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山东省冬小麦产量驱动因素与水肥调控研究:基于机器学习模型

Yield drivers and water and fertilizer management strategies for winter wheat in Shandong Province: a machine learning-based study

  • 摘要: 精准水肥管理是实现冬小麦高产高效生产的重要途径,但复杂田间条件下水、肥、土、气等多因素之间的非线性交互作用及其关键调控节点仍缺乏系统认识。本研究系统收集了2001~2024年山东省冬小麦田间试验文献数据,经数据筛选、缺失值处理和异常值剔除后,最终获得433条有效处理观测记录,构建机器学习模型分析产量形成的关键驱动因素及水肥调控路径。采用随机森林(RF)模型识别影响冬小麦产量的主要驱动因子,并利用分类与回归树(CART)模型提取具有农艺解释意义的产量分异节点。结果表明:1)灌溉量、施氮量和土壤有效磷含量具有较高预测贡献,是解释山东省冬小麦产量差异的关键变量;2)土壤碱化环境是限制产量潜力发挥的重要因素,当土壤pH≥8.19时,样本平均产量明显降低;在土壤容重较高(≥1.31 g/cm3)的条件下,较高生长季降水量(≥182.75 mm)与较低产量水平相关,表明土壤化学性质和物理结构共同影响产量形成;3)CART模型识别的高产分异路径表明,在本研究样本范围内,产量超过10 000 kg/hm2的高产样本主要出现在施氮量较高(≥225.00 kg/hm2)且施磷量相对较低(<112.50 kg/hm2)的组合条件下。RF与CART相结合的方法能够有效识别冬小麦产量形成的关键驱动因素及非线性分异路径,为区域水肥管理优化和精准调控提供理论参考。需要指出的是,本文识别出的水肥阈值属于基于文献整合数据获得的经验性节点,其适用性仍需多年多点田间试验进一步验证。

     

    Abstract: Precision water and fertilizer management is an important approach for achieving high-yield and high-efficiency winter wheat production. However, the nonlinear interactions among water, fertilizer, soil, and climatic factors under complex field conditions, as well as their key regulatory thresholds, remain insufficiently understood. This study systematically compiled field experimental data on winter wheat from published literature in Shandong Province during 2001-2024. After data screening, missing value processing, and outlier removal, 433 valid treatment observations were obtained to construct machine learning models for identifying key yield drivers and water-fertilizer management pathways. A random forest (RF) model was used to identify the major drivers influencing winter wheat yield, while a classification and regression tree (CART) model was applied to extract agronomically interpretable yield differentiation thresholds. The results showed that: (1) irrigation amount, nitrogen application rate, and soil available phosphorus exhibited high predictive importance and were key variables explaining winter wheat yield variation in Shandong Province; (2) soil alkalinity was an important constraint on yield potential. When soil pH ≥ 8.19, the mean yield of samples decreased significantly. Under conditions of high soil bulk density (≥1.31 g/cm3), higher growing-season precipitation (≥182.75 mm) was associated with lower yield levels, indicating that soil chemical properties and physical structure jointly affected yield formation; (3) the high-yield differentiation pathways identified by the CART model showed that, within the dataset analyzed, high-yield samples exceeding 10,000 kg/hm2 mainly occurred under combinations of relatively high nitrogen application rates (≥225.00 kg/hm2) and relatively low phosphorus application rates (<112.50 kg/hm2). The integrated RF and CART approach effectively identified the key yield drivers and nonlinear differentiation pathways of winter wheat, providing theoretical support for optimizing regional water and fertilizer management and improving precision management strategies. It should be noted that the water and fertilizer thresholds identified in this study represent empirical breakpoints derived from an integrated literature-based dataset, and their applicability requires further validation through multi-year and multi-site field experiments.

     

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