Precision and accuracy of visual foliar injury assessments

Journal Article · Thu Jul 01 00:00:00 EDT 1982 · J. Environ. Qual.; (United States)

DOI:https://doi.org/10.2134/jeq1982.00472425001100030043x· OSTI ID:5680976

Gumpertz, M L ^[1]; Tingey, D T; Hogsett, W E

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1. Northrop Services Inc., Corvallis, OR

The study compared three measures of foliar injury: (i) mean percent leaf area injured of all leaves on the plant, (ii) mean percent leaf area injured of the three most injured leaves, and (iii) the proportion of injured leaves to total number of leaves. For the first measure, the variation caused by reader biases and day-to-day variations were compared with the innate plant-to-plant variation. Bean (Phaseolus vulgaris 'Pinto'), pea (Pisum sativum 'Little Marvel'), radish (Rhaphanus sativus 'Cherry Belle'), and spinach (Spinacia oleracea 'Northland') plants were exposed to either 3 ..mu..L L/sup -1/ SO/sub 2/ or 0.3 ..mu..L L/sup -1/ ozone for 2 h. Three leaf readers visually assessed the percent injury on every leaf of each plant while a fourth reader used a transparent grid to make an unbiased assessment for each plant. The mean leaf area injured of the three most injured leaves was highly correlated with all leaves on the plant only if the three most injured leaves were <100% injured. The proportion of leaves injured was not highly correlated with percent leaf area injured of all leaves on the plant for any species in this study. The largest source of variation in visual assessments was plant-to-plant variation, which ranged from 44 to 97% of the total variance, followed by variation among readers (0-32% of the variance). Except for radish exposed to ozone, the day-to-day variation accounted for <18% of the total. Reader bias in assessment of ozone injury was significant but could be adjusted for each reader by a simple linear regression (R/sup 2/ = 0.89-0.91) of the visual assessments against the grid assessments.

• OSTI ID: 5680976
• Journal Information: J. Environ. Qual.; (United States), Vol. 11:3
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
54 ENVIRONMENTAL SCIENCES
LEAVES
INJURIES
OZONE
BIOLOGICAL EFFECTS
ACCURACY
AIR POLLUTION
EVALUATION
PLANTS
RELIABILITY
VARIATIONS
POLLUTION
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