黑河中游主要农作物灌溉制度优化

科学的灌溉制度是干旱半干旱地区农业生产的重要保障。黑河位于西北干旱区，是我国第二大内陆河，且当地中游农业灌溉和下游生态需水矛盾十分突出。利用DSSAT （Decision Support for Agro-technology Transfer）模型模拟了黑河中游地区玉米、小麦、油菜、马铃薯的生长情况，对比分析了四种作物生育期内需水量变化与当地降水条件、现行灌溉制度之间的差异。通过设置灌溉组合探究了四种作物最适宜的灌溉制度，并计算了优化灌溉制度下的节水潜力。结果表明：DSSAT模型通过参数校正与验证后，对四种作物生长过程模拟性能较好，产量标准化均方根误差（nRMSE）均低于15.0%，决定系数（R²）均达到0.65以上。缺水量模拟结果表明，四种作物生长季平均水分亏缺介于122.5-367.0 mm。通过调整灌溉制度，可使玉米、小麦、油菜、马铃薯的水分利用效率分别提高54.8%、25.0%、18.3%和51.3%，且产量变幅均低于5.0%，实现了高产节水的目的。在研究区实施最优灌溉制度，中游农业灌区每年可以节省8.1×10⁸ m³的水资源量，用于支持下游生态保护。

Optimization of crop irrigation scheduling in the middle reaches of the Heihe River Basin

Scientific irrigation scheduling is essential for agricultural production in arid and semi-arid regions. Located in the northwest arid region, the Heihe River is the second largest inland (terminal lake) river in China and faces increasing competition for water between the middle reach agricultural irrigation and lower reach ecosystem services. In this study, we use the Decision Support for Agro-technology Transfer (DSSAT) model to simulate the growth of four main crops:maize, wheat, rape seed and potato in the middle reaches of the Heihe River Basin. We first compared the temporal differences between the water demands of the four crops and the precipitation during the growing season as well as the differences between the crop water demands and the current irrigation scheduling. Subsequently, we explored multiple irrigation scheduling combinations during the growth period to optimize irrigation scheduling of the four crops. Finally, we calculated the water saving potential under the optimal irrigation scheduling. Results show after calibration and validation with in situ observations, the DSSAT model has better simulation performance for the four crops in the study region. The standardized root mean square error (nRMSE) of the crop yields is less than 15.0%, and the coefficient of determination (R²) is above 0.65. The annual average water deficit of the four crops ranged from 122.5 to 367.0 mm during the growth season. By adopting the optimal irrigation scheduling, the water use efficiency of maize, wheat, rape seed, and potato could be improved by 54.8%, 25.0%, 18.3% and 51.3%, respectively, and the variation of the simulated crop yield was all lower than 5.0%, achieving both high yield and water conservation. If the optimal irrigation scheduling is applied in the study area, potential water saving could reach to 8.1×10⁸ m³ annually in the middle reaches, which could be used to support downstream ecological protection.