Indirect measurement of leaf area index on the basis of path length distribution

2014 ◽  
Vol 155 ◽  
pp. 239-247 ◽  
Author(s):  
Ronghai Hu ◽  
Guangjian Yan ◽  
Xihan Mu ◽  
Jinghui Luo
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Path Length ◽  
Length Distribution ◽  
Indirect Measurement ◽  
Area Index

scholarly journals Determining a robust indirect measurement of leaf area index in California vineyards for validating remote sensing-based retrievals

2018 ◽  
Vol 37 (3) ◽  
pp. 269-280 ◽  
Author(s):  
William A. White ◽  
Maria Mar Alsina ◽  
Héctor Nieto ◽  
Lynn G. McKee ◽  
Feng Gao ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Indirect Measurement ◽  
Area Index

Scale Effect in Indirect Measurement of Leaf Area Index

2016 ◽  
Vol 54 (6) ◽  
pp. 3475-3484 ◽  
Author(s):  
Guangjian Yan ◽  
Ronghai Hu ◽  
Yiting Wang ◽  
Huazhong Ren ◽  
Wanjuan Song ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Scale Effect ◽  
Indirect Measurement ◽  
Area Index

scholarly journals Indirect Measurement of Leaf Area Index in Sagebrush-Steppe Rangelands

2012 ◽  
Vol 65 (2) ◽  
pp. 208-212 ◽  
Author(s):  
Julie A. Finzel ◽  
Mark S. Seyfried ◽  
Mark A. Weltz ◽  
James R. Kiniry ◽  
Mari-Vaughn V. Johnson ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Indirect Measurement ◽  
Sagebrush Steppe ◽  
Area Index

scholarly journals Indirect Measurement of Leaf Area Index in California North Coast Vineyards

HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 236-238 ◽  
Author(s):  
Lee F. Johnson ◽  
Lars L. Pierce
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Direct Measurement ◽  
Indirect Measurement ◽  
Field Of View ◽  
Planting Density ◽  
North Coast ◽  
Area Index ◽  
Measurement Protocol ◽  
Coast Region

The performance of the LI-COR LAI-2000 Plant Canopy Analyzer (PCA) for indirect measurement of leaf area index (LAI) was evaluated in vineyards of California's North Coast region. Twelve plots were established, representing vineyards of differing trellis, cultivar, and planting density. Mean LAI ranged from 0.5- to 2.25-m2 leaf area per m2 ground area by direct measurement (defoliation). Indirect LAI derived by a standard two-azimuth, diagonal-transect measurement protocol was significantly related to direct LAI (r2 = 0.78, P ≤ 0.001). However, the PCA underestimated direct LAI by about a factor of two. Narrowing the instrument's conical field of view from 148° to 56° increased indirect LAI by 13% to 60% in vertically trained plots, but still resulted in substantial underestimation of direct values. Use of this PCA protocol in vineyards should therefore be accompanied by direct measurement for calibration purposes.

scholarly journals An Empirical Protocol for Indirect Measurement of Leaf Area Index in Grape (Vitis vinifera L.)

HortScience ◽  
1993 ◽  
Vol 28 (8) ◽  
pp. 777-779 ◽  
Author(s):  
David A. Grantz ◽  
Larry E. Williams
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Canopy Structure ◽  
Indirect Measurement ◽  
Vitis Vinifera L ◽  
Indirect Methods ◽  
Area Index ◽  
Wide Row Spacing ◽  
Radiation Sensors

Leaf area development and canopy structure are important characteristics affecting yield and fruit quality of grapevines. Trellising systems and wide row spacing are common viticultural practices that violate key assumptions of currently available indirect methods of leaf area determination. We have developed a protocol for using a commercially available instrument to determine leaf area index (LAI) indirectly in a trellised vineyard. From knowledge of plant spacing, leaf area per vine can be calculated as required. A derived calibration equation resulted in a near 1:1 relationship (y = 0.00 + 1.00 X; r2 = 0.998) between actual and indirectly determined LAI over a range of LAI induced by irrigation treatments. The protocol involved covering 75% of the sensor with a manufacturer-supplied field of view delimiter and masking data from the outer three (of five) concentric radiation sensors. The protocol could form the basis for a general measurement technique, but may require local calibration.

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