Objective Using tomato as the main crop, this study evaluates the effects of intercropping with Allium plants on tomato plant growth, fruit yield and quality, and the occurrence of blossom-end rot, with the aim of providing a theoretical basis for promoting diversified ecological planting patterns.

Method A field experiment was conducted in a greenhouse. Tomato monoculture was used as the control (CK), and four intercropping treatments were established: tomato/potato-onion (T1), tomato/garlic chives (T2), tomato/scallion (T3), and tomato/garlic (T4). Through agronomic trait investigation, soil physicochemical properties measurement, fruit yield and quality analysis, and assessment of blossom-end rot occurrence, the effects of different intercropping systems on tomato growth, development, yield, and quality were examined.

Result Compared with CK, T2, T3, and T4 significantly reduced soil pH and electrical conductivity, while all intercropping treatments significantly reduced soil bulk density and increased available phosphorus content. Treatments T1, T3, and T4 significantly increased soil alkaline hydrolyzed nitrogen and organic matter content, whereas T2 and T3 significantly increased soil available potassium content. All intercropping treatments significantly promoted tomato growth and dry matter accumulation, with T3 showing the most remarkable effect, increasing total plant dry weight by 70.53%. Nutrient uptake (N, P, K, Ca) was significantly enhanced, with the most pronounced increase in calcium absorption (35.49%～78.18%). Fruit quality was noticeably improved: soluble protein, soluble sugar, lycopene, and vitamin C contents increased by 6.56%～23.16%, 6.21%～15.74%, 13.15%～24.76%, and 11.56%～21.57%, respectively. Yield per mu increased significantly by 4.83%～23.78%, and the incidence of blossom-end rot was reduced by 42.19%～57.81%. Correlation analysis indicated that plant nutrient content was significantly positively correlated with growth indicators, fruit quality, and yield, but significantly negatively correlated with soil pH, electrical conductivity, bulk density, and blossom-end rot incidence. The incidence of blossom-end rot was significantly positively correlated with soil pH, electrical conductivity, and bulk density, and significantly negatively correlated with plant calcium content.

Conclusion Intercropping tomato with Allium plants is an effective ecological planting pattern that can improve the rhizosphere nutrient environment, promote nutrient absorption (especially calcium), enhance physiological activity, improve fruit quality and yield, and effectively reduce the occurrence of blossom-end rot. This study provides a reliable technical approach for green and sustainable vegetable production.