健康视角下我国南亚热带水田粮食产能关键限制因子识别——以广州市从化区为例

在国际粮食供需环境剧变及国内耕地非农化压力下,保障国家粮食安全,保证健康状态下耕地的粮食产能是全社会的重中之重。但是现有的耕地质量认知仍偏重于“自然环境本底”与“投入-产出”作用的耦合效应,缺乏从健康视角对耕地粮食产能关键限制因子的多维度考量。以广州市从化区为研究区,在大量样本采样检测和实地调研测产的基础上,采用地理探测器识别了健康视角下我国南亚热带水田粮食产能关键限制因子。结果表明：我国南亚热带水田粮食产能受地理环境健康背景、土壤健康状况和农田健康人工环境3个健康维度协同影响,三者贡献力分别为2.702、2.025和1.200,13个影响因素贡献力（q值）介于0.012~0.865之间,36个影响因子贡献力介于0.004~0.537之间。健康视角下我国南亚热带水田粮食产能关键限制因子主要为农田水文条件、土壤物理与微量元素健康状况、土壤侵蚀状况、生产保障措施和人为管理强度中的7个因子,其贡献力介于0.299~0.537之间,贡献力大小依次为：表土质地 > 平均水位变化 > 农作活动频率 > 土壤侵蚀程度 > 灌溉保障能力 > 有效硅含量 > 灌溉方法。受现代农业种植策略影响,我国南亚热带水田中土壤肥力、酸碱度和生物健康水平普遍较高,但土壤有效硅含量严重不足,基于灌溉保障和灌溉方法的农田精准水环境管理措施也亟需重视。可见,农田粮食产能的“木桶效应”仍严重威胁粮食安全,导致粮食产能的不稳定性与空间差异性,建议高度重视不同土壤类型中的微量元素健康状况及农作物生长过程中水环境的精准管理。

Key limiting factors of grain productivity in subtropical southern Chinese paddy fields from a land-health perspective

Ensuring national food security and healthy land for grain production is a priority because of changes to international agricultural supply and demand and domestic non-agricultural commodities. Considerations for cultivated land quality still focus on coupling the "natural environmental background" and "input-output" and lack a multi-dimensional perspective. Paddy field grain productivity in subtropical southern China(Conghua District, Guangzhou City) was studied to identify the key limiting factors. Sampling, on-site investigations, and production measurements were completed with a Geodetector. The three primary health dimensions that influenced paddy field grain productivity were the geographical environment health background(q=2.702), the soil health status(q=2.025), and the farmland health artificial environment(q=1.200). In total, 36 influencing factors were observed, and the contributions(q values)ranged from 0.004 to 0.537. The key limiting factors were the farmland hydrological conditions, the soil physical and trace element health status, the soil erosion status, the production security measures, and the human management intensity. Their contributions ranged from 0.299 to 0.537 in the following order:soil texture > average water level change > farming activity frequency > soil erosion degree > irrigation support capacity > available silicon content > irrigation method. Using a modern agricultural planting strategy, the soil fertility, pH, and microbial activity health levels were high, but the available silicon content was insufficient. These results suggest that managing the farmland water environment(i. e., irrigation guarantee and irrigation methods) is important. The farmland grain production capacity "barrel effect" continues to threaten food security, leading to instability and spatial differences. Therefore, soil trace elements and water management during crop growth are critical factors for land health.