Abstract: To clarify the effects of water-nitrogen coupling on soil moisture changes, water consumption characteristics, and yield of Astragalus membranaceus in the semi-arid region of Longxi, and to explore irrigation and fertilization patterns of efficient and reasonable suitable for local A. membranaceus, a water-nitrogen coupling experiment using drip irrigation under plastic film was conducted in Weiyuan County, Gansu Province, from April to October 2024.A two-factor experimental design was adopted, with soil moisture content set at two irrigation levels: 55%–70% of field capacity (W1) and 70%–85% of field capacity (W2), and three nitrogen levels: low nitrogen (62 kg·hm^–2, N1), medium nitrogen (84 kg·hm^–2, N2), and high nitrogen (106 kg·hm^–2, N3).The results showed that the soil water storage capacity at depths of 0–100 cm decreased as the astragalus growth period progressed. Appropriate increases in nitrogen fertilizer application reduced soil water consumption. The total water consumption, stage-specific water consumption, water consumption intensity, and water consumption coefficient were highest during the fruiting period of A. membranaceus. Among these, the W2N1 treatment had the highest total water consumption, reaching 674.3 mm; the W2N2 treatment had the highest water consumption and water consumption intensity, which were significantly higher than other water-nitrogen treatments by 3.0%–16.8% and 3.4%–17.9%, respectively, and significantly higher than the CK treatment by 39.8% and 39.4%, respectively. The W1N2 treatment had the highest water use coefficient, significantly higher than other water-nitrogen treatments by 5.4% to 17.3%, and significantly higher than the CK treatment by 2.1%. Different water and nitrogen treatments had a significant effect on the root diameter, root length, underground dry weight, and yield of A. membranaceus, with the W2N2 treatment yielding the highest results. Compared to other treatments, the W2N2 treatment significantly increased root diameter by 9.8% to 48.3%, root length by 5.6% to 22.4%, underground dry weight by 14.2% to 51.3%, and yield by 7.1% to 25.9%. This indicates that appropriate irrigation and nitrogen application can improve A. membranaceus' water use characteristics, promote root system absorption of soil moisture, and enhance water use efficiency. The W2N2 treatment cultivation model significantly increases root diameter, root length, and A. membranaceus yield.

Key words: Astragalus membranaceus, water-nitrogen coupling, sub-surface drip irrigation, soil moisture, water consumption characteristics, yield

摘要： 为明确水氮耦合效应对陇西半干旱区黄芪Astragalus membranaceus土壤水分变化、耗水特性及产量的影响，探索适宜当地黄芪高效合理的灌溉施肥模式，于2024年4～10月，在甘肃省渭源县开展膜下滴灌黄芪水氮耦合试验。采用双因素试验设计，设置土壤含水量为田间持水量的55%～70% (W1)、70%～85% (W2)两个灌水水平，及低氮(62 kg·hm^–2，N1)、中氮(84 kg·hm^–2，N2)和高氮(106 kg·hm^–2，N3)三个氮素水平。结果表明，各处理0～100 cm土壤贮水量随黄芪生育期的推进呈降低趋势，适当增加氮肥用量可减少土壤贮水消耗量。黄芪结果期的总耗水量、阶段耗水量、耗水强度、耗水模系数最大，其中，W2N1处理总耗水量最大，为674.3 mm；W2N2处理耗水量、耗水强度最大，分别较其他水氮处理显著提高3.0%～16.8%、3.4%～17.9%，较CK显著提高39.8%、39.4%；W1N2处理耗水模系数最大，较其他水氮处理显著提高5.4%～17.3%，较CK显著提高2.1%。不同水氮处理对黄芪根粗、根长、地下部干质量及产量有显著影响，其中W2N2处理最高，较其他处理分别显著提高9.8%～48.3%、5.6%～22.4%、14.2%～51.3%、7.1%～25.9%。说明适宜的灌水和施氮可改善黄芪耗水特性，促进其根系吸收土壤水分，提高水分利用率，W2N2处理的栽培模式能显著增加黄芪根粗、根长，并显著提高黄芪产量。

关键词: 黄芪, 水氮耦合, 膜下滴灌, 土壤水分, 耗水特性, 产量