Multi-spectral Reflectance of Warm-Season Turfgrasses as Influenced by Deficit Irrigation

이준희,Laurie E. Trenholm,J. Bryan Unruh 한국잔디학회 2008 Weed & Turfgrass Science Vol.22 No.1

Remote sensing using multispectral radiometry may be a useful tool to detect drought stress in turf. The objective of this research was to investigate the correlation between drought stress and multispectral reflectance (MSR) from the turf canopy. St. Augustinegrass (Stenotaphrum secundatum[Walt.] Kuntze.) cultivars ‘Floratam’ and ‘Palmetto’, ‘SeaIsle 1’ seashore paspalum (Paspalum vaginatum Swartz.), ‘Empire’ zoysiagrass (Zoysia japonica Steud.), and ‘Pensacola’ bahiagrass (Paspalum notatumFlugge) were established in lysimeters in the University of Florida Envirotron greenhouse facility in Gainesville. Irrigation was applied at 100%, 80%, 60%, or 40% of evapotranspiration (ET). Weekly evaluations included: a) shoot quality, leaf rolling, leaf firing b) soil moisture, chlorophyll content index; c) photosynthesis and d) multispectral reflectance. All the measurements were correlated with MSR data. Drought stress affected the infrared spectral region more than the visible spectral region. Reflectance sensitivity to water content of leaves was higher in the infrared spectral region than in the visible spectral region. Grasses irrigated at 100% and 80% of ET had no differences in normalized difference vegetation indices (NDVI), leaf area index (LAI), and stress indices. Grasses irrigated at 60% and 40% of ET had differences in NDVI, LAI, and stress indices. All measured wavelengths except 710nm were highly correlated (P < 0.0001) with turf visual quality, leaf firing, leaf rolling, soil moisture, chlorophyll content index, and photosynthesis. MSR could detect drought stress from the turf canopy.

Physiological Responses of Warm-Season Turfgrasses under Deficit Irrigation

Lee, Joon-Hee,Trenholm, Laurie. E.,Unruh, J. Bryan Turfgrass Society of Korea 2009 한국잔디학회지 Vol.23 No.1

본 연구는 전 세계적으로 물 부족 현상으로 인한 물의 사용에 대한 관심이 증가함에 따라 네 종류의 난지형 잔디에 각기 다른 비율의 적자란수를 함으로써 식물의 생리학적인 반응, 즉 시각적 품질, 잎의 물 함량, 엽록소 함량, 광합성, 물 이용효율 등이 어떤 반응을 보이는지를 이해하고 그에 따른 상관관계를 분석 해보고자 했다. 결론적으로 20% 정도 적자 관수를 했을 때 식물은 약간의 스트레스를 받는 상태에서도 적자 관수를 하지 않은 식물과 비교했을 때 광합성량의 차이가 없었으며 가장 이상적인 생리학적인 반응을 보였다. 뿌리 발육 부분에 있어서도 적자관수를 통한 건조스트레스는 깊은 뿌리 생육을 촉진하는 관리방법으로 적용되었다. 다음 연구는 잔디가 각기 다른 토양 수분상태에서 일정하게 유지되었을때 지상부와 지하부의 생육에 따른 생리학적인 반응에 대한 연구로 확대되어야 할 것이다. Due to increasing concerns over issues with both water quantity and quality for turfgrass use, research was conducted to determine the response of five warm-season turfgrasses to deficit irrigation and to gain a better understanding of relative drought tolerance. St. Augustinegrass(Stenotaphrum secundatum [Walt.] Kuntze.) cultivars 'Floratam' and 'Palmetto', 'SeaIsle 1' seashore Paspalum(Paspalum vaginatumSwartz.), 'Empire' zoysiagrass(Zoysia japonica Steud.), and 'Pensacola' bahiagrass(Paspalum notatum Flugge) were established in lysimeters in the University of Florida Envirotron greenhouse facility in Gainesville. Irrigation was applied at100%, 80%, 60%, or 40% of evapotranspiration(ET). Evaluations included: a) shoot quality, leaf rolling, leaf firing; b) leaf relative water content(RWC), soil moisture content, chlorophyll content index(CCI), canopy photosynthesis(PS); c) multispectral reflectance(MSR); d) root distribution; and e) water use efficiency. Grasses irrigated at 100% and 80% of ET had no differences in visual quality, leaf rolling, leaf firing, RWC, CCI, and PS. Grasses irrigated at 60% of ET had higher values in physiological aspects than grasses irrigated at 40% of ET. 'Sealsle 1' and 'Palmetto' had a deeper root system than 'Empire' and 'Pensacola', while 'Floratam' had the least amount of root mass. Photosynthesis was positively correlated with visual assessments such as turf quality, leaf rolling, leaf firing, and sensor-based measurements such as CCI, soil moisture, and MSR. Reducing the amount of applied water by 20% did not reduce turfgrass quality and maintained acceptable physiological functioning.

Multi-Spectral Reflectance of Warm-Season Turfgrasses as Influenced by Deficit Irrigation

Lee, Joon-Hee,Trenholm, Laurie. E.,Unruh, J. Bryan Turfgrass Society of Korea 2008 한국잔디학회지 Vol.22 No.1

Multi-spectral radiometer (MSR)를 사용한 리모트 센싱 기술이 향 후 잔디의 건조스트레스를 감지할 수 있는 도구로 사용될 수 있다. 본 연구의 목적은 네가지 각기 다른 조건의 건조스트레스를 받은 난지형 잔디의 잎에서 반사되는 Reflectance와 토양수분, 비주얼 잔디상태, 엽록소 함량, 광합성 등을 측정하여 각 factor간의 상관관계를 조사했으며 본 연구를 통해 모든 factor가 MSR 데이터와 질은 상관관계를 가지고 있었다. 또한 Reflectance 민감도는Visual spectral region보다 Infrared spectral region에서 더 높음을 알 수 있었다. 모든 결과를 종합해 볼 때 Multi-spectral radiometer (MSR)은 잔디의 건조상태를 미리 예측할 수 있는 도구로 사용될 수 있음을 확인할 수 있었다. 이 기술의 자료를 활용하게 된다면 향 후 MSR이 부착된 기구(Balloon)를 이용한 필드 스터디 연구로 확대될 수 있을 것이다. Remote sensing using multispectral radiometry may be a useful tool to detect drought stress in turf. The objective of this research was to investigate the correlation between drought stress and multispectral reflectance (MSR) from the turf canopy. St. Augustinegrass (Stenotaphrum secundatum[Walt.] Kuntze.) cultivars 'Floratam' and 'Palmetto', 'SeaIsle 1' seashore paspalum Paspalum vaginatum Swartz.), 'Empire' zoysiagrass (Zoysia japonica Steud.), and 'Pensacola' bahiagrass (Paspalum notatumFlugge) were established in lysimeters in the University of Florida Envirotron greenhouse facility in Gainesville. Irrigation was applied at 100%, 80%, 60%, or 40% of evapotranspiration (ET). Weekly evaluations included: a) shoot quality, leaf rolling, leaf firing b) soil moisture, chlorophyll content index; c) photosynthesis and d) multispectral reflectance. All the measurements were correlated with MSR data. Drought stress affected the infrared spectral region more than the visible spectral region. Reflectance sensitivity to water content of leaves was higher in the infrared spectral region than in the visible spectral region. Grasses irrigated at 100% and 80% of ET had no differences in normalized difference vegetation indices (NDVI), leaf area index (LAI), and stress indices. Grasses irrigated at 60% and 40% of ET had differences in NDVI, LAI, and stress indices. All measured wavelengths except 710nm were highly correlated (P < 0.0001) with turf visual quality, leaf firing, leaf rolling, soil moisture, chlorophyll content index, and photosynthesis. MSR could detect drought stress from the turf canopy.

Sensor-based Technology for Assessing Drought Stress in Two Warm-Season Turfgrasses

이준희,허재호,Lee, Joon-Hee,Trenholm, Laurie E.,Unruh, J. Bryan,Hur, Jae-Ho Turfgrass Society of Korea 2006 한국잔디학회지 Vol.20 No.2

본 연구는 토양 수분함량을 즉시 파악할 수 있는 Time Domain Radiometer(TDR)과 식물의 광합성 시 잎에서 반사되는 Reflectance를 통하여 식물의 상태를 파악할 수 있는 Multi-spectral radiometer(MSR)를 사용하여 난지형 잔디인 'Sea Isle 1' Seashore paspalum 과 'Floratam' St. Augustinegrass를 대상으로 토양수분함량과 Reflectance와의 상관관계를 파악하고자 시작하였다. 본 연구를 통해 토양 수분함량이 660, 694 wavelengths와 NDVI, LAI, stress index에서 높은 상관관계를 가지고 있음을 알 수 있었다. 이는 Sensor-based technology가 잔디의 수분요구 시점을 미리 파악할 수 있는 기술의 기초 자료로서 활용될 수 있으며 여러 다른 Sensor-based technology를 이용한 연구로 확대될 수 있을 것이다. This study was designed to determine what sensor-based technologies might reliably and accurately predict irrigation scheduling needs of warm-season turfgrass. 'Floratam' St. Augustinegrass[Stenotaphrum secundatum(Walt.) Kuntze] and 'Sea Isle I' seashore paspalum(Paspalum vaginatum Swartz) were established in tubs in the Envirotron Turfgrass Research Laboratory in Gainesville, FL in the spring of 2002. Each grass was subjected to repeated dry-down cycles where irrigation was withheld. Sensor-based data were collected and these evaluations were used to determine if irrigation scheduling could be determined based on plant response during dry-down. Results indicated that reflectance indices($P{\le}0.001$) and soil moisture($P{\le}0.0001$) throughout the dry-down cycle can predict the need for irrigation scheduling as turf quality declined below acceptable levels.

Physiological Responses of Warm-Season Turfgrasses under Deficit Irrigation

Joon-Hee Lee,Laurie. E. Trenholm,J. Bryan Unruh 한국잔디학회 2009 Weed & Turfgrass Science Vol.23 No.1

Due to increasing concerns over issues with both water quantity and quality for turfgrass use, research was conducted to determine the response of five warm-season turfgrasses to deficit irrigation and to gain a better understanding of relative drought tolerance. St. Augustinegrass(Stenotaphrum secundatum [Walt.] Kuntze.) cultivars ‘Floratam’ and ‘Palmetto’, ‘SeaIsle 1’ seashore paspalum(Paspalum vaginatumSwartz.), ‘Empire’ zoysiagrass(Zoysia japonica Steud.), and ‘Pensacola’ bahiagrass(Paspalum notatum Flugge) were established in lysimeters in the University of Florida Envirotron greenhouse facility in Gainesville. Irrigation was applied at100%, 80%, 60%, or 40% of evapotranspiration(ET). Evaluations included: a) shoot quality, leaf rolling, leaf firing; b) leaf relative water content(RWC), soil moisture content, chlorophyll content index(CCI), canopy photosynthesis(PS); c) multispectral reflectance(MSR); d) root distribution; and e) water use efficiency. Grasses irrigated at 100% and 80% of ET had no differences in visual quality, leaf rolling, leaf firing, RWC, CCI, and PS. Grasses irrigated at 60% of ET had higher values in physiological aspects than grasses irrigated at 40% of ET. ‘SeaIsle 1’ and ‘Palmetto’ had a deeper root system than ‘Empire’ and ‘Pensacola’, while ‘Floratam’ had the least amount of root mass. Photosynthesis was positively correlated with visual assessments such as turf quality, leaf rolling, leaf firing, and sensor-based measurements such as CCI, soil moisture, and MSR. Reducing the amount of applied water by 20% did not reduce turfgrass quality and maintained acceptable physiological functioning. Due to increasing concerns over issues with both water quantity and quality for turfgrass use, research was conducted to determine the response of five warm-season turfgrasses to deficit irrigation and to gain a better understanding of relative drought tolerance. St. Augustinegrass(Stenotaphrum secundatum [Walt.] Kuntze.) cultivars ‘Floratam’ and ‘Palmetto’, ‘SeaIsle 1’ seashore paspalum(Paspalum vaginatumSwartz.), ‘Empire’ zoysiagrass(Zoysia japonica Steud.), and ‘Pensacola’ bahiagrass(Paspalum notatum Flugge) were established in lysimeters in the University of Florida Envirotron greenhouse facility in Gainesville. Irrigation was applied at100%, 80%, 60%, or 40% of evapotranspiration(ET). Evaluations included: a) shoot quality, leaf rolling, leaf firing; b) leaf relative water content(RWC), soil moisture content, chlorophyll content index(CCI), canopy photosynthesis(PS); c) multispectral reflectance(MSR); d) root distribution; and e) water use efficiency. Grasses irrigated at 100% and 80% of ET had no differences in visual quality, leaf rolling, leaf firing, RWC, CCI, and PS. Grasses irrigated at 60% of ET had higher values in physiological aspects than grasses irrigated at 40% of ET. ‘SeaIsle 1’ and ‘Palmetto’ had a deeper root system than ‘Empire’ and ‘Pensacola’, while ‘Floratam’ had the least amount of root mass. Photosynthesis was positively correlated with visual assessments such as turf quality, leaf rolling, leaf firing, and sensor-based measurements such as CCI, soil moisture, and MSR. Reducing the amount of applied water by 20% did not reduce turfgrass quality and maintained acceptable physiological functioning.

Sensor-based Technology for Assessing Drought Stress in Two Warm-Season Turfgrasses

Jae-Ho Hur(허재호),J. Bryan Unruh,Laurie E. Trenholm,Joon-Hee Lee(이준희) 한국잡초학회·한국잔디학회 2006 Weed & Turfgrass Science Vol.20 No.2

본 연구는 토양 수분함량을 즉시 파악할 수 있는 Time Domain Radiometer(TDR) 과 식물의 광합성 시 잎에서 반사되는 Reflectance를 통하여 식물의 상태를 파악할 수 있는 Multi-spectral radiometer(MSR)를 사용하여 난지형 잔디인 ‘Sea Isle 1' Seashore paspalum 과 ‘Floratam' St. Augustinegrass를 대상으로 토양수분함량과 Reflectance와의 상관관계를 파악하고자 시작하였다. 본 연구를 통해 토양 수분함량이 660, 694 wavelengths와 NDVI, LAI, stress index에서 높은 상관관계를 가지고 있음을 알 수 있었다. 이는 Sensor-based technology가 잔디의 수분요구 시점을 미리 파악할 수 있는 기술의 기초 자료로서 활용될 수 있으며 여러 다른 Sensor-based technology를 이용한 연구로 확대될 수 있을 것이다. This study was designed to determine what sensor based technologies might reliably and accurately predict irrigation scheduling needs of warm season turfgrass. ‘Floratam’ St. Augustinegrass[Stenotaphrum secundatum(Walt.) Kuntze] and ‘Sea Isle I’ seashore paspalum(Paspalum vaginatum Swartz) were established in tubs in the Envirotron Turfgrass Research Laboratory in Gainesville, FL in the spring of 2002. Each grass was subjected to repeated dry down cycles where irrigation was withheld. Sensor based data were collected and these evaluations were used to determine if irrigation scheduling could be determined based on plant response during dry down. Results indicated that reflectance indices(P≤ 0.001) and soil moisture(P≤ 0.0001) throughout the dry down cycle can predict the need for irrigation scheduling as turf quality declined below acceptable levels.

Prediction of Micropollutant Elimination during Ozonation of Municipal Wastewater Effluents: Use of Kinetic and Water Specific Information

Lee, Yunho,Gerrity, Daniel,Lee, Minju,Bogeat, Angel Encinas,Salhi, Elisabeth,Gamage, Sujanie,Trenholm, Rebecca A.,Wert, Eric C.,Snyder, Shane A.,von Gunten, Urs American Chemical Society 2013 Environmental science & technology Vol.47 No.11

<P>Ozonation is effective in improving the quality of municipal wastewater effluents by eliminating organic micropollutants. Nevertheless, ozone process design is still limited by (i) the large number of structurally diverse micropollutants and (ii) the varying quality of wastewater matrices (especially dissolved organic matter). These issues were addressed by grouping 16 micropollutants according to their ozone and hydroxyl radical (<SUP>•</SUP>OH) rate constants and normalizing the applied ozone dose to the dissolved organic carbon concentration (i.e., g O<SUB>3</SUB>/g DOC). Consistent elimination of micropollutants was observed in 10 secondary municipal wastewater effluents spiked with 16 micropollutants (∼2 μg/L) in the absence of ozone demand exerted by nitrite. The elimination of ozone-refractory micropollutants was well predicted by measuring the <SUP>•</SUP>OH exposure by the decrease of the probe compound <I>p</I>-chlorobenzoic acid. The average molar <SUP>•</SUP>OH yields (moles of <SUP>•</SUP>OH produced per mole of ozone consumed) were 21 ± 3% for g O<SUB>3</SUB>/g DOC = 1.0, and the average rate constant for the reaction of <SUP>•</SUP>OH with effluent organic matter was (2.1 ± 0.6) × 10<SUP>4</SUP> (mg C/L)<SUP>−1</SUP> s<SUP>–1</SUP>. On the basis of these results, a DOC-normalized ozone dose, together with the rate constants for the reaction of the selected micropollutants with ozone and <SUP>•</SUP>OH, and the measurement of the <SUP>•</SUP>OH exposure are proposed as key parameters for the prediction of the elimination efficiency of micropollutants during ozonation of municipal wastewater effluents with varying water quality.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2013/esthag.2013.47.issue-11/es400781r/production/images/medium/es-2013-00781r_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es400781r'>ACS Electronic Supporting Info</A></P>