Soil water deficit is one of the important factors affecting the source–sink balance of sweetpotato at mid-season growth (storage root initiation period). However, water regulation at mid-season sweetpotato growth is often ignored. In this study, field trials were conducted to diagnose leaves in the middle of sweetpotato growth, and then three mid-season irrigation levels (CK: 0 m³/hm²; W₁: 150 m³/hm²; W₂: 300 m³/hm²) were established. The effects of different irrigation levels on photosynthetic physiological indexes, ¹³C transfer allocation, and yield of sweetpotato were studied. The results revealed that mid-season irrigation significantly increased the relative moisture content of sweetpotato leaves, maximum photochemical efficiency (F_v/F_m), and net photosynthetic rate (P_n) (P < 0.05), which effectively alleviated the effects of soil water deficit. The P_n values with irrigation treatments W₁ and W₂ were significantly higher than those with control (CK) treatment in all three study periods. Among these, the W₂ treatment had the highest P_n at 70 d, a_n increase of 113.4% compared with CK in 2019 test, and W₁ had the highest P_n at 110 d and 150 d (P < 0.05). The trend of stomatal conductance (G_s) was basically consistent with P_n. The transpiration rate (T_r) of W₂ was the highest at 70 d, an increase of 59.8–69.7% compared with CK, but the T_r of W₁ was the highest at 110 d and 150 d. The ¹³C total accumulation in the W₁ treatment was the highest at 70 d, 110 d, and 150 d, when it was 21.9%, 20.4%, and 33.1% higher than that of the W₂ treatment in 2019 test (P < 0.05), respectively. The ¹³C allocation rate of storage roots treated with W₁ was the highest in all periods, reaching as high as 73.1–76.1% at 150 d (P < 0.05). At 70 d, the ¹³C allocation rate of fiber roots and stems was highest in the CK treatment, whereas the ¹³C allocation rate of leaves was highest in W₂ (P < 0.05). At 110 d and 150 d, the ¹³C allocation rate of stems and leaves in CK was the highest (P < 0.05). The biomass of W₂ was the highest at 70 d, but the root-to-shoot ratio and the dry weight of root became gradually lower than those of the CK and W₁ treatments at the late season, when they were reduced by 28.4% and 32.2% compared to W₁ at 150 d in 2019 test (P < 0.05). The yield of W₁ was increased significantly by 33.3–34.9% compared with CK (P < 0.05), but W₂ only had an increased production of 14.5–20.7% (P < 0.05) compared to CK (P < 0.05). The irrigation water utilization efficiency of W₂ was 59.4–61.8% and 39.1–43.5% lower than those of the CK and W₁ treatments (P < 0.05), respectively. Together, these results validate the field sweetpotato mid-season water management model, which is of great significance for guiding actual production of sweetpotato and increasing the potential of sweetpotato.

土壤水分亏缺是影响季节中期（贮藏根生期）甘薯源－库平衡的重要因素之一。然而，通常在季节中期，甘薯生长时的水分调节被忽略。在这项研究中，进行了田间试验以诊断甘薯生长中期的叶片，然后诊断三个中期灌溉水平（CK：0 m ³ / hm ²； W ₁：150 m ³ / hm ²； W ₂：300 m ³ / hm ²）被建立。不同灌溉水平对光合生理指标的影响，¹³研究了碳转移分配和甘薯的产量。结果表明，中季灌溉显着提高了甘薯叶片的相对含水量，最大光化学效率（F _v / F _m）和净光合速​​率（P _n）（P  <0.05），从而有效地减轻了土壤的影响。缺水。在所有三个研究阶段中，灌溉处理W ₁和W ₂的P _n值均显着高于对照处理（CK）的P _n值。其中，W ₂处理在70 d时具有最高的P _n，a _n与2019年试验的CK相比增加了113.4％，并且W ₁在110 d和150 d时具有最高的P _n（P  <0.05）。气孔导度（G _s）趋势与P _n基本一致。W ₂的蒸腾速率（T _r）在70 d时最高，与CK相比增加59.8〜69.7％，但W ₁的T _r在110 d和150 d时最高。在¹³中的W C总积累₁治疗是在70 d，110 d和150 d最高的，当它是21.9％，20.4％，和33.1％比W的更高2019年测试的_2种治疗 分别为（P <0.05）。W ₁处理的贮藏根的¹³ C分配率在所有时期最高，在150 d时高达73.1–76.1％（P  <0.05）。在70 d时，¹³纤维根C分布速率和茎是在CK治疗最高，而¹³叶的C分布率最高为W ₂（P  <0.05）。在110 d和150 d时，CK茎叶的¹³ C分配率最高（P  <0.05）。W ₂的生物量在70 d时最高，但根冠比和根干重在后期逐渐低于CK和W ₁处理，分别比CK和W ₁处理降低28.4％和32.2％。在2019年测试的第150天W ₁（P  <0.05）。W的产量₁用CK（比较由33.3-34.9％显著增加P  <0.05），但瓦特₂只有一个增加的产量的14.5-20.7％（P 相比CK <0.05）（P  <0.05）。W ₂的灌溉水利用效率比CK和W ₁处理的分别低59.4–61.8％和39.1–43.5％（P <0.05）。总之，这些结果验证了田间甘薯中期水管理模型，对于指导甘薯的实际生产和增加甘薯的潜力具有重要意义。