With the rapid development of the vegetable industry and the accelerating pace of population aging, mechanization in the core production process of vegetable seedling grafting has become an inevitable trend. To address this, various vegetable grafting devices have been developed globally. However, most existing equipment exhibits limited automation and is prone to damaging young plant stems during operation. To effectively reduce seedling injury, improve grafting quality, and increase success rates, this study focused on tray seedlings of cucurbitaceous vegetables as grafting subjects. Based on the bud grafting method, we conducted mechanistic analysis and structural design for the cutting module, the integrated clamping and grafting mechanism, and the clip supply and binding system. Experiments were carried out at the Protected Agriculture Demonstration Base in Ke Township, Yecheng County, Kashgar Prefecture, Xinjiang. The study adopted the multiple-group repeated experiment verification method, and completed verification through cutting tests and grafting efficiency tests. Specifically, 250 rootstocks and 250 scions were selected for the cutting tests, while 500 rootstocks and 500 scions were selected for the grafting efficiency tests; both tests were divided into 5 groups, and the data were analyzed using descriptive statistical analysis. Cutting trials and clamping performance tests demonstrated that the designed mechanism improves the precision of alignment between rootstock and scion cuts while minimizing potential damage during clamping, confirming the rationality of the design. The overall performance was further validated in grafting trials using Qingyan rootstock No. 1 pumpkin and Yongtian No. 5 melon as scions. Results showed that with rootstock and scion cutting angles set at 30° and 25°, respectively, and corresponding cut surface lengths of 6.34 ± 0.18 mm and 6.29 ± 0.14 mm, the device achieved a grafting efficiency of 1400 plants per hour with an average success rate of 90%, and no obvious stem damage was observed during the clamping process. These results demonstrate that the proposed grafting machine design is effective in enhancing both grafting efficiency and quality.

To clarify the responses of tomato stem sap flow to soil water availability and microclimate in an extremely arid region, three irrigation treatments were established in an overwintering solar greenhouse in Kashgar, Xinjiang. The soil at the experimental site is sandy loam: full irrigation (CK, 80–90% field capacity), mild deficit irrigation (T1, 70–80%), and moderate deficit irrigation (T2, 60–70%). Stem sap flow, root-zone soil moisture, and canopy microclimate were continuously monitored to characterize sap flow dynamics, environmental correlations, and time-lag responses across growth stages and weather conditions. Stem sap flow exhibited a clear unimodal diurnal pattern under all treatments. On sunny days, the peak sap flow of CK decreased from 39.62 cm h⁻¹ during the flowering and fruit-setting stage to 20.98 cm h⁻¹ during the mature harvesting stage. Sap flow dynamics under T1 were generally similar to those under CK, whereas T2 showed a marked reduction under high radiation and vapor pressure deficit conditions. Sap flow lagged behind solar shortwave radiation by approximately 30–60 min. Its association with microclimate also varied with growth stage and weather conditions, with solar radiation showing a strong correlation during the flowering and fruit-setting stage and air temperature becoming more closely associated with sap flow during the mature harvesting stage. Compared with CK, T1 reduced irrigation water use by 11.5–30.1% and yield by 10.7–16.5%, while increasing irrigation water use efficiency by 1.2–19.0%. Under the present experimental conditions, maintaining root-zone soil moisture at 70–80% field capacity provided a favorable trade-off among plant water transport, yield, and water saving. Stem sap flow may therefore serve as a supplementary physiological indicator for irrigation management in solar greenhouse tomato production.