Interpreting Soil Tests for Turfgrass

Nick E. Christians 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Development of Roundup Ready Bentgrass for the Control of Poa annua

Nick E. Christians(닉 크리스챤스),Jeong-Ho Lee(이정호) 한국잡초학회·한국잔디학회 2006 Weed & Turfgrass Science Vol.20 No.1

애뉴얼 블루그래스는 골프장에서 방제하기가 대단히 어려운 잡초이다. 방제가 어려운 이유로는 애뉴얼 블루그래스의 경우 불량환경에서도 왕성하게 종자생산을 할 수 있는 특성과 또한 낮은 예초환경에서도 적응력이 있기 때문이다. 하지만 무엇보다도 유전적으로 다양성이 있기 때문에 골프장의 잔디에 비해 우점할 수 있는 것이다. 일반적으로 애뉴얼 블루그래스는 일년생 한지형 잔디로, 생육형은 주형이다. 하지만 포복경이 있어 다년생의 특성을 갖는 생태형이 다른 애뉴얼 블루그래스도 있다. 골프장에서 애뉴얼 블루그래스 방제를 위해 화학적 방법과 재배적 방법에 관한 수많은 연구가 지난 85년간 진행되었다. 연구결과 일부 종류의 애뉴얼 블루그래스방제에 성공적인 결과도 있지만, 모든 종류의 애뉴얼 블루그래스 방제에 성공적인 방법은 아직 없는 실정이다. 이 모든 방제 방법들 중에 Roundup ready creeping bentgrass의 사용은 다양한 종류의 새포아풀을 방제 할 수 있다. Roundup readgy bentgrass는 Roundup에 내성이 있어 약해 피해 없이 생존이 가능하다. 따라서 골프장에서 이 새로운 기술을 활용하면 새포아풀이 없는 그린, 티, 훼어웨이를 유지할 수 있다. Annual bluegrass(Poa annua L.) is a problem weed that is very difficult to control on golf courses. There are some reasons that make Poa annua such a difficult weed to be controled. One of these reasons is this plant's ability to reproduce its seed even under stressful conditions. Another reason is its adaptation to low mowing heights. Above all things, the greatest competitive advantage of Poa annua is its genetic diversity. Generally, Poa annua is a bunch type and annual type cool-season grass, but some types act as weak perennials and have stolons. There has been much research on controlling annual bluegrass in golf course turf with chemical and cultural techniques. This research has been conducted for more than 85 years. There has been some progress in controlling some types of Poa annua, but these methods have not been successful on every biotype. Among all of the techniques, Roundup ready creeping bentgrass has the most promise of controlling the diverse types of Poa annua. Roundup ready bentgrass is capable of tolerating the effects of Roundup(glyphosate) while it kills other plants including Poa annua. By using this new technology, we can make Poa annua free greens, tees, and fairways.

Poa annua CONTROL

Nick Christians 한국잔디학회 2006 한국잔디학회 정기총회 및 학술발표회 Vol.19 No.-

ENVIRONMENTALLY SOUND TURFGRASS MANAGEMENT

닉 크리스챤(Nick Christians) 한국잡초학회·한국잔디학회 2005 Weed & Turfgrass Science Vol.19 No.2

Development of Roundup Ready Bentgrass for the Control of Poa annua

닉크리스챤스,이정호,Christians, Nick E.,Lee, Jeong-Ho Turfgrass Society of Korea 2006 한국잔디학회지 Vol.20 No.1

애뉴얼 블루그래스는 골프장에서 방제하기가 대단히 어려운 잡초이다. 방제가 어려운 이유로는 애뉴얼 블루그래스의 경우 불량환경에서도 왕성하게 종자생산을 할 수 있는 특성과 또한 낮은 예초환경에서도 적응력이 있기 때문이다. 하지만 무엇보다도 유전적으로 다양성이 있기 때문에 골프장의 잔디에 비해 우점할 수 있는 것이다. 일반적으로 애뉴얼 블루그래스는 일년생 한지형 잔디로, 생육형은 주형이다. 하지만 포복경이 있어 다년생의 특성을 갖는 생태형이 다른 애뉴얼 블루그래스도 있다. 골프장에서 애뉴얼 블루그래스 방제를 위해 화학적 방법과 재배적 방법에 관한 수많은 연구가 지난 85년간 진행되었다. 연구결과 일부 종류의 애뉴얼 블루그래스 방제에 성공적인 결과도 있지만, 모든 종류의 애뉴얼 블루그래스 방제에 성공적인 방법은 아직 없는 실정이다. 이 모든 방제 방법들 중에 Roundup ready creeping bentgrass의 사용은 다양한 종류의 새포아풀을 방제 할 수 있다. Roundup readgy bentgrass는 Roundup에 내성이 있어 약해 피해 없이 생존이 가능하다. 따라서 골프장에서 이 새로운 기술을 활용하면 새포아풀이 없는 그린, 티, 훼어웨이를 유지할 수 있다. Annual bluegrass(Poa annua L.) is a problem weed that is very difficult to control on golf courses. There are some reasons that make Poa annua such a difficult weed to be controled. One of these reasons is this plant's ability to reproduce its seed even under stressful conditions. Another reason is its adaptation to low mowing heights. Above all things, the greatest competitive advantage of Poa annua is its genetic diversity. Generally, Poa annua is a bunch type and annual type cool-season grass, but some types act as weak perennials and have stolons. There has been much research on controlling annual bluegrass in golf course turf with chemical and cultural techniques. This research has been conducted for more than 85 years. There has been some progress in controlling some types of Poa annua, but these methods have not been successful on every biotype. Among all of the techniques, Roundup ready creeping bentgrass has the most promise of controlling the diverse types of Poa annua. Roundup ready bentgrass is capable of tolerating the effects of Roundup(glyphosate) while it kills other plants including Poa annua. By using this new technology, we can make Poa annua free greens, tees, and fairways.

Environmentally Sound Turfgrass Management

닉 크리스찬,Christians Nick 한국잔디학회 2005 한국잔디학회지 Vol.19 No.2

Interpreting Soil Tests for Turfgrass

닉 크리스챤스,주영규,이정호,Christians, Nick,Joo, Young-Kyoo,Lee, Jeong-Ho Turfgrass Society of Korea 2006 한국잔디학회지 Vol.20 No.2

잔디 작물에 익숙하지 않은 토양 분석 실험실에서는 잔디 생육에 필요한 인에 대하여서는 과대평가를 하나, 칼륨에 대한 요구도는 대해서는 과소평가를 하는 경향이 있다. 그 이유는 부분적으로 잔디, 정원식물 및 농작물 사이에는 뿌리 발달의 차이가 있기 때문이다. 일반적으로 잔디는 토양으로부터 인을 흡수하는데 좀 더 효율적이기 때문에 인산질 비료에 대한 요구도가 적은 편이다. 작물 재배시에는 농작물의 생산량이 주목적이지만, 잔디밭 관리의 목적은 생산량이 아니기 때문에 근본적으로 칼륨요구 수준이 다르다. 최대의 엽조직 생산을 위해 요구되는 수준이상의 칼륨은 스트레스에 대한 내성을 증가시킬 수 있기 때문에 칼륨 시비 수준을 높일 경우 잔디밭에 유익하다. 또한 토양분석 실험에 대한 철학에도 차이가 있다. 어떤 연구소는 기본적인 양이온 치환의 용량 접근법(BCSR)을 선호하는 반면, 다른 연구소는 사용 가능한 성분의 충분양(SLAN)에 대한 컨셉을 사용한다. 연구소에 따라 이 두 가지 방법을 모두 사용할 수도 있다. BCSR 이론의 사용은 대부분 비료 살포 남용을 야기한다. 그리고 문제가 될만한 비료의 살포와 제품들은 때때로 양이온의 비율의 불균형을 예증하기 위해 사용된다. 토양 실험에 있어서의 BCSR 비율 이론의 유용성은 토양의 구성에 따라 달라질 수 있고 특히 모래로 조성된 지반에서 수행된 토양분석은 문제가 될 수 있다. 또 다른 토양 실험의 문제는 경기장 또는 골프장 그린에 사용된 모래지반이 유리된 칼슘 탄산염을 함유하고 있을 때 발생한다. pH7.0의 암모늄 초산염 추출액은 양이온 치환량의 측정과 양이온 비율의 측정을 한쪽으로 치우치게 할 수 있는 과다한 양의 칼슘을 용해한다. 용질의 pH를 8.1로 맞추는 것은 석회질 토양에서의 실험 절차의 정확성을 향상시킬 수 있다. Soil testing laboratories unfamiliar with turfgrasses will often overestimate the plant's need for phosphorus and underestimate the need for potassium. This is partly due to differences in rooting between grasses and many garden plants and crops. The grasses are generally more efficient in extracting phosphorus from the soil, reducing their need for phosphorus fertilizer. The fact that crop yield is often the primary objective in field crop production, and is usually of little interest in turfgrass management, may affect soil test interpretation for potassium. Potassium levels above those required for maximum tissue yield of grasses may improve stress tolerance and turfgrasses will usually benefit from higher applications of this element. There are also diffrrences in soil testing philosophies. Some laboratories use the sufficiency level of available nutrients(SLAN) approach, whereas others prefer the basic cation saturation ratio(BCSR) approach. Some will use a combination of the two methods. The use of the BCSR theory easily lends itself to abuse and questionable fertilizer applications and products are sometimes recommended citing imbalances in cation ratios. The usefulness of the BCSR ratio theory of soil testing varies with soil texture and interpretations on tests performed on sand-based media are particularly a problem. Other soil testing problems occur when sand-based media used on sports fields and golf greens contain free calcium carbonate. The ammonium acetate extractant at pH 7.0 dissolves excessive amounts of calcium that can bias cation exchange capacity measurements and measurements of cation ratios. Adjusting the pH of the extractant to 8.1 can improve the accuracy of the testing procedure for calcareous media.

Evaluationof Phosphorus Rateand Mixing Depthonthe Growthand Establishment of Kentucky bluegrass(Poapratensis L.) in Sand-Based Systems

이상국,David D. Minner,Nick E, Christians,Henry G. Taber 한국잔디학회 2009 Weed & Turfgrass Science Vol.23 No.2

Phosphorus (P) is one of the essential elements of the phospholipids that are involved in the formation of plant cell membranes. Phosphorus is highly immobile in soils and is often a limiting nutrient for plant growth. Phosphorus mobility and availability varies with several factors such as application frequency, placement in the soil, and the amount of irrigation or precipitation. This study was conducted to evaluate the effect of P applications at level of 0, 146, and 293 kg․ha-1 at four mixing depths (0, 7.6, 15.2, and 22.9 cm )on the growth and establishment of Kentucky bluegrass (Poapratensis L.) in a sand-based system.Grass clipping samples were collectedevery two weeks, dried, and weighed. Total root dry weight, root organic matter, and tissue content of P were measured at the end of the study. Leachate was collected weekly and analyzed for total P concentration. No difference was found between application of P to the surface and to the 7.6 cm mixing depth. However, surface application with 146 and 293 kg P․ha-1 produced 8-10% and 16-20% more P in tissue than subsurface applications, respectively Phosphorus (P) is one of the essential elements of the phospholipids that are involved in the formation of plant cell membranes. Phosphorus is highly immobile in soils and is often a limiting nutrient for plant growth. Phosphorus mobility and availability varies with several factors such as application frequency, placement in the soil, and the amount of irrigation or precipitation. This study was conducted to evaluate the effect of P applications at level of 0, 146, and 293 kg․ha-1 at four mixing depths (0, 7.6, 15.2, and 22.9 cm )on the growth and establishment of Kentucky bluegrass (Poapratensis L.) in a sand-based system.Grass clipping samples were collectedevery two weeks, dried, and weighed. Total root dry weight, root organic matter, and tissue content of P were measured at the end of the study. Leachate was collected weekly and analyzed for total P concentration. No difference was found between application of P to the surface and to the 7.6 cm mixing depth. However, surface application with 146 and 293 kg P․ha-1 produced 8-10% and 16-20% more P in tissue than subsurface applications, respectively

옥수수 ( Zea mays L. )와 소나무 ( Pinus densiflora L. ) 추출물의 생물학적 활성 ( Biological Activity of Extracts from Zea mays L. and Pinus densiflora L. )

주영규,Soul Chun,Nick E. Christians 한국잡초학회·한국잔디학회 1998 Weed & Turfgrass Science Vol.12 No.4

Evaluation of Various Slow-release Nitrogen Sources for Growth and Establishment of Poa pratensis L. on Sand-based Systems

이상국,David D. Minner,Nick E. Christians 한국잔디학회 2010 Weed & Turfgrass Science Vol.24 No.2

Nitrogen (N) is one of the most important nutrients among 17 essential nutrients for maintaining turfgrass color and quality. The slow release fertilizers were initially developed to provide a more consistent release of nitrogen over a longer period and are often used to decrease leaching potential from sandy soils. The goal of this study is to determine if various slow release N sources affect the rate at which turfgrass establishes. Six nitrogen sources were evaluated; Nitroform (38-0-0), Nutralene (40-0-0), Organiform (30-0-0), Sulfur coated urea (SCU, 37-0-0), urea (46-0-0), and Milorganite (6-0-0). The root zone media was seeded and sodded with ‘Limousine’ Kentucky bluegrass (Poa pratensis L.). Sodded pots produced 182 to 518 g more clipping dry weight than seeded pots. Among seeded pots,Milorganite produced greater amount of root dry weight than any other N sources. Because the period of turfgrass growth is different between sodded and seeded plots, there were differences on clipping yield and root growth. Overall,high N rate had turf color greater than acceptable color of 6 among seeded pots throughout the study. However, low N rate didn’t produce acceptable turf color throughout the study. Based on the result of this study, Milorganite would be recommended for new establishment of Kentucky bluegrass than urea with less clipping yield which can lead to reduce labor.