• Food Science and Preservation
• /
• v.16 no.4
• /
• pp.490-498
• /
• 2009

This study attempted to examine the profitability and marketing costs of seed potato under contract farming system of BADC (Bangladesh Agricultural Development Corporation) with the help of primary and secondary data. Total 45 contract farmers were randomly selected. Attempts were made to calculate costs, returns and profitability of seed potato production under contract farming system, and to identify marketing channels of seed potato. The field level data were collected by a farm survey during the months of April 2005 through direct interviews with contract farmers and registered dealers using a structure survey questionnaire. The results showed that the gross return per hectare was Tk. 252,464 for all categories of farms. Cost of seeds, fertilizers, pesticides, irrigation and human labor were critical inputs for profitability of seed potato. Cobb-Douglas production function analysis was used to determine the effects of the key variables to seed potato production under contract farming system. The elasticity of seed potato production was at 0.727 for all categories of farms. The findings exhibited that the summation of elasticity of different inputs for seed potato production was less than one, implying that the production function exhibited decreasing returns to scale. Registered dealers and Upazila Sales Centers were involved in seed potato marketing formed a straightforward marketing channel. The total marketing costs of registered dealers were Tk. 759.49 per ton of seed potato. The net marketing margin of registered dealers was estimated at Tk. 465.51 per ton of seed potato. The selected contract farmers and registered dealers faced a number of problems and some of recommendations were suggested.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.23 no.4
• /
• pp.412-420
• /
• 2013

Objectives: This study was conducted in order to evaluate personal and area exposure to airborne total dust and endotoxin during harvest and planting tasks at cucumber, yellow melon and potato farms Materials and Methods: Total dust was measured with NIOSH method 0500. Endotoxin were measured using a 37 mm glass fiber filter which was connected to an air pump calibrated to 2 LPM, and then analyzed with a Turbidmetric kinetic method. Results: The average(arithmetic mean) concentrations of total dust in the personal samples were $0.10-3.81mg/m^3$ for cucumbers, $0.21-1.19mg/m^3$ for yellow melon, and $0.08-2.72mg/m^3$ for potato. There was a significant difference in the harvest task among the three farm types(p=0.019 of personal sample, p=0.048 of area sample), in which the air concentration for potatoes was higher than with cucumbers and yellow melons. Conclusions: It was found that potatoes(planting and harvest) should be considered the first priority for studying and reducing total dust exposure.

• Journal of Biosystems Engineering
• /
• v.42 no.3
• /
• pp.147-154
• /
• 2017

Purpose: To reduce the costs of potato seeds and labor of workers, a fully automatic in-situ seeding machine for cutting seed potatoes was developed. Methods: An experiment was conducted to evaluate the seeder performance of the prototype of potato planter by cutting seeds in farmlands from March to April 2017. The study tested the seeder performance at working speeds ranging from 0.28 to 0.45 m/s. The seeding rate and seeding distance were also investigated according to the planned distance between planted seeds from 20 to 30 cm, with 5 cm intervals. Results: Tests on the performance of the developed cutting blade on the automatic potato seeder show that whole potatoes should be used instead of half potatoes. The seeding rates were 88.8% and 82.5% for whole and half potatoes, respectively. When the tractor working speed was increased from 0.28 to 0.45 m/s, the successful seeding rate decreased from 98.8% to 96.3%, respectively. However, with planted seed distances of 20, 25, and 30 cm, the successful seeding rates were near 98%. Conclusions: The developed automatic potato seeder can to improve the labor productivity and cultivation environment of potato farms by the mechanization of the seeding process, which is currently associated with high-labor, -costs, and -hours. Therefore, based on this study, the developed automatic potato seeder provides the mechanization necessary for improved potato cultivation conditions in farmlands.

• Korean journal of applied entomology
• /
• v.13 no.1 s.18
• /
• pp.41-45
• /
• 1974

A total of 230 apparently healthy looking potato stocks and 80 potato stocks with symptoms of virus infection were collected from various seed potato farms in Korea and the incidence of potato virus X (PVX), potato virus S (PVS), potato virus M (PVM) and potato virus Y (PVY) was determined by serological microprecipitin tests. Results obtained are as follows. 1. Serological microprecipitin test retreated the presence of PVX, PVS, PVM and PVY in a number of potato stocks grown for the production of seed potatoes in Korea. 2. The occurrence of potato virus M is reported here for the first time in Korea with experimental evidence. 3. Practically $100\%$ (290 stocks, of the apparently healthy looking potato stocks were demonstrated to be infected with both PVX and PVS. The infection percentages of potato stocks with combination of PVX, PVS, PVM and PVY were as follows. PVX+PVS+PVM:$10.3\%$, PVX+PVS+PVY:$4.5\%$, PVX+PVS+PVM+PVY:$1.03\%$ 4. Irish Cobbler and Shimabara, which are the two major potato varieties in Korea, appear to be symptomless carriers of PVX and PVS. However, when these varieties were infected additionally with PVY, usually severe symptoms resulted. 5. Serological microprecipitin technique appears to be highly suitable for early, quick and reliable diagnosis of PVX, PVS PVM and PVY. It is particularly suited for large scale testing of seed potato stocks for the presence of viruses mentioned above.

• Research in Plant Disease
• /
• v.29 no.2
• /
• pp.130-136
• /
• 2023

Citrus melanoses caused by Diaporthe citri, has been one of the serious diseases in many citrus orchards of Jeju Island. To protect melanose in citrus farms, a fast and exact diagnosis method is necessary. In this study, diseased leaves and dieback twigs were collected from a total of 49 farms within March to April in 2022. A total of 465 fungal isolates were obtained from a total of 358 isolated plant samples. Among these fungal isolates, 40 representatives of D. citri isolates which were isolated from 22 twigs and 18 leaves on 23 farms were found based on cultural characteristics on potato dextrose agar and conidial morphology. Additionally, the molecular assay was carried out and compared with those by morphological diagnosis. All isolates were identified as D. citri by analyzing the sequences at the internal transcribed spacer (ITS) rDNA region using primers of ITS1/ITS4 or at β-tubulin using primer Btdcitri-F/R. Therefore, based on the present study, where the results of morphological identification of conidial type were consistent with DNA sequence analysis of certain gene, choosing a suitable method for a fast diagnosis of citrus melanose was suggested.

• Journal of the Economic Geographical Society of Korea
• /
• v.25 no.4
• /
• pp.451-468
• /
• 2022

Leading enterprises in contract farming are in control of agricultural production and influence the structure of the agricultural system in contract areas. This study focuses on the contract farming of potatoes for manufacturing chips, which uses a high proportion of domestic raw materials, and identifies the characteristics of contract farming between confectionery company 𐩒 and potato farms in Haean-myeon, Yanggu-gun, Gangwon-do. This study also analyzes the impact of contract farming on local agriculture from the perspective of the industrialization of agriculture. The results of this study demonstrated that contracting companies ensured the quality of potatoes and smooth agricultural operations by first preferentially selecting farmhouses with land that is easy to work with and then supplying the necessary agricultural machinery to promote the intensification of their work. In addition, contracting companies influenced the centralization of the agriculture sector by selecting farmhouses capable of contracting over a certain scale and guaranteeing them sales channels and the specialization of potato farming in contract areas, mainly through the supply of processing varieties and the spread of cultivation technology. The results confirmed that these three dimensions of contract farming promoted the industrialization of local agriculture.

• Research in Plant Disease
• /
• v.29 no.4
• /
• pp.399-404
• /
• 2023

Agricultural activities and the number of farms in the subarctic regions have been increasing annually after the coronavirus disease 2019 pandemic to achieve food self-sufficiency. Potatoes are vulnerable to soft rot bacteria at all stages of production, storage, and transportation. A novel bacterium, Pseudomonas sp. N3-W, isolated from Alaska tundra soil, grows at 5-25℃ and produces extracellular protease(s). N3-W caused necrotic spots (hypersensitivity) in hot pepper leaves and soft rot disease (pathogenicity) in potato tubers. The psychrotolerant N3-W caused significant soft rot symptoms on potatoes at a broad temperature range (5℃, 15℃, and 25℃). In contrast, mesophilic Pectobacterium carotovorum KACC 16999 induced severe rotting symptoms in potatoes at their optimal growth temperature of 15℃ and 25℃. However, it barely produced symptoms at 5℃, which is the appropriate storage and transportation temperature for potatoes. The results of pathogenicity testing imply that psychrotolerant soft rot pathogens from polar regions may cause severe soft rot not only during the crop growing season but also during storage and transportation. Our study indicates the possibility of new plant pathogen emergence and transmission due to the expansion of crop cultivation areas caused by permafrost thawing in response to recent polar warming.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.67 no.3
• /
• pp.172-179
• /
• 2022

Sweet potato varieties with high fiber content in the storage root have poor texture when steamed or roasted. This study investigates the difference in fiber content among sweet potato varieties by soil and climate. The average fiber content of 'Hogammi', 'Sodammi', 'Pungwonmi', 'Danjami', and 'Jinyulmi' cultivars from the samples collected at farms in Haenam, Muan, and Unbong, Korea were 95.71, 66.73, 44.55, 40.55, and 38.53 mg/100g FW, respectively. There was no significant difference between site-specific conditions and varieties. Based on the degree of visual fibrousness, 'Hogammi' has an average of 3.6-4.0 with many thick stringy fibers. The fiber content of the 'Hogammi' cultivar was measured across 19 sites representing the main sweet potato growing regions of Korea. The fiber content was between 115.82 and 114.6 mg/100g in Haenam 2 and Boryeong 1, and 87.46 mg/100g in Hamyang. However, the fiber content at the remaining 16 sites was within the range of 94.63-108.52 mg/100g, although there were some site-level differences. The fiber content of the sweet potato storage roots were positively correlated with soil phosphorus (R² = 0.58^**), organic matter (R² = 0.52^*), and pH (R² = 0.51^*), which had a significance of 1% and 5%. The fiber content of sweet potato storage roots was found to have increased with increasing phosphorus content, organic matter and pH in the soil. However, there was no correlation with the amount of precipitation, days of precipitation and hours of sunshine with the fiber content of sweet potato at the selected sites.

• Korean journal of applied entomology
• /
• v.9 no.1
• /
• pp.43-48
• /
• 1970

To investigate provincial seed Potato Production farms, a Preliminary survey on the local population of the aphids was made in Sulchon alphine area, Mooju-Goon, Chollapuk-Bo where the climatic conditions were almost same as those of Taegwanryong Kangwon-Do, where Alpine Experimental station is located. This area stands from 650 to 900 metres above the sea level and divided three location of A. B, C, by altitude. A stands at 900 metres above the sea level. B at 750 metres and C at 650 metres. A and B divided three points: Al, A2, A3, and Bl, B2, B3- and divided four points-Cl, C2, C3, C4- at the distance of 300 metres apart each other. The traps were operated from July 21 to October 31, 1969. Otherwise, the traps established at Suwon (inland) and Taegwanryong where Alpine Experimental Station. A total of some 70 species including five virus vector species were identified. The Numbers of species at 10 locations, Suwon and Taegwanryong are as follows; Al-34, A2-38, A3-29, B1-25, B2-26, B3-29, C1-27, C2-14, C3-32, C4-37, species (Table 1), Suwon-49 species (including 5 virus vectors species), Taegwanryong-22 species (including 4 virus vector species). The aphids are shown in Table 1 and the Vectors are as follows: 1. Aphis gossypii Glover 2. Aulacorthum solani (Kaltenbach) 3. Lipaphis erysimi (Kaltenbach) 4. Myzus persicae(Sulzer) 5. Phorodon humuli (Schrank) Numbers of vectors versus total aphid at each locations, including inland (Suwon) and alpine area (Taegwanryong) where Alpine Experimental Station are as Fig. 1. Of a total 8,902 aphids, 6,400 $(80\%)$ were Tetraneura sp. The number of aphids devoid of the number of Tetraneura sp. are as follows; (Numbers means mean of each locations) A; 215. B; 115, C; 176 and Suwon; 2,952, Taegwanryong; 247. Densities of aphids at the locations is lower :han those at Suwon and Taegwanryong. And density of vectors at the locations, at ranged from 11 to 37, is love. than those at inland (Suwon; 197) and alpine area (Taegwanryong; 90). Thus, this area is suitable for seed potato production as Multiplication field.

• Korean Journal of Environmental Agriculture
• /
• v.22 no.4
• /
• pp.261-265
• /
• 2003

In order to examine the difference in processing quality of potato tubers among localities, chemical properties of soils were analyzed and climatic conditions were investigated. Potatoes (Solanum tuberosum L.) were grown at seven localities of Korea during two years from 1994 to 1995. Soil samples and tubers were obtained from 2 to 3 commercial farms per locality with 10 days interval from 70 days before harvesting. As the result of that, higher correlation in processing quality was found with organic material content among soil conditions. On the climatic conditions, minimum temperature and sunshine hours during the period from 30 to 11 days before harvesting exhibited highly significant negative correlations with all quality parameters except reducing sugar content. Additionally, regression equations based on the observed level of these factors showed the relatively high coefficients of determination for dry matter content and chip color. To produce higher quality potatoes for processing, therefore, climatic conditions such as minimum temperature and sunshine hour and soil condition such as organic matter content have to be considered before the selection of areas or fields.