• Title/Summary/Keyword: Cool-season turfgrass

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Comparison of Underground Root Growth Characteristics of Major Cool-Season Grasses according to Establishment Stages in Sports Turf Designed by the USGA Soil System (USGA 지반으로 설계된 스포츠 잔디밭에서 조성단계별 주요 한지형 잔디의 지하부 뿌리생육 특성 비교)

  • Kim, Kyoung-Nam
    • Horticultural Science & Technology
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    • v.33 no.2
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    • pp.166-176
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    • 2015
  • Research was initiated to investigate root growth characteristics of major cool-season grasses (CSG) and to collect basic information useful for sports turf design, construction and maintenance. Several turfgrasses were evaluated in the USGA (United States Golf Association) soil system. Turfgrass entries were comprised 3 blends and 3 mixtures of Kentucky bluegrass (KB, Poa pratensis L.), perennial ryegrass (PR, Lolium perenne L.), and tall fescue (TF, Festuca arundinacea Schreb.). Significant differences were found in root growth, rooting potential and rooting development. These characteristics increased with time after seeding, but varied with establishment stages. In early stage, root length was highest with PR, intermediate with TF and lowest with KB. Evaluation in a middle stage indicated that root growth was similar to early-stage evaluation, but decreased by 13 to 31% compared with early-stage values. Root growth of late stage increased by 34 to 85% over middle-stage root growth. Overall, thhere was not much difference in root length among treatments, with all except Mixture I reaching 22cm in root length. Rooting potential ranking was variable with establishment stage, being PR > KB > TF in early stage, PR > TF > KB in middle stage and TF > PR > KB in late stage. At the end of the study, TF was rated best for rooting development, followed by PR and finally KB. Our results showed that TF was the best species in regard to overall rooting characteristics. TF exhibited excellent rooting development with time after establishment. Bunch-type PR showed fast root growth in the early stage, but rooting quality characteristics decreased with time, especially for rooting development. By contrast, rhizomatous-type KB was poor in early-stage root growth, but rooting characteristics improved with time after establishment. These variations in rooting characteristics among CSGs were considered to arise from differences in establishment vigor, growth habit and genetic characteristics. Information on root growth, rooting potential and rooting development by establishment stages will be useful for sports turf design, construction and maintenance.

Comparison of Early Germinating Vigor, Germination Speed and Germination Rate of Varieties in Poa pratensis L., Lolium perenne L. and Festuca arundinacea Schreb. Grown Under Different Growing Conditions (생육환경에 따른 Poa pratensis L., Lolium perenne L. 및 Festuca arundinacea Schreb.의 초종 및 품종별 발아세, 발아속도 및 발아율 비교)

  • 김경남;남상용
    • Asian Journal of Turfgrass Science
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    • v.17 no.1
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    • pp.1-12
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    • 2003
  • Research was Initiated to investigate germination characteristics of cool-season grasses (CSG). Several turfgrasses were tested in different experiments. Experiments I and III were conducted under a room temperature condition of 16$^{\circ}C$ to 23 $^{\circ}C$ and under a constant light condition at 25 $^{\circ}C$, respectively. An alternative environment condition that is a requirement for a CSG germination test by International Seed Testing Association (ISTA) was applied in the Experiment II, consisting of 8-hr light at 25 $^{\circ}C$ and 16-hr dark at 15 $^{\circ}C$. In each experiment, data such as early germinating vigor, germination speed and germination rate were evaluated. Six turfgrass entries were comprised of two varieties each from Kentucky bluegrass (KB, Poa pratensis L.), perennial ryegrass (PR, Lolium perenne L.), and tall fescue (TF, Festuca arundinacea Schreb.), respectively. Significant differences were observed in early germinating vigor, germination speed and germination rate. Early germinating vigor as measured by days to 70% seed germination was variable according to environment conditions, turfgrasses and varieties. It was less than 6 days in PR and 6 to 9 days in TF. However, KB resulted in 11 to 13 days under an alternative condition and 11 to 28 days under a room temperature condition. The germination speed was fastest in PR of 7 to 10 days and slowest in KB of 14 to 21 days. However, intermediate speed of 10 to 14 days was associated with TF. There were considerable variations in germination rate among turfgrasses according to different conditions. Generally, PR and TF germinated well, regardless of environment conditions. However, a great difference was observed among KB varieties, when compared with others. Under a room temperature condition, total germination rate was 71.0% in Midnight and 77.7% in Award. And it increased under an alternative condition, which was 81.7% and 91.7% in Award and Midnight, respectively. However, the poorest rate was found under a constant temperature condition, resulting in 18.0% in Award and 15.3% in Midnight. These results suggest that an intensive germination test required by ISTA be needed prior to the decision of seeding rate, including early germinating vigor and germination speed as well as total germination rate. KB is very sensitive to environment conditions and thus its variety selection should be based on a careful expertise.

Herbicidal Phytotoxicity under Adverse Environments and Countermeasures (불량환경하(不良環境下)에서의 제초제(除草劑) 약해(藥害)와 경감기술(輕減技術))

  • Kwon, Y.W.;Hwang, H.S.;Kang, B.H.
    • Korean Journal of Weed Science
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    • v.13 no.4
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    • pp.210-233
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    • 1993
  • The herbicide has become indispensable as much as nitrogen fertilizer in Korean agriculture from 1970 onwards. It is estimated that in 1991 more than 40 herbicides were registered for rice crop and treated to an area 1.41 times the rice acreage ; more than 30 herbicides were registered for field crops and treated to 89% of the crop area ; the treatment acreage of 3 non-selective foliar-applied herbicides reached 2,555 thousand hectares. During the last 25 years herbicides have benefited the Korean farmers substantially in labor, cost and time of farming. Any herbicide which causes crop injury in ordinary uses is not allowed to register in most country. Herbicides, however, can cause crop injury more or less when they are misused, abused or used under adverse environments. The herbicide use more than 100% of crop acreage means an increased probability of which herbicides are used wrong or under adverse situation. This is true as evidenced by that about 25% of farmers have experienced the herbicide caused crop injury more than once during last 10 years on authors' nationwide surveys in 1992 and 1993 ; one-half of the injury incidences were with crop yield loss greater than 10%. Crop injury caused by herbicide had not occurred to a serious extent in the 1960s when the herbicides fewer than 5 were used by farmers to the field less than 12% of total acreage. Farmers ascribed about 53% of the herbicidal injury incidences at their fields to their misuses such as overdose, careless or improper application, off-time application or wrong choice of the herbicide, etc. While 47% of the incidences were mainly due to adverse natural conditions. Such misuses can be reduced to a minimum through enhanced education/extension services for right uses and, although undesirable, increased farmers' experiences of phytotoxicity. The most difficult primary problem arises from lack of countermeasures for farmers to cope with various adverse environmental conditions. At present almost all the herbicides have"Do not use!" instructions on label to avoid crop injury under adverse environments. These "Do not use!" situations Include sandy, highly percolating, or infertile soils, cool water gushing paddy, poorly draining paddy, terraced paddy, too wet or dry soils, days of abnormally cool or high air temperature, etc. Meanwhile, the cultivated lands are under poor conditions : the average organic matter content ranges 2.5 to 2.8% in paddy soil and 2.0 to 2.6% in upland soil ; the canon exchange capacity ranges 8 to 12 m.e. ; approximately 43% of paddy and 56% of upland are of sandy to sandy gravel soil ; only 42% of paddy and 16% of upland fields are on flat land. The present situation would mean that about 40 to 50% of soil applied herbicides are used on the field where the label instructs "Do not use!". Yet no positive effort has been made for 25 years long by government or companies to develop countermeasures. It is a really sophisticated social problem. In the 1960s and 1970s a subside program to incoporate hillside red clayish soil into sandy paddy as well as campaign for increased application of compost to the field had been operating. Yet majority of the sandy soils remains sandy and the program and campaign had been stopped. With regard to this sandy soil problem the authors have developed a method of "split application of a herbicide onto sandy soil field". A model case study has been carried out with success and is introduced with key procedure in this paper. Climate is variable in its nature. Among the climatic components sudden fall or rise in temperature is hardly avoidable for a crop plant. Our spring air temperature fluctuates so much ; for example, the daily mean air temperature of Inchon city varied from 6.31 to $16.81^{\circ}C$ on April 20, early seeding time of crops, within${\times}$2Sd range of 30 year records. Seeding early in season means an increased liability to phytotoxicity, and this will be more evident in direct water-seeding of rice. About 20% of farmers depend on the cold underground-water pumped for rice irrigation. If the well is deep over 70m, the fresh water may be about $10^{\circ}C$ cold. The water should be warmed to about $20^{\circ}C$ before irrigation. This is not so practiced well by farmers. In addition to the forementioned adverse conditions there exist many other aspects to be amended. Among them the worst for liquid spray type herbicides is almost total lacking in proper knowledge of nozzle types and concern with even spray by the administrative, rural extension officers, company and farmers. Even not available in the market are the nozzles and sprayers appropriate for herbicides spray. Most people perceive all the pesticide sprayers same and concern much with the speed and easiness of spray, not with correct spray. There exist many points to be improved to minimize herbicidal phytotoxicity in Korea and many ways to achieve the goal. First of all it is suggested that 1) the present evaluation of a new herbicide at standard and double doses in registration trials is to be an evaluation for standard, double and triple doses to exploit the response slope in making decision for approval and recommendation of different dose for different situation on label, 2) the government is to recognize the facts and nature of the present problem to correct the present misperceptions and to develop an appropriate national program for improvement of soil conditions, spray equipment, extention manpower and services, 3) the researchers are to enhance researches on the countermeasures and 4) the herbicide makers/dealers are to correct their misperceptions and policy for sales, to develop database on the detailed use conditions of consumer one by one and to serve the consumers with direct counsel based on the database.

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