Estimating leaf area index and light extinction coefficient using Random Forest regression algorithm in a tropical moist deciduous forest, India

Abstract. The specular bistatic scattering mechanism of Okra's crop was analyzed using dual polarized ground based bistatic scatterometer system at X, C, and L bands in the specular direction with the azimuthal angle(&theta;=0&deg;). An outdoor Okra crop bed of area 10&times;10m2 was specially prepared for the estimation of leaf area index (LAI) at HH and VV polarizations over the angular range of incidence angle 20&deg; to 60&deg; at steps of 10&deg;. The regression analysis was done between bistatic specular scattering coefficients and crop biophysical parameter at X, C, and L bands for HH and VV polarization at different angle of incidence to determine the optimum parameters of bistatic scatterometer system. The linear regression analysis showed the high correlation at 40&deg; angle of incidence for all bands and polarizations for the Okra crop. The computed scattering coefficients and measured LAI of Okra crop for the seven growth stages at 40&deg; angle of incidence were interpolated into 61 data sets. The data sets were divided into input, validation and testing for the training and testing of the developed random forest regression (RF) model for the estimation of LAI for Okra crop. The estimated values of LAI of Okra crop, by the developed RF regression model, were found more closer to the observed values at X band for VV polarization with coefficient of determination (R2=0.928) and low root mean square error (RMSE=0.260m2/m2) in comparison to C and L bands.

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Prediction of plant transpiration from environmental parameters and relative leaf area index using the random forest regression algorithm

Journal of Cleaner Production ◽

10.1016/j.jclepro.2020.121136 ◽

2020 ◽

Vol 261 ◽

pp. 121136 ◽

Cited By ~ 2

Author(s):

Li Li ◽

Shiwang Chen ◽

Chengfei Yang ◽

Fanjia Meng ◽

Nick Sigrimis

Keyword(s):

Random Forest ◽

Leaf Area Index ◽

Leaf Area ◽

Environmental Parameters ◽

Random Forest Regression ◽

Area Index ◽

Plant Transpiration

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Improvements in Plant Morphology Facilitating Progressive Yield Increases of japonica Inbred Rice since the 1980s in East China

Agriculture ◽

10.3390/agriculture11090834 ◽

2021 ◽

Vol 11 (9) ◽

pp. 834

Author(s):

Tianyao Meng ◽

Jialin Ge ◽

Xubin Zhang ◽

Xi Chen ◽

Guisheng Zhou ◽

...

Keyword(s):

Grain Yield ◽

Leaf Area ◽

Extinction Coefficient ◽

Plant Morphology ◽

Light Extinction ◽

East China ◽

Specific Leaf Weight ◽

Area Index ◽

Light Extinction Coefficient ◽

Spikelets Per Panicle

Grain yield was greatly increased during the genetic improvement of japonica inbred rice since the 1980s in Jiangsu, east China; thus, an improved plant morphology should be expected, considering that plant morphology is a decisive factor determining grain yield. Twelve representative japonica inbred rice released from 1983 to 2013 were grown in the same fields in 2019 and 2020. Grain yield increased (p < 0.01) at 63.3 kg ha−1 year−1 across 2 years among rice cultivars released in different periods. The genetic improvement in grain yield was associated with increased spikelets per panicle. Single panicle weight, number of primary and secondary branches, and number of grains on primary and secondary branches were all increased with a year of release. Generally, the width of top three leaves positively correlated (while angle of top three leaves and light extinction coefficient negatively) correlated (p < 0.01) with year of release. Leaf area per tiller and leaf area index at heading and maturity, specific leaf weight, leaf photosynthetic rate, and SPAD values after heading were all increased linearly with year of release. Plant height exhibited a positive (p < 0.01) trend with year of release, as well as stem weight per tiller and K and Si concentrations of stem. Spikelets per panicle, width of top three leaves, plant height, and leaf area index, and specific leaf weight after heading positively correlated (while angle of top three leaves and light extinction coefficient negatively) correlated (p < 0.01) with grain yield and single panicle weight. Our results suggested that modern japonica inbred rice exhibited expanded sink size by spikelets per panicle, higher leaf area through leaf width, optimized leaf photosynthetic capacity, lower leaf angle and light extinction coefficient, and enhanced stem strength. These improved plant morphologies facilitated yield increases of japonica inbred rice since the 1980s in east China.

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