Stable water isotope analysis of plant-soil interspecific interactions in wheat-maize intercropping

作者：Duo-Peng Shi, Yingbo Liu, Yuxian Cui, An-Yu Zhao, He-Zhe Sun, Liang Xue, Wen‐Feng Cong, Muhammad Ali Raza, Liqin Zhang · 发表于：Agricultural Water Management · 年份：2025 · DOI：10.1016/j.agwat.2025.109747 · 被引用次数：5 · 研究领域：Agronomic Practices and Intercropping Systems、Agroforestry and silvopastoral systems、Soil Management and Crop Yield

Stable water isotope tracing is an effective tool for quantifying plant water sources; however, interspecific competition and root stratification mechanisms in intercropping systems remain insufficiently validated through isotopic methods. Thus, to address this gap, a field study in semi-arid northwest China (Baiyin, Gansu; 209 mm annual precipitation) was carried on wheat-maize intercropping system encompassing treatments of monoculture wheat, monoculture maize, and intercropping. Water distribution mechanisms were evaluated using hydrogen-oxygen isotopes (δ²H/δ¹⁸O) combined with the MixSIAR model. The results demonstrated that intercropping provided synergistic benefits through vertical root stratification, whereby wheat primarily accessed shallow soil water, while maize relied on deep water layers. Net area yields significantly increased under intercropping for both wheat (7877 kg ha −1 , +17 %) and maize (27,959 kg·ha −1 , +58 %) compared to monoculture. Net water use efficiency of intercropped maize increased by 45 %. Border row wheat exhibited a more balanced water uptake across soil layers (shallow: 33 %, middle: 36 %, deep: 31 %), enhancing biomass accumulation and yield components. Middle-row maize showed 75 % higher flowering-stage biomass than border rows, attributed to preferential water use from middle soil layer (28 %), which reduced interspecific competition. Post wheat harvest, deep soil water storage in the maize strip increased by 8 %. A 30 cm row spacing ef...