Academic Journal
Using a One-Dimensional Convolutional Neural Network on Visible and Near-Infrared Spectroscopy to Improve Soil Phosphorus Prediction in Madagascar.
| Title: | Using a One-Dimensional Convolutional Neural Network on Visible and Near-Infrared Spectroscopy to Improve Soil Phosphorus Prediction in Madagascar. |
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| Authors: | Kawamura, Kensuke, Nishigaki, Tomohiro, Andriamananjara, Andry, Rakotonindrina, Hobimiarantsoa, Tsujimoto, Yasuhiro, Moritsuka, Naoki, Rabenarivo, Michel, Razafimbelo, Tantely, Cointault, Frédéric |
| Source: | Remote Sensing; Apr2021, Vol. 13 Issue 8, p1519, 1p |
| Abstract: | As a proximal soil sensing technique, laboratory visible and near-infrared (Vis-NIR) spectroscopy is a promising tool for the quantitative estimation of soil properties. However, there remain challenges for predicting soil phosphorus (P) content and availability, which requires a reliable model applicable for different land-use systems to upscale. Recently, a one-dimensional convolutional neural network (1D-CNN) corresponding to the spectral information of soil was developed to considerably improve the accuracy of soil property predictions. The present study investigated the predictive ability of a 1D-CNN model to estimate soil available P (oxalate-extractable P; Pox) content in soils by comparing it with partial least squares (PLS) and random forest (RF) regressions using soil samples (n = 318) collected from natural (forest and non-forest) and cultivated (upland and flooded rice fields) systems in Madagascar. Overall, the 1D-CNN model showed the best predictive accuracy (R2 = 0.878) with a highly accurate prediction ability (ratio of performance to the interquartile range = 2.492). Compared to the PLS model, the RF and 1D-CNN models indicated 4.37% and 23.77% relative improvement in root mean squared error values, respectively. Based on a sensitivity analysis, the important wavebands for predicting soil Pox were associated with iron (Fe) oxide, organic matter (OM), and water absorption, which were previously known wavelength regions for estimating P in soil. These results suggest that 1D-CNN corresponding spectral signatures can be expected to significantly improve the predictive ability for estimating soil available P (Pox) from Vis-NIR spectral data. Rapid and accurate estimation of available P content in soils using our results can be expected to contribute to effective fertilizer management in agriculture and the sustainable management of ecosystems. However, the 1D-CNN model will require a large dataset to extend its applicability to other regions of Madagascar. Thus, further updates should be tested in future studies using larger datasets from a wide range of ecosystems in the tropics. [ABSTRACT FROM AUTHOR] |
| Subject Terms: | CONVOLUTIONAL neural networks, OPTICAL spectroscopy, NEAR infrared spectroscopy, PHOSPHORUS in soils, STANDARD deviations |
| Geographic Terms: | MADAGASCAR |
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| ISSN: | 20724292 |
| DOI: | 10.3390/rs13081519 |
| Database: | Complementary Index |
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