基于多源数据的玉米地上生物量动态监测方法

Dynamic Monitoring Method for Aboveground Biomass of Maize Based on Multi-source Data

  • 摘要: 玉米地上生物量是监测长势的关键指标,早期精准监测对农业生产管理意义重大。研究于河北固城农业气象国家野外科学观测研究站开展田间试验,基于2020—2024年玉米分期播种数据,2020—2021年数据构建模型,2022—2024年数据进行应用。使用多元线性回归方法、偏最小二乘回归方法和随机森林方法,结合植被指数与气象因子,研究三叶期、七叶期、拔节期、抽雄期和三叶-抽雄期的地上生物量动态监测方法。结果表明:720~1300 nm波段与地上生物量相关性最强(相关系数为0.50~0.86,达到0.05显著性水平)。基于植被指数与气象因子的模型拟合效果优于单一植被指数模型,其中随机森林方法在单一发育期的表现显著更优。随机森林方法构建的三叶期、七叶期、拔节期和抽雄期地上生物量模型,决定系数分别为0.59、0.85、0.85和0.81,且各发育期模型应用决定系数均超过0.40。综上,引入气象因子可提升随机森林方法对地上生物量的模拟精度,为监测作物长势提供有效方法。

     

    Abstract: The aboveground biomass of maize is regarded as a crucial indicator for monitoring maize growth. However, it’s challenging to meet the practical needs for dynamic remote sensing of aboveground biomass during early growth stages. Field experiments are conducted at National Field Scientific Observation and Research Station of Agricultural Meteorology at Gucheng, Hebei Province. Based on data from maize staged sowing experiments conducted from 2020 to 2024, observations from 2020 to 2021 are utilized for model construction, while data from 2022 to 2024 are employed for model application. 3 modeling approaches, including multiple linear regression, partial least squares regression, and random forest are used to develop models for aboveground biomass at different growth stages, and models are compared by adopting a strategy combining vegetation indices with meteorological factors. Results show that spectral bands most strongly correlated with aboveground biomass mainly concentrate in 720-1300 nm range, with correlation coefficients ranging from 0.50 to 0.86 (passing the test of 0.05 level). When vegetation indices are combined with meteorological factors, such as effective accumulated temperature and total radiation, the performance of 3 models significantly improves compared to using vegetation indices, respectively. In various stages of individual development, the random forest method demonstrates the best performance in biomass simulation. In the test set, the corresponding coefficient of determination values are 0.59, 0.85, 0.85, and 0.81, respectively. Moreover, determination coefficients of aboveground biomass model applications at all growth stages are above 0.40. The study indicates that integrating vegetation indices with meteorological factors can significantly enhance the accuracy of aboveground biomass estimation models at different growth stages. The excellent performance of the random forest method highlights its potential for accurately estimating biomass dynamics. This integrated approach effectively addresses the challenge of monitoring maize during its early growth stages and provides a more accurate method for estimating aboveground biomass. In summary, combining vegetation indices with meteorological factors for aboveground biomass modeling is an effective strategy to improve the accuracy of maize growth monitoring. Research findings provide technical support for precise crop growth monitoring and refined agricultural management.

     

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