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Titolo:
AMBIENT OZONE AND ADVERSE CROP RESPONSE - AN EVALUATION OF NORTH-AMERICAN AND EUROPEAN DATA AS THEY RELATE TO EXPOSURE INDEXES AND CRITICALLEVELS
Autore:
LEGGE AH; GRUNHAGE L; NOSAL M; JAGER HJ; KRUPA SV;
Indirizzi:
BIOSPHER SOLUT,1601 11TH AVE NW CALGARY AB T2N 1H1 CANADA
Titolo Testata:
Journal of Applied Botany
fascicolo: 5-6, volume: 69, anno: 1995,
pagine: 192 - 205
SICI:
0949-5460(1995)69:5-6<192:AOAACR>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
TROPOSPHERIC OZONE; PROTECT VEGETATION; PLANT-RESPONSE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
72
Recensione:
Indirizzi per estratti:
Citazione:
A.H. Legge et al., "AMBIENT OZONE AND ADVERSE CROP RESPONSE - AN EVALUATION OF NORTH-AMERICAN AND EUROPEAN DATA AS THEY RELATE TO EXPOSURE INDEXES AND CRITICALLEVELS", Journal of Applied Botany, 69(5-6), 1995, pp. 192-205

Abstract

This paper provides an overview of present ambient critical levels, objectives, guidelines, etc., for ozone and a brief review of the current research efforts in the U.S. and in Europe (UN-ECE, Economic Commission for Europe) to relate O-3 exposure statistics to adverse crop yield responses. These studies are based on retrospective statistical analyses of data from the U.S. NCLAN (National Crop Loss Assessment Network) and the EOTCP (European Open-Top Chambers Programme). In these investigations, a sigmoidal O-3 concentration weighting function and/or different types of summation techniques have been used. For example, inthe U.S., from a regulatory perspective, one of the descriptors of O-3 exposure is SUM06 (sum of all hourly concentrations above 60 ppb). Based on this statistic, it was predicted that a three month growing season SUM06 value of 26.4 ppm . hours of O-3 would protect 50 % of the crops from yield losses of > 10 %. In contrast, in the UN-ECE studies,an exposure index or critical level of AOT40 (Accumulated exposure Over Threshold of 40 ppb) was selected as the best predictor of adverse crop response and has been used to predict yield losses in spring wheat, green beans and clover. Most recently we have also statistically analyzed both the NCLAN and the EOTCP data retrospectively. The results showed that the cumulative frequency of occurrence of intermediate or moderate hourly O-3 concentrations is important in crop yield loss response. While our NCLAN data analysis showed that the cumulative frequency of occurrence of hourly O-3 concentrations between 50 and 87 ppb is the best predictor of crop response in the U.S., the corresponding results from EOTCP showed a range of 35 to 60 ppb as being important inEurope. There is a debate at the present time as to whether peak or moderate O-3 concentrations are critical in causing 3 crop yield reductions. The resolution of this issue is related to O-3 concentrations that occur when both the atmosphere and the phytosphere are sufficientlyconductive for optimal O-3 flux (exposure potential) and uptake. In this context, summary results from a number of independent studies are reviewed to further underscore the significance of moderate O-3 concentrations. In addition, results on the relevance of moderate or intermediate O-3 concentrations are explained in this paper with the use of an independent hybrid, statistical-mechanistic (micro-meteorological) approach. Here the concept includes the importance of ambient O-3 concentrations as they relate to the atmospheric conductivity and the physiological and functional properties of the plant. Further, we provide the numerical equations for applying this approach in O-3 measurement networks, the results of which, can be coupled with crop specific biology by using descriptors such as the ''growing degree days. '' It is concluded that these types of efforts will be very valuable in significantly reducing the current controversy associated with the presently popular single point, statistical cause-effect models and the scaled uncertainties consequently associated with regional scale assessments of ambient O-3-induced crop loss through the application of such models.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 11/07/20 alle ore 04:46:17