• Journal of Distribution Science
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• v.14 no.7
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• pp.53-61
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• 2016

Purpose - The production efficiency of agricultural crops has been the subject of numerous studies in the field of agricultural economics. This study examines the production efficiency of emerging vineyards in the 14 northern U.S. states and aims to understand raw input and managerial factors affecting the grape production with focusing on the effect of farm size. Research design, data, and methodology - Using a unique survey dataset that was collected from 176 vineyards in 2012, we employed data envelopment analysis (DEA) for estimation of production efficiency in individual vineyards. Production efficiency is regressed on various input and managerial covariates to understand factors influencing the productivity. Results - Although there exists positive correlation between the farm size and productivity of vineyards in Northern U.S. states, we find negative relationship when the farm size is instrumented by the additional farm size expansion indicator. The negative effect is more pronounced for the recently established vineyards. Conclusions - This study suggests that there needs to be adequate managerial improvements for emerging vineyards in northern states for the achievement of increased productivity.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.771-776
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• 1999

RUSLE was applied to estimate annual soil loss from two small agricultural watersheds in Kangwon-do, Korea. GIS input parameters were prepared by using DEMs and soil maps prepared by the NGIS project and Rural Development Adminstration, respoctively. RUSLE parameters were prepared based on existing data and equations. Estimated annual soil loss was graphically presented to easily visualize the large soil loss area. Uplands and vineyards proved to be the two greatest sources for soil erosion. It was suggested to develop effective management practices to reduce the soil erosion from uplands and vineyards.

• Korean Journal of Environmental Agriculture
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• v.33 no.3
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• pp.178-183
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• 2014

BACKGROUND: The white stain symptom of grape clusters and canes by dust-like particles occurred in many vineyards recently. This study was conducted to investigate the ecological characteristics of white stain symptom in grapevines and vineyards. METHODS AND RESULTS: Optimal climate condition for white stain symptom was $25^{\circ}C{\sim}30^{\circ}C$ with 60% of humidity. Moreover, closed condition with same humidity showed higher incidence rate of white stain symptom than ventilation condition. Grape varieties with black berry skin such as Campbell-Early and Kyoho were more sensitive to white stain symptom compare to varieties with green and red berry skin. Although the pathogens were not detected until March, they increased from April, and increased sharply from mid of July. The pathogens may overwinter in the infected stems and/or on the bark as a mycelium. According to the increase of sugar content of grape from August to September, the mycelium which was parasitic on the bark grew to move to the fruits through the stems, and finally reached the fruit stalk to detach berries from the clusters. CONCLUSION: Well ventilation is recommended inside the vineyard since mid-July with roll up an insect net. In addition, infected stems and fruits should be removed out from grapevines infected with pathogens in the vineyards.

• The Plant Pathology Journal
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• v.35 no.2
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• pp.125-136
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• 2019

Vitis vinifera is very susceptible to downy mildew (Plasmopara viticola). A number of authors have suggested different genetic populations of this fungus exist in Europe, each showing a different degree of virulence. Work performed to date indicates this diversity to be the result of different factors. In areas where gene flow is greater and recombination more frequent, the diversity of P. viticola appears to be wider. In vineyards isolated by geographic barriers, a race may become dominant and produce clonal epidemics driven by asexual reproduction. The aim of the present work was to identify the conditions that influence the genetic diversity of P. viticola populations in the vineyards of northwestern Spain, where the climatic conditions for the growth of this fungus are very good. Vineyards situated in a closed, narrow valley of the interior, in more open valleys, and on the coast were sampled and the populations of P. viticola detected were differentiated at the molecular level through the examination of microsatellite markers. The populations of P. viticola represented in primary and secondary infections were investigated in the same way. The concentration of airborne sporangia in the vegetative cycle was also examined, as was the virulence of the different P. viticola populations detected. The epidemiological characteristics of the fungus differed depending on the degree of isolation of the vineyard, the airborne spore concentration, and on whether the attack was primary or secondary. Strong isolation was associated with the appearance of dominant fungal races and, therefore, reduced populational diversity.

• Journal of Bio-Environment Control
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• v.31 no.4
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• pp.356-365
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• 2022

Agrivoltaic systems, also called solar sharing, stated from an idea that utilizes sunlight above the light saturation point of crops for power generation using solar panels. The agrivoltaic systems are expected to reduce the incident solar radiation, the consequent surface cooling effect, and evapotranspiration, and bring additional income to farms through solar power generation by combining crops with solar photovoltaics. In this study, to evaluate if agrivoltaic systems are suitable for viticulture, we investigated the microclimatic change, the growth of vines and the characteristics of grape grown under solar panels set by planting lines compared with ones in open vineyards. There was high reduction of wind speed during over-wintering season, and low soil temperature under solar panel compared to those in the open field. There was not significant difference in total carbohydrates and bud burst in bearing mother branches between plots. Despite high content of chlorophyll in vines grown under panels, there is no significant difference in shoot growth of vines, berry weight, cluster weight, total soluble solid content and acidity of berries, and anthocyanin content of berry skins in harvested grapes in vineyards under panels and open vineyards. It was observed that harvesting season was delayed by 7-10 days due to late skin coloration in grapes grown in vineyards under panels compared to ones grown in open vineyards. The results from this study would be used as data required in development of viticulture system under panel in the future and further study for evaluating the influence of agrivoltaic system on production of crops including grapes.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2005.09a
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• pp.208-211
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• 2005

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.347-355
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• 2009

Grape fruit quality can be deteriorated with leaf chlorosis caused by magnesium (Mg) deficiency during fruit coloring season in several grapevine varieties. The occurrence of leaf chlorosis and soil Mg states for four grapevine varieties (Campbell Early, Muscat bailey A (MBA), Sheridan, and Kyoho) in the vineyards of Gyeongsan and Youngcheon were surveyed. The relationships between leaf chlorosis and fruit qualities were also investigated. Leaf chlorosis was more widely found and the symptom was stronger in Campbell Early in comparison to the other varieties. Sugar content and Hunter values (L, a, b) of grape fruit were significantly lower in the trees of chlorosis when compare to healthy grapevine trees. Soil Mg contents in the vineyards where leaf chlorosis was found were lower than the optimum level for grapevine. Also Mg content in the petioles of chlorosis grapevines was significantly lower than healthy grapevines. Application of Mg through foliar spray and soil fertigation was quite effective in correcting deficiencies of Mg in grapevine. Proper management of soil Mg availability and K/Mg ratio is strongly recommended to prevent Mg deficiency in grapevine.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.3
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• pp.187-191
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• 2009

'Campbell Early', a major grape cultivar, occupies more than 70% of cultivated vineyard areas, however, recommendable standard management system of soil environmental conditions has not been developed yet in Korea. The consideration for the correlation between fruit quality and soil condition in the vineyard is required in the efficient management system of soil. This study was carried out to investigate the optimum soil environmental conditions for 'Campbell Early' grape production with high quality. The results from analyses of correlation between them were used to develop soil management guideline for promoting efficiency in grape production. Soil properties were analyzed from 120 vineyards in Hawsung, Sangju, Yeongdong, Gimcheon, Yeongju, and Yeongwol, major grape production regions. Because there is neither coloring disorder nor delayed coloration in grape production of 'Campbell Early', relative contribution of soil hardness and solid phase to fruit quality and fruit weight was analyzed. Among the soil properties, while cation and soil hardness affected sugar content at the level of 39.3% and 36.8%, respectively, saturated hydraulic conductivity, solid phase, and cation exchange capacity (CEC) showed relatively low contribution to sugar content in the vineyard. The sugar content in grapes was influenced more critically by the chemical properties than the physical ones in the soil of vineyards. While soil hardness and solid phase affected grape weight at the level of 27.8% and 26.0%, respectively, phosphate content, organic matter content, and cation showed low contribution to grape weight. Grape guality such as sugar content and grape weight was affected highly by cation and organic matters. Therefore, cation and organic matter content of soil contributed to fruit quality at the level of 33.8% and 15.5%, respectively, in the vineyard.

• Research in Plant Disease
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• v.14 no.2
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• pp.90-94
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• 2008

To investigate the severity of crown gall disease on grapevine, the ratio of healthy vs. galled grapevines and the presence of the pathogen of the disease in soil were measured in Korean vineyards. In field and greenhouse cultivations, the crown gall incidence of the cv. Kyoho grapevines was $0.4{\sim}97.9%$ and $1.4{\sim}3.8%$ and those of cv. Campbell Early was $1.2{\sim}2.1%$ and $0{\sim}1.8%$, respectively. The higher populations of Agrobacterium spp. were isolated from soils of grapeveins with crown gall than from soils of noninfected vineyards. Based on the colony shapes and growth on plates, 480 isolates of Agrobacterium spp. from 21 soil samples were collected. Only 13 isolates out of 480 developed the gall on inoculated grapevines.

• Korean Journal Plant Pathology
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• v.12 no.3
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• pp.316-323
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• 1996

비가림재배 포도원에서 발생하는 흰가루병에 대하여 triazole계 살균제 flusilazole, myclobutanil, difenoconazole, penconazole, triflumizole, triadimefon의 방제 효과를 검정한 결과는 다음과 같다. 살균제 처리구의 이병과방율과 이병엽율은 무처리구에 비해 현저히 감소하였고, 이들의 방제가는 과방에서 약제에 따라 94.7∼97.9%, 잎에서 85.5%∼90.9%였으며 대조약제인 polyoxin B의 방제가와 유사한 정도를 보였다. 공시살균제의 보호효과는 살균제를 병발생 1주일전에 살포하는 경우, 살포 3주 후에 방제가는 약제에 따라 72.2∼90.5%였으나 4주 후에는 21.2∼41.6%로 감소하여 대조약제 polyoxin B의 52.5%보다 감소시켰으나 myclobutanil의 발아억제 효과는 약제 농도증가에 크게 영향받지 않았다. 살균제에 침지한 cheesecloth를 포도원 선반에 매달아 조사한 공시살균제의 훈증효과는 살포농도의 2배로 처리했을 때 처리점으로부터 반경 30cm이내의 포도송이에서는 약제에 따라 57.2∼71.1%의 방제가를 보였으나 전체 식물체에서는 49.1∼65.8%로서 10일 간격으로 3회 살포한 것 보다 낮은 방제가를 보였다.