中国农业科学 ›› 2025, Vol. 58 ›› Issue (18): 3632-3647.doi: 10.3864/j.issn.0578-1752.2025.18.005

• 耕作栽培·生理生化·农业信息技术 • 上一篇    下一篇

无人机多光谱参数与Shapley分析融合的青贮玉米生物量估算

韩林蒲(), 马纪龙, 齐勇杰, 高嘉琪, 谢铁娜, 贾彪()   

  1. 宁夏大学农学院,银川 750021
  • 收稿日期:2025-03-12 接受日期:2025-06-09 出版日期:2025-09-18 发布日期:2025-09-18
  • 通信作者:
    贾彪,E-mail:
  • 联系方式: 韩林蒲,E-mail:hanlinpu2023@163.com。
  • 基金资助:
    国家自然科学基金(32360432)

Multispectral Unmanned Aerial Vehicle Parameters Combined with Machine Learning to Predict Silage Maize Biomass

HAN LinPu(), MA JiLong, QI YongJie, GAO JiaQi, XIE TieNa, JIA Biao()   

  1. College of Agriculture, Ningxia University, Yinchuan 750021
  • Received:2025-03-12 Accepted:2025-06-09 Published:2025-09-18 Online:2025-09-18

摘要:

【目的】地上部生物量是衡量作物生长状况的重要指标。探究单一光谱参数模型与融合不同生长阶段模型在青贮玉米地上部生物量(above ground biomass,AGB)估测中的精度差异,旨在比较无人机多光谱特征参数及模型融合方法对青贮玉米AGB估测模型精度的影响,以提高宁夏青贮玉米生物量监测的准确性,为青贮玉米生物量的动态监测提供一种可行的技术方案。【方法】采用大疆无人机M300 RTK搭载M600 Pro型多光谱相机,获取6个不同氮素水平下青贮玉米各个生长阶段的多光谱影像数据,分析不同处理下光谱反射率和植被指数与青贮玉米地上部生物量变化关系。将青贮玉米全生育期数据集划分为营养生长阶段数据集和生殖生长阶段数据集,并对2个不同生长阶段数据集进行相关性分析,选择关联程度高的多光谱植被指数作为建模数据的输入量,利用随机森林(RF)、卷积神经网络(BP)等机器学习方法构建青贮玉米不同生长阶段的AGB估测模型,并使用灰狼优化算法进行模型优化。最后利用Shapley分析法,将优化的青贮玉米不同生长阶段AGB估算模型进行组合,得到具有多光谱变化特征的青贮玉米全生育期AGB估算模型。【结果】划分2个不同生长阶段可以提高青贮玉米生物量与多光谱植被指数的关联性,其中绿色叶绿素植被指数(green chlorophyll vegetation index,GCVI)提升最高,相关性绝对值达到了0.61和0.64;利用Shapley组合后的RF模型精度相对较高,R2为0.89、均方根误差(root mean square error,RMSE)为1.31 kg·m-2;灰狼算法优化后的RF模型经Shapley组合后精度最高,R2为0.92、RMSE为1.11 kg·m-2。【结论】在青贮玉米各生长阶段筛选最优光谱参数,并利用Shapley分析集成多阶段建模,能够有效提升青贮玉米AGB预测模型的精度。

关键词: 青贮玉米, 地上部生物量, 无人机, 多光谱, Shapley分析, 机器学习

Abstract:

【Objective】Aboveground biomass is an important indicator of crop growth, in order to explore the accuracy difference between single spectral parameter model and fusion of different growth stage models in silage maize above ground biomass (AGB) estimation, this study aimed to compare the effects of unmanned aerial vehicle (UAV) multispectral feature parameters and model fusion methods on silage maize AGB estimation modeling accuracy, so as to improve the accuracy of silage maize biomass monitoring in Ningxia, and to provide a feasible technological solution for silage maize biomass dynamic monitoring. 【Method】DJI UAV M300 RTK equipped with M600 Pro multispectral camera was used to acquire multispectral image data of silage maize at each growth stage under six different nitrogen levels, and the relationship between the spectral reflectance and vegetation index and the change of biomass of silage maize in the upper part of the ground under different treatments were analyzed. The data set of silage maize in the whole life cycle were classified into the nutrient growth stage data set and reproductive growth stage data set, and the correlation analysis of the two different growth stage data sets were carried out. The multispectral vegetation index with high degree of correlation was selected as the input of modeling data, and the AGB estimation model of silage maize at different growth stages were constructed by using machine learning methods, such as Random Forest (RF) and Convolutional Neural Network (BP). The model was optimized by using the Gray Wolf Optimization Algorithm, and finally optimizing the model by using the Shapley Analysis. The optimized AGB estimation model of different growth stages of silage maize was combined to obtain the AGB estimation model of silage maize with multi-spectral change characteristics for the whole reproductive period. 【Result】The division of two different growth stages could improve the correlation between silage maize biomass and multispectral vegetation index, in which the green chlorophyll vegetation index (GCVI) improved with the highest value, and the absolute values of the correlation reached 0.61 and 0.64; the accuracy of the RF model after the combination using Shapley analysis was relatively high, with R2 of 0.89 and root mean square error (RMSE) of 1.31 kg·m-2; The RF model optimized by Gray Wolf algorithm with the Shapley combination had the highest accuracy with R2 of 0.92 and RMSE of 1.11 kg·m-2. 【Conclusion】 In this study, screening the optimal spectral parameters at each growth stage of silage maize and integrating multi-stage modeling using Shapley analysis could effectively improve the accuracy of silage maize AGB prediction model.

Key words: silage maize, above ground biomass, UAV, multispectral, Shapley analysis, machine learning