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| DOI：10.13522/j.cnki.ggps.2025137 |
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| Spatiotemporal variation in net irrigation and its effects on water consumption and wheat-maize yield in southern and central Hebei Province |
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WANG Yan, WANG Xingwang, QU Yanping, CHANG Wenjuan
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1. College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang 443002, China;
2. China Institute of Water Resources and Hydropower Research, Beijing 100038, China
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| Abstract: |
| 【Objective】Annual wheat -maize rotation is a dominant cropping system in Hebei Province, in which both crops require irrigation during their growing periods. This paper proposes a method to estimate the spatiotemporal variation of their net irrigation and its effects on water use and yields of the two crops in the region.【Method】The analysis focused on the southern and central parts of the province. Twenty years of eight-day average net irrigation were estimated using a water balance approach that incorporated precipitation, soil moisture changes and evapotranspiration. The accuracy of the estimates was tested against statistical records and published results. Crop yields at the municipal scale were analyzed using the random forest method to assess the importance of different components of the water balance in influencing water use and yields of the two crops.【Result】① The estimated net irrigation agreed well with data from the Hebei Water Resources Bulletin, with R2=0.94. Other comparisons also revealed that the estimated results were within acceptable error ranges. ② Spatially, the net irrigation of summer maize was higher in the central plains and lower in the surrounding mountainous and coastal areas of the study region. Temporally, our results showed that the net irrigation decreased on average over the past 20 years, although it showed interannual fluctuations. Irrigation demand peaked in June, accounting for 49.92% of the total irrigation amount. On average, 27% of evapotranspiration came from irrigation water. ③ Spatially, the net irrigation of winter wheat was markedly higher in the central region, while temporally, it remained relatively unchanged over the past 20 years. Peak irrigation occurred in April and May, with the former and latter accounting for 23.25% and 39.93% of the total irrigation amount, respectively. On average, irrigation water contributed 30% of the total evapotranspiration. ④ Summer maize yield was mainly influenced by the irrigation-to-evapotranspiration ratio in Hengshui, Langfang, and Xingtai, while winter wheat yield was correlated with soil water content in Shijiazhuang, Baoding, and Langfang.【Conclusion】Our results show a clear spatiotemporal variation in net irrigation and this variation affects the evapotranspiration and wheat-maize yield. These findings can help optimize agricultural water management and improve crop yields in the study region. |
| Key words: net irrigation; summer maize; winter wheat; evapotranspiration; yield |
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