• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.150-156
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• 2001

To explore the feasibility of recycled paper mulching in spring-grown potato the changes of soil environments and the growth and yield of potato under non-mulched control and three mulching treatments of recycled paper (RPM), transparent polyethylene film (TPFM), and black polyethylene film (BPFM) were examined over two spring seasons in 1998 and 1999 at Suwon, Korea. The mulching materials were a recycled mulch paper with 110 g/$m^2$ and a thickness of 0.1mm, which was manufactured from old corrugated containers for this experiment and the commercial polyethylene films with a thickness of 0.01mm. RPM lowered the average soil temperature at 5-cm depth during the potato growing period by 03$^{\circ}C$ compared with the control, whereas TPFM and BPFM raised it by 2.$0^{\circ}C$, and 1.8$^{\circ}C$, respectively. On a sunny day during sprout emergence, RPM reduced the maximum soil temperature by about 5$^{\circ}C$, while TPFM and BPFM enhanced it by about 11$^{\circ}C$ and 6.$0^{\circ}C$, respectively. The temperature difference between the control and the mulching treatments decreased with the development of canopy. All the mulching treatments had an advantage in preserving the soil moisture over the control. RPM and BPFM resulted in the effective control of weed by obstructing light transmission onto soil surface, but TPFM had no control effect of weed. Sprout emergence started two to three days earlier in TPFM and BPFM, but one day later in RPM than in the control due to the altered soil temperature by the mulching treatments. However, the final percentage of emergence was notably lower in TPFM than that in the control because of too high soil temperature during daytime, but was not different among the control, RPM, and BPFM. During the early stage of potato growth, the shoot and root growth under RPM was lower compared with the control, but afterwards, RPM outpaced the control. In 1998 experiment, the tuber yield under RPM and BPFM were significantly higher than those of the control and TPFM. In 1999 experiment, there was no significant difference in tuber yield between RPM and the control.

• Korean Journal of Plant Resources
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• v.18 no.3
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• pp.512-517
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• 2005

To establish the economical cultivation method of Gastrodia elata Blume by controlling the shading rate and the mixing ratio of recycling spawn bed logs, a serial experiment was carried out. When G. elata was grown in the field with no shading, the yield of spawn tuber was higher than that of tuber of G. elata. The yield of G. elata was high in the rainproof green house covered with one layer of $95\%$ shading net, in the rainproof green house covered with two layers of $95\%$ shading net, and in the field with no shading, in that order. In the case of mixing ratio of recycling spawn bed logs, the yield was high in the fresh logs, in the mixing ratio of 2:1, and the ratio of 1:1, in that order. The income of the rainproof green house covered with one layer of $ 95\%$ shading net which brought the best yield was $81\%$ in the mixing ratio of 2:1 over the fresh logs.

• Korean Journal of Plant Resources
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• v.32 no.1
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• pp.38-44
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• 2019

This study was conducted to establish a domestic cultivation system of a newly introduced yam bean (Pachyrhizus erosus L.). Growth and yield were investigated in response to various cultural practices, such as seedling raising, planting distance, pinching, and flower pruning. Optimum conditions for raising of seedling were an average temperature of $22^{\circ}C$ for 30 days. Considering of the raising efficiency and the convenience of transplanting, 128 cells per tray was a suitable size. When pinching at a height of 120 cm from late July to early August, yield increased by 22% compared to no pinching. Flower pruning between late August and early September increased the number of tubers and tuber yield by 32% in comparison with no flower pruning. Yam bean seedlings planted at $50cm{\times}30cm$ spacing resulted in 30% yield increase as compared to wider spacing of $100cm{\times}30cm$. Our results thus suggested that the optimal combination of cultural practices ($50{\times}30cm$ planting distance, pinching at 120 cm height, and one time of flower pruning) increase profitability by 107%. All these results suggest high possibility of yam bean as a new income crop in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.3
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• pp.195-202
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• 2017

The volcanic ash soils from the Jeju province have low available phosphate because of the high phosphate fixing power of the soils. Phosphorus fertilizerwas dressed after cultivating green manure crops and before cultivating potatoes in order to investigate potato yields, the available phosphate contents, and phosphorus balance in the soils. Green manure crops cultivated in this study were hairy vetch alone and hairy vetch and rye. During potato cultivation, four treatments were conducted in the experiments; NF (non fertilizer), P fertilizer ($N-P-K=0-25-0kg\;10a^{-1}$), NK fertilizer ($N-P-K=18-0-19kg\;10a^{-1}$), and NPK fertilizer ($N-P-K=18-25-19kg\;10a^{-1}$). There were no differences in the yields of potato stem and tuber from the cultivation plots of different green manure crops. However, in the plots with single-sown hairy vetch and mixed-sown hairy vetch and rye, the yields of potato stem and tuber were higher in the P fertilizer plot than in NF plot. The yield of tuber among the treatments with mixed-sown hairy vetch and rye was the highest in the NPK fertilizer plot. The available phosphate content in soils initially increased with time in all plots, but began to decrease gradually after Oct. 18. The available phosphate contents were high in the plots for phosphate fertilization, and the difference in available phosphate content between non-phosphorus fertilizer plots and phosphorus fertilizer plots increased with time. In the single-sown hairy vetch and mixed-sown hairy vetch and rye plot, the phosphorus balances in NF plot and NK fertilizer plot were very low, while those in the P fertilizer plot and NPK fertilizer plot were high. In conclusion, available phosphate contents in soil and the potato yields were increased by phosphorus fertilization when potatoes planted after cultivating hairy vetch and rye together, compared to hairy vetch alone.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.1
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• pp.1-5
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• 2001

Field experiment was conducted during 1993-94 season to determine the pattern of nutrient uptake and productivity of maize/sweet potato intercropping system. Four levels of nitrogen (0, 50, 100 and 150kg N ${ha}_{-1}$) and four levels of potassium (0, 40, 80 and 120kg $K_2$O ${ha}_{-1}$) formed treatment variables. Plants were sampled periodically to determine dry matter and tissue concentrations of N and K in the individual plant components of intercropped maize and sweet potato. Nitrogen and potassium fertilizer did not interact significantly to nutrient uptake by any plant parts of intercropped maize and sweet potato. But application of N fertilizer independently enhanced N uptake in all the plant parts of maize and sweet potato. The uptake of N in leaf, leaf sheath, stem, husk, and cob of maize increased upto 90 days after planting (DAP) but grain continued to accumulate N till its maturity. Sweet potato exhibited a wide variation in N uptake pattern. Sweet potato leaf shared the maximum uptake of N at 50 DAP which rapidly increased at 70 DAP and then declined. Declination of N uptake by petiole and stem were observed after 120 DAP whereas N uptake by tuber increased slowly upto 90 DAP and then rapidly till harvest. Rate of applied K had very little effect on the uptake patterns in different components of intercropped maize. Pattern of K uptake by leaf, petiole and stem of sweet potato showed almost similar trend to N uptake. But uptake of K by tuber increased almost linearly with the K application. Pattern of N and K uptake by grain and tuber paralleled the grain yield of maize and sweet potato respectively. Intercropped productivity of maize and sweet potato found to be better by the application of 100kg N and 120 kg $K_2$O ${ha}_{-1}$

• Horticultural Science & Technology
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• v.19 no.4
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• pp.515-520
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• 2001

To observe the stimulating effect of low dose ${\gamma}$ radiation on the dormancy breaking and growth, microtubers of two potato cultivars (Solanum tuberosum L. cv. Dejima and cv. Superior) were irradiated at the dose of 0.5-30 Gy. Though it varied with cultivars and storage duration, sprouting rate, plant growth and tuber yield were promoted by 2-8 Gy irradiation in microtuber of 'Dejima' stored at low temperature. On the other hand, in microtuber of 'Superior', sprouting rate was promoted by 2 and 4 Gy irradiation, and the growth and tuber yield by 4 Gy irradiation. These results suggest that low dose of ${\gamma}$ radiation could have stimulating effects on the dormancy breaking of microtuber and potato growth.

• Korean Journal of Environmental Biology
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• v.19 no.4
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• pp.270-277
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• 2001

To observe the stimulating effect of low dose ${\gamma}$ radiation on the dormancy breaking and growth, microtubers induced in vitro of two potato (Solanum tuberosum L. cv. Dejima and cv. Superior) cultivars with different storage duration were irradiated with ${\gamma}$ radiation at the dose of $0.5{\sim}30$ Gy. Sprouting rate, growth and tuber yield of ‘Dejima’ microtuber were increased by ${\gamma}$ radiation in the range of $2{\sim}16$ Gy. In the microtuber of ‘Superior’, the sprouting rate was promoted by 2 Gy and 4 Gy irradiation, and the growth and tuber yield by 0.5 Gy and 4 Gy irradiation. There were not that much difference in chlorophyll content of potato plantlet by the low dose ${\gamma}$ irradiation. These results suggested that low dose ${\gamma}$ radiation stimulated the dormancy breaking and potato growth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.8 no.1
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• pp.83-89
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• 1970

Investigation was made to know the effects of the time of transplanting and harvesting, fertilizer, soil texture and period of storage on tuber yield and starch content of sweet potato. Variety used was Shin-mi, one or the leading varieties in Korea. Late transplanting, early harvesting, and balanced application of nitrogen, phosphorous and potassium, and loam and coarse sandy loam were more effective in increasing starch content than early planting, late harvesting, and more application of potassium and none application of phosphorous, and light clay respectively. Long storage period resulted in reducing starch content.

• Research in Plant Disease
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• v.11 no.2
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• pp.122-127
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• 2005

Late blight of potato caused by Phtophthora infestans is one of the most destructive disease in organic farming as well as in the conventional cultivation in Korea. Incidence and progress of the disease largely depend on climatic conditions around the fields. However, the disease completely destroys whole leaves of the plant within two weeks in organic farming fields. While, potato leaves in conventional farming fields remain healthy for 5 weeks after the first symptom appearance, because fungicides were applied four times in average to control the disease. Area under disease progress curve (AUDPC) of organic farming fields ranged from 2314 to 2421 and quickly expanded compare to that of conventional farming fields. The tuber yield in the organic farming fields ranged from 0.96 ton per 10a to 1.5 ton per 10a, while it was 2.7 ton per 10a in conventional farming fields. Tuber yields were reduced to $42\~63\%$ by the infection of late blight and the reduction rate was closely related with the time of first occurrence of the disease in organic farming fields. Physiological races of the pathogen were diversified with R0,1,3,4,5,7,10,11 in organic farming fields at Hongchun area. Pathogen races were distributed with similar pattern at different areas of organic farming fields.

• Journal of Practical Agriculture & Fisheries Research
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• v.4 no.1
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• pp.45-54
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• 2002

A lot of clones of the genus Dioscorea species have been introduced from some tropical and subtropical regions since 1997. The aim of this study was to determine characteristics of the production process in yams(Dioscorea spp). By utilizing 51clones of water yams(Dioscorea spp), some morphological characteristics were investigated at the field. Intraspecific genetic relationship of 51 variation types of the Yam classified by their external morphological characteristics such as leaf and tuber shape were assessed by DNA using random and specific primers. D. Alata and D. opposita were showed different relationship between yield and the growth of their aboveground parts. This suggests that even in the same species there were differences in yield volume and translocation of assimilation products, depending on the types. D. alata were distinguished from others Dioscorea species at 62% level in AFLP analysis. Also in principal component analysis, D. alata were showed the class from II to V.