Joon-Soo Choi

Effect of Turfgrasses to Prevent Soil Erosion

Recent climatic changes by global warming include increased amount and intensity of rainfall. This study was conducted to find out possible roles of turfgrasses to reduce the impact of climatic changes, especially surface soil erosion. Soil erosions by intensive rain were measured after each significant precipitation from the artificially sloped plots of zoysiagrass, cool-season grass mixture of Kentucky bluegrass and perennial ryegrass and other typical korean summer crops. Sodded zoysiagrass resulted in minimal annual soil erosion followed by stripsodded zoysiagrass and cool-season turfgrass mixture while dry-field rice and bean cultivations eroded the surface soils of 5 to 10 MT ㏊ -1 yr -1 and pepper cultivation resulted in 7 to 14 MT ㏊ - 1 yr -1 annual loss of surface soil. Annual loss of surface soil from bare land with hand weeding was up to 18 MT ㏊ -1 yr -1 while greatly reduced soil erosion was observed from weed grown treatment.

Growth of Zoysiagrass and Seashore Paspalum on Volcano Eruption Sand and Clayey Soil with Organic and Inorganic Fertilizers in Indonesia

This study was carried out to determine the possible use of volcano eruption sand at Merapi mountain area compared with clayey soil, alfisol as turfgrass growing media. Indonesia has abundant source of eruption sand and clayey soil. Native zoysiagrass (Z. matrella) was collected from Sleman district and seashore paspalum (P. vaginatum) from Solo region. The experimental plots were treated with both organic and inorganic fertilizers. Zoysiagrass and seashore paspalum can grow on the mixture of eruption volcano sand and alfisol soil. Fertilizers application increased turf color, surface coverage rate and recovery rate of turfgrass. While fertilizer treated alfisol have no effect on the length and dry weight of zoysiagrass root. Mixing of volcano eruption sand on growing media resulted in longer root length, higher shoot dry weight of zoysiagrass than in alfisol soil. Type of fertilizer affected the pH, soil organic matter, total N, available P, available K and electrical conductivity of sand and alfisol after cultivation. Similarly to zoysiagrass, the recovery of seashore paspalum was increased by application of fertilizer, even the inorganic fertilizer showed faster recovery than organic fertilizer. Surface coverage of seashore paspalum was faster than that of zoysiagrass with or without fertilizer.

RAPD-SCAR Markers Linked to Medium-Leaf Zoysiagrass Ecotypes

Two medium-leaf ecotypes (CY6069, CY6097) belonging to one species (Zoysia japonica) of Korean lawngrasses were selected in sod production fields in Jang Seong, Korea. They were reported to have distinct morphological and growth rate characteristics different from the preferred medium-leaf type zoysiagrass in Korea. This study was conducted to define further the genotypic difference at the molecular level and to develop DNA marker based on the specific DNA fragment. Polymorphic DNA fragments were first explored by using randomly amplified polymorphic DNA (RAPD) primers, which were then converted into PCR-based sequence characterized amplified region (SCAR) markers. The CY6069-specific primer set amplified about 550 bp successfully, while the CY6097 marker produced the expected 690 bp band, by which those markers were nominated by CY6069_550 and CY6069_690 SCARs, respectively. Together with the reported morphological and other phenotypic features, the SCAR markers confirmed in this study will be useful to identify those medium-leaf zoysiagrass genotypes when they are cultivated with other vegetatively propagated warm-season turfgrasses in sod farms.

Seed Yields and Germination Rates of Native Ecotype Collections for the Development of High-Yield Seeded Variety of Zoysiagrass in Korea

Seed Yields and Germination Rates of Native Ecotype Collections for the Development of High-Yield Seeded Variety of Zoysiagrass in Korea Eun-Ji Bae, Jeong-Ji Han, Su-Min Choi, Kwang-Soo Lee, Yong-Bae Park, Geun-Mo Yang, and Joon-Soo Choi * Southern Forest Resources Research Center, National Institute of Forest Science, Jinju 52817, Korea Department of Green Landscape Architecture Science, Dankook Univ., Cheonan 31116, Korea