Ru Xiaoya, He Tianzhi, Yan Guochao, He Yong, Zhu Zhujun, Yu Qiang, He Jianqiang
College of Horticulture Science, Zhejiang A&F University, Hangzhou, Zhejiang, China.
Key Laboratory for Agricultural Soil and Water Engineering in Arid Area of Ministry of Education, Northwest A&F University, Yangling, Shaanxi, China.
Front Plant Sci. 2025 May 12;16:1572647. doi: 10.3389/fpls.2025.1572647. eCollection 2025.
Water shortages greatly challenge high-quality apple production in dryland agricultural regions. Bridging the gap between water use and apple crop water requirements, as well as clarifying water suitability levels, are essential steps to improve water use efficiency. This study innovatively introduced phenological models to accurately predict apples' phenological stages, thus constructing a dynamic crop coefficient (K) curve. By skillfully integrating this curve with classic FAO 56 Penman-Monteith (P-M) ET model, the water requirements (WR) and water suitability (S) were evaluated during apple flowering-fruit setting, fruit expansion, and coloring-maturity stages. The results showed that the average durations of the apple phenological stages were 22 days for flowering-fruit setting, 102 days for fruit expansion, and 39 days for fruit coloring-maturity. Unexpectedly, counterintuitive results emerged regarding water requirements and suitability across the phenophases. Despite the fruit expansion stage having the highest average water requirement (319 mm), multi-year data indicated 'relatively suitable' (S=0.8) conditions for most counties. In contrast, although the average water requirement during flowering-fruit setting was 120 mm, the suitability level was classified as 'unsuitable' (S=0.3), indicating a water shortage, particularly in Xinjiang, the northwest Loess Plateau, and northern Bohai Bay areas. The coloring-maturation stage, with an average water requirement of 113 mm, was classified as 'very suitable' (S=1.5), reflecting highly favorable conditions. As this stage progressed, over-humidity conditions began in the Southwestern Cool Highlands and spread to the southwestern Loess Plateau. These findings revealed that the relationship between water requirements and suitability was not linear and emphasized the critical need for focused water management during the flowering-fruit setting stage to ensure sustainable apple production.
水资源短缺给干旱地区的优质苹果生产带来了巨大挑战。弥合用水与苹果作物需水量之间的差距，并明确水分适宜水平，是提高用水效率的关键步骤。本研究创新性地引入物候模型来准确预测苹果的物候期，从而构建动态作物系数（K）曲线。通过巧妙地将该曲线与经典的粮农组织56彭曼-蒙特斯（P-M）ET模型相结合，评估了苹果开花坐果期、果实膨大期和着色成熟期的需水量（WR）和水分适宜性（S）。结果表明，苹果物候期的平均持续时间为：开花坐果期22天，果实膨大期102天，果实着色成熟期39天。出乎意料的是，各物候期的需水量和适宜性出现了与直觉相反的结果。尽管果实膨大期的平均需水量最高（319毫米），但多年数据显示，大多数县处于“相对适宜”（S=0.8）的条件。相比之下，虽然开花坐果期的平均需水量为120毫米，但适宜性水平被归类为“不适宜”（S=0.3），表明存在缺水情况，特别是在新疆、黄土高原西北部和渤海湾北部地区。着色成熟期的平均需水量为113毫米，被归类为“非常适宜”（S=1.5），反映出条件非常有利。随着这一阶段的推进，西南冷凉高地开始出现湿度偏高的情况，并蔓延至黄土高原西南部。这些发现表明，需水量与适宜性之间的关系并非线性，并强调了在开花坐果期进行针对性水分管理以确保苹果可持续生产的迫切需求。
