both of the plug seedlings and seed potato planting plots were high when planted on 25 August. The number and yield were reduced when planted on 15 August, 5 September and 15 September. The degree of decrease of tuber yield in the plug seedling planting plot however, was lower than that of seed potatoes when the planting date was late. In the case of small tubers (under 30 g), the number of tubers and tuber yield were evidently increased in the seed potato tuber planting plot; the yield of large tuber (over 80g) in the plug seedling planting plot was higher than that of the seed potato. The total tuber yield per plant in the plug seedling planting plot was less than that of the seed potato; therefore, in order to increase tuber yield it was necessary to increase field plant density.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.1
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• pp.31-37
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• 2010

Two field experiments were carried out in 2002 to evaluate effects of the sizes of tubers produced through a wick-based hydroponics on growth and yield of seed potatoes (Solanum tuberosum L. 'Dejima'). Nine sizes of seed tubers (<1, 1~3, 3~5, 5~7, 7~10, 10~20, 20~30, 30~50, and 50~80 g) were used in spring crop. In fall crop, however, tubers except for the 1 g and 50~80 g wereused with tubers 7 and 15 g produced through aeroponics. Emergence rate greatly increased as tuber size was increased up to 10~20 g and then leveled off in both croppings. The number of days from planting to emergence in spring crop was about 34 days regardless of tuber size, while that in fall crop decreased from 34 to 16 days as tuber size increased from 1~3 to 30~50 g. The number of stems per plant, stem length and diameter, and leaf size tended to increase with tuber size. As the seed tuber size increased up to 10~20 g, the number of tubers per plant, average tuber weight, total and seed tuber yields linearly increased and then slowly increased with seed tuber size. Total and seed potato yields were not significantly different between tubers produced through a wick-based hydroponics and an aeroponics when similar sized tubers were planted in the fall cropping.