Estimation of Leaf Area from Leaf and Total Mass Measurements in Peanut
- L. Ma ,
- F. P. Gardner and
- A. Selamat
Leaf area index (LAI) is important for light interception, radiation-use efficiency (RUE), and plant growth; however, determination LAI requires substantial capital investment, often not available in developing countries. On the assumption that there is a sufficiently close relationship between leaf area (LA) and leaf dry weight (LDW) and possibly total biomass (TBM), it should be possible to estimate LA from these parameters. Therefore, eight peanut (Arachis hypogaea L.) cultivars varying widely in growth habit were harvested at 10-d intervals, starting from 30 days after planting (DAP) until harvest maturity in 1989 and used to determine LA from both LDW and aboveground TBM. The relationship between LA and LDW and LA and TBM were determined by two statistical models: linear and nonlinear. The general nonlinear model (LA = 0.0234 × LDW0.97) derived from LDW gave the best fit (R2 = 0.98) and standard error (SE = 0.71), compared with the TBM model (LA = 0.0205 × TBM0.85; R2 = 0.95; SE = 0.83). Both LA-LDW and LA-TBM models were validated using data from an experiment conducted in 1985, which showed a good agreement between the estimated and measured LA. The LA-LDW nonlinear model produced estimations close to 1:1 (R2 = 0.98). Although cultivars exhibited disparate morphology and growth habit, specific cultivar models differed only slightly from one another. Therefore, we concluded that the general nonlinear model (LA =0.0234 ✕ LDW0.97) can accurately estimate leaf area of peanut canopies across a wide range of cultivars and growth stages.
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