• Research in Plant Disease
• /
• v.12 no.3
• /
• pp.235-239
• /
• 2006

Since the cultivation of resistance cultivar is essential for organic agriculture, Phytophthora late blight resistance of 16 advanced potato clones obtained from the potato breeding laboratory at the National Institute of Highland Agriculture was evaluated. Resistance of the clone was examined through artificial inoculation in the laboratory and in the field. Dominant isolates of the pathogen in Gangwon province produced abundant sporangia on leaves of most clones showing susceptibility. The number of sporangia ranged from $10^{7{\sim}8}sporangia/ml$ in the susceptible clones at 7 days after inoculation. However, one clone is resistant in organic farming fields. Disease incidence was 2.3% using the resistant clone. The area under disease progress curve(AUDPC) was 75.5. Contrarily, disease incidence of the susceptible variety was 100% and the AUDPC was 1773.5 during the same cultivation period. The resistance clone named as 'Haryeong' is considered suitable for organic potato cultivation in Gangwon province in Korea.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.5
• /
• pp.564-569
• /
• 2015

In highland crop fields, saprolite is piled up approximately every three years as deep much as 20 to 30 cm because farmers expect that adding new materials may improve productivity and mitigate hazards by continuous cultivation of a single crop. Piling saprolite, however, has been reported to induce poor soil drainage. Effects of deep ploughing with a spading machine and an excavator were studied in sites located in Daekwanryeong-myeon, Pyeongchang in which soil physical properties were deteriorated by piled saprolite. The soil made of parent material of Samgag series was piled up over surface soil of Haggog series naturally developed in the area. Carrot was cultivated in the field. Productivity and growth factors of carrot were compared among control and deep ploughing by a spading machine and an excavator. Effective soil depth extended to 60 cm or greater by 60 cm deep ploughing by an excavator or 50 cm deep ploughing by a spading machine. On the other hand, effective soil depth was within 50 cm at control plot. Productivity of carrot responded to amelioration of soil physical properties. The productivity was greater in deep ploughing treatments than that of control or 30 cm ploughing. It suggested that increased productivity by deep ploughing was mainly related to breaking plough pan which inhibited extension of rooting zone.

• Korean Journal of Environmental Agriculture
• /
• v.24 no.1
• /
• pp.29-33
• /
• 2005

To develop proper soil management practices for reducing soil erosion, experiments were carried out by using lysimeters in Pyeongchang highland, Korea. Lysimeters installed at Hoenggye bad 13% slope, 15 m slope length and 3 m width. Lysimeters with 23% slope, 15 m slope length and 3 m width were also installed at Yongsan. Soil textures in Hoenggye and Yongsan lysimeter plots were silty clay loam and sandy loam, respectively. In the lysimeters potato was cultivated, and slant furrow culture and contour culture were applied. Up-down furrow and continuous fallow lysimeter was included in the experiments as a control plot. For the slant furrow and contour culture methods, minimum furrow mulching and gravel barrier were placed at each end of the furrows in the lysimeters from April to October in 2000 and 2001 to prevent soil and nutrient losses. In Heonggye, in two years experiments, average soil loss of 17 Mg/ha was found in the up-down and continuous fallow lysimeter and 2.6 Mg/ha from furrow minimum straw and slant furrow treatment, and 1.8 Mg/ha from slant furrow and gravel bag treatment. In the contour culture, the soil losses were further reduced. In Yongsan, soil loss in the slant furrow culture without any protection treatment was 167 Mg/ha, and the soil loss was reduce to 61 and 86 Mg/ha with minimum straw and gravel bag treatments, respectively. The soil loss could be reduced more than 45% by furrow minimum straw and gravel barrier. The furrow minimum straw or gravel bag barrier successfully reduced soil loss in clay loam soil in Heonggye, but still the treatments were not enough to reduce soil loss in saprolite piled sandy loam soil in Yongsan.

• Korean journal of applied entomology
• /
• v.47 no.4
• /
• pp.401-405
• /
• 2008

This study was conducted to estimate the control thresholds (CTs) of imported cabbage worm, Artogeia rapae L., injuring Chinese cabbage. The second instar larvae of A. rapae were inoculated with five density levels on each Chinese cabbages transplanted three weeks earlier under greenhouse condition, and checked injury rates after allowing their feeding for one week and two weeks, respectively. The average leaf area consumed by single larvae was 657.7 $mm^2$ in plots inoculated at three weeks after transplanting (WAT) and 2495.8 $mm^2$ in plots at 6-WAT, respectively. In the field experiment, different numbers of A. rapae ranged from one to seven larvae were inoculated on 20 plants. The percent yield reduction (Y) of Chinese cabbage infested by different densities of A. rapae (X) for a three-week period was estimated by the following equation; (1) Y=1.764X-0.3049 ($R^2$=0.9901) in plots inoculated at 3-WAT; and (2) Y=1.0305X-0.2976 ($R^2$=0.9398) in plots inoculated at 6-WAT. Based on the relationships between the densities of A. rapae larvae and the yield index of Chinese cabbage, the number of second instar larvae which caused 5% loss of yield (gain threshold proposed by Japan), was estimated as 3.0 per 20 plants for the 3-WAT and 5.1 for the 6-WAT.

• Korean Journal of Environmental Biology
• /
• v.29 no.4
• /
• pp.353-361
• /
• 2011

This study was conducted to examine the effects of sedimentation caused by highland agriculture on benthic macroinvertbrate assemblages in upper Song Stream from 2006 to 2009. The mean concentrations of water quality parameters (pH, DO, EC, TDS, TN, and TP) were gradually increasing toward downstream but ORP was decreased. Furthermore, biological habitats at lower reaches were more homogeneous and unstable due to sand deposition than those at upper sites. A total 106 species of benthic macroinvertbrates in 47 families, 11 orders, 6 classes, and 5 phyla were identified during whole field surveys. Song Stream showed great declines of overall biological attributes along its longitudinal gradients, particularly in taxa richness and abundance. Of all functional groups scrapers and clingers were most affected against the degradation of habitat quality, whereas collector-gatherers and burrowers showed the opposite case. It was found that such results had close correlations with water quality parameters and substrate composition which played an important role in structuring macroinvertebrate communities. In conclusion, this study represents that disturbance caused by highland agricultural activities had negative effects on benthic macroinvertebrate communities by leading to sand deposition at adjacent stream ecosystems.

• Korean Journal of Soil Science and Fertilizer
• /
• v.35 no.6
• /
• pp.372-380
• /
• 2002

This study was conducted to investigate the changes of soil properties for potato and Chinese cabbage after application adding phosphorus and potassium fertilizers in the mounded highland soil from 1999 to 2001. Experimental plots were designed with control(NPK+Lime+Compost) and chemical improvement(Control+Application adding P and K). Mounded soil before field experiment of first year(1999) was low in organic matter, available phosphorus and exchangeable potassium, and the soil texture was loamy sand soil. After 3 years, the contents of soil organic matter increased a little, and available phosphorus and exchangeable potassium contents were remarkably increased. The crop growth in chemical improvement plot was better than control plot. Yield of chemical improvement plot in comparison with control plot was increased by 5~22% for potato and 6~25% for Chinese cabbage after 2~3 years.

• Korean Journal of Plant Resources
• /
• v.34 no.4
• /
• pp.249-256
• /
• 2021

Napa cabbage (Brassica campestris var. Pekinensis) is the main material of Kimchi so that important crop in South Korea. There are two typical napa cabbage cropping systems in the alpine area. One is cultivating napa cabbage annually while another is cultivating napa cabbage and potato biennially. In this research, we evaluated soil physiochemical properties, yield, and mineral contents of napa cabbage depending on two cropping systems. As a result, organic matter, available P₂O₅, exchangeable K⁺ was decreased after six-years of cultivation on both cropping systems. However, soil pH was only decreased in a continuous napa cabbage cropping system. Soil porosity is also decreased in both cropping systems on topsoil while is increased in rotation with potato on subsoil. The rotation system showed a significantly higher yield with a higher value of leaf and napa cabbage size than the continuous cropping system. Total nitrogen, Ca²⁺, and Ma²⁺ were increased and total carbon and phosphate decreased in both cropping systems after six-years. Especially, total nitrogen and Mg²⁺ were significantly higher in the continuous system while Ca²⁺ was higher in the rotation system. In conclusion, the cropping system influences soil physiochemical properties and plant production in an agricultural field.

• Korean Journal of Plant Resources
• /
• v.30 no.4
• /
• pp.475-480
• /
• 2017

A new Gomchwi cultivar 'Damogy ' was bred by crossing between Gomchwi (Ligularia fischeri (Ledeb.) Turcz.) and Handaeri-gomchwi (Ligularia fischeri var. spiciformis Nakai). The selection and investigation of growth and yield characteristics were conducted from 2006 to 2011 in field and greenhouse of Highland Agriculture Research Institute, NICS, Rural Development Administration, Korea. On a newly developed cultivar 'Damogy', Color of petiole ear was purple, petiole trichome was exist, light of leaf back was not exist, and density of leaf vein was degree 4. Plant height, leaf length, leaf width and petiole length were 45.9, 16.9, 21.1 and 29.0 cm, respectively in the $3^{rd}$ year in growth characteristics. Plant size was also higher than that of Gondalbi. Bolting and flowering time were Aug. $23^{th}$ and Sept. $10^{th}$, respectively. In contrast, Gondalbi showed quite earlier bolting time more than 38 days compared with 'Damogy' and consequently earlier flowering time more than 26 day. 'Damogy' showed similar leaf number (129) per plant compared to 'Gondalbi' (130). Furthermore, yield was higher 'Damogy' (1,889 g/plant) than in 'Gondalbi' (798 g/plant). 'Damogy' showed higher leaf thickness (0.71 mm) than 'Gonalbi' (0.46 mm), and consequently showed more hardness in leaf characteristics ($28.3kg/cm^2$) compared with 'Gondalbi' ($23.0kg/cm^2$). 'Damogy' showed higher resistance in the susceptibility of powdery mildew disease compared to 'Gondalbi'. 'Damogy' variety was registered plant variety protection right as a No. 89 on December 2015.

• Korean Journal of Plant Resources
• /
• v.32 no.4
• /
• pp.338-343
• /
• 2019

This study was conducted to nominate optimal ground cover plants eventually enhancing Aronia production in the highland rolling plains. Total number of 17 weed species were observed in Aronia field when no cover plant was applied. Meanwhile, 12, 14, 15 and 16 weed species were observed when kentucky bluegrass, white clover, rattail fescue and ground ivy were used, respectively. Untreated native weed species were 73.6 cm tall before cut, and kentucky bluegrass, white clover, Rattail fescue and ground ivy were 57.5, 36.8, 48.3 and 40.9 cm, respectively. Based on plant height before cut, two shortest plants, white clover and ground ivy, were considered effective as ground cover plants in Aronia field. Coverage at $3^{rd}$ year by cover plants ranged from 85% to 100%. Coverage of uncovered Aronia field by native weed species was 95% while coverage by 4 treatments, kentucky bluegrass, white clover, rattail fescue and ground ivy were 100, 87, 85 and 100%, respectively. Aronia yield per plant at $3^{rd}$ year was 1,916 g with white clover cover followed by 1,770 g with Rattail fescue, 1,766 g with ground ivy, 1,098 g without cover plants and 931 g with Kentucky Bluegrass. Out results indicated that ground ivy was the best among all treatments based on 3 criteria, (1) short plant architecture, (2) rapid ground covering and (3) better weed control. In addition, ground ivy cover appeared to secure better yield.

• Journal of Korean Society on Water Environment
• /
• v.24 no.5
• /
• pp.569-580
• /
• 2008

In this study, area-weighted slope and slope length module, considering measured field slope and slope length of the agricultural fields within the subwatershed, was developed using the ArcView Avenue programming to reflect the field topography of the Soil and Water Assessment Tool (SWAT) HRU in simulating the hydrology and water quality. Flow and sediment yield estimated values of the SWAT were compared with and without applying area-weighted slope and slope length module, developed in this study. There was 103% increases in estimated sediment with area-weighted slope and slope length module for the study watershed. The soil erosion and sediment yield from only agricultural field in Hae-an watershed was also assessed. There are 111% increase in estimated soil erosion and 112% increase in estimated sediment by applying area-weighted slope and slope length module. This study shows that the area-weighted slope and slope length module needs to be utilized in estimating the HRU field slope and slope length for accurate estimation of soil erosion and nonponit source pollutant modeling with the SWAT although it is not feasible to measure topographic information for every agricultural fields within the watershed. The area-weighted slope and slope length module can be used in identifying soil erosion hot spot areas for developing cost effective and efficient soil erosion management practices.