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United States Department of Agriculture

Agricultural Research Service

Title: Cellulose Absorption Index (Cai) to Quantify Mixed Soil-Plant Litter Scenes

Authors
item Nagler, Pamela - ERLAB
item Inoue, Y - NIAES
item Daughtry, Craig
item Russ, Andrew

Submitted to: Remote Sensing of Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 6, 2003
Publication Date: October 30, 2003
Citation: Nagler, P.L., Inoue, Y., Glenn, E.P., Russ, A.L., Daughtry, C.S.T. 2003. Cellulose absorption index (CAI) to quantify mixed soil-plant litter scenes, Remote Sensing of Environment.87:310-325.

Interpretive Summary: Measurement of plant litter cover is an important tool in evaluating the effectiveness of conservation tillage practices. Current methods for measuring plant litter cover are tedious and somewhat subjective. The objectives of this work were to (1) acquire spectral reflectance data for mixed scenes of plant litter and soil and (2) evaluate the effectiveness of the spectral variable, cellulose absorption index (CAI), for quantifying plant litter on the soil. CAI describes the average depth of the cellulose absorption feature at 2100 nm in reflectance spectra. Positive values of CAI indicate the presence of cellulose. Scenes of known amounts of plant litter covering three contrasting soils were prepared and their reflectance spectra (400-2500 nm) were measured with a high resolution spectroradiometer. Litter from four crops (corn, soybean, rice, and wheat) and two trees (coniferous and deciduous) were included. The mean CAI of the soils was -2.0 while the mean CAI of the plant litter was 5.2. As the amount of plant litter in the scene increased from 0% (bare soil) to 100% cover, CAI increased linearly for each plant litter. The CAIs of mixed scenes with more than 10% litter cover were significantly larger than the CAIs of the soils. The results of this study indicated that CAI may be used to quantify plant litter cover, even at low percent cover. Future work will examine calculating CAI from shortwave infrared video images to assess plant litter cover.

Technical Abstract: Measurement of plant litter cover is an important tool in evaluating the effectiveness of conservation tillage practices. Current methods for measuring plant litter cover are tedious and somewhat subjective. The objectives of this work were to (1) acquire spectral reflectance data for mixed scenes of plant litter and soil and (2) evaluate the effectiveness of the spectral variable, cellulose absorption index (CAI), for quantifying plant litter on the soil. CAI describes the average depth of the cellulose absorption feature at 2100 nm in reflectance spectra. Positive values of CAI indicate the presence of cellulose. Scenes of known amounts of plant litter covering three contrasting soils were prepared and their reflectance spectra (400-2500 nm) were measured with a high resolution spectroradiometer. Litter from four crops (corn, soybean, rice, and wheat) and two trees (coniferous and deciduous) were included. The mean CAI of the soils was -2.0 while the mean CAI of the plant litter was 5.2. As the amount of plant litter in the scene increased from 0% (bare soil) to 100% cover, CAI increased linearly for each plant litter. The CAIs of mixed scenes with more than 10% litter cover were significantly larger than the CAIs of the soils. The results of this study indicated that CAI may be used to quantify plant litter cover, even at low percent cover. Future work will examine calculating CAI from shortwave infrared video images to assess plant litter cover.

Last Modified: 10/30/2014
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