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ORIGINAL RESEARCH article

Front. Plant Sci.

Sec. Sustainable and Intelligent Phytoprotection

Volume 16 - 2025 | doi: 10.3389/fpls.2025.1659047

This article is part of the Research TopicInnovative Approaches in Remote Sensing for Precise Crop Yield Estimation: Advancements, Applications, and Future DirectionsView all 7 articles

Research on the Estimation Method of Crop Net Primary Productivity Based on Improved CASA Model

Provisionally accepted
宛凝  李宛凝 李1Zhuo  WangZhuo Wang1Chunling  ChenChunling Chen1Ying  YinYing Yin1Yuanji  CaiYuanji Cai1Hao  HanHao Han1Minghuan  LiuMinghuan Liu2Ziyi  FengZiyi Feng1*
  • 1Shenyang Agricultural University, Shenyang, China
  • 2North China University of Water Resources and Electric Power, Zhengzhou, China

The final, formatted version of the article will be published soon.

Net Primary Productivity (NPP) is a vital indicator for evaluating the carbon source and sink capacities of ecosystems, significantly influencing assessments of agricultural productivity and carbon cycle studies. Accurately estimating NPP in the agricultural sector, however, remains challenging. This research addresses the challenge by refining the estimation of the Fraction of Photosynthetically Active Radiation (FPAR) within the CASA model, introducing a novel methodology that significantly improves the accuracy of NPP estimation and, when applied to remote sensing imagery covering a broad region, demonstrates strong potential for large-scale crop NPP monitoring. We employed high-resolution Sentinel-2 satellite imagery and the Recursive Feature Elimination algorithm to extract FPAR-related features from 15 vegetation indices. The FPAR was subsequently estimated using a Convolutional Neural Network, leading to a dramatic decrease in the Root Mean Square Error (RMSE) from 0.2040 to 0.0020. The prediction errors for the improved model ranged from 0.0001 to 0.0092, with a mean absolute error (MAE) below 0.01. These values reflect the distribution of absolute residuals and indicate a substantial enhancement in accuracy over traditional methods. This improved FPAR estimation method was subsequently integrated into the CASA model. Compared to field-measured NPP data, the optimized model reduced the Mean Absolute Percentage Error (MAPE) from 28.92% to 20.31%. The MAPE values across the test samples ranged between 15% and 25%, indicating a significant improvement in model reliability. The optimised CASA model performs well in estimating net primary productivity (NPP) of crops, providing strong support for agricultural decision-making and future research on large-scale productivity and carbon cycling.

Keywords: CASA model, crop monitoring, Net primary productivity(NPP), Fraction ofPhotosynthetically Active Radiation (FRAR), vegetation index

Received: 03 Jul 2025; Accepted: 09 Oct 2025.

Copyright: © 2025 李, Wang, Chen, Yin, Cai, Han, Liu and Feng. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Ziyi Feng, fengziyi@syau.edu.cn

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