Objective Effects of intercropping tomato with Allium species on the growth, fruit yield and quality as well as the incident of blossom-end rot of the plants were investigated for an ecological farming practice.

Method In a field experimentation, tomato plants were monocultured (CK) or intercropped with 4 different edible Allium species including potato-onion (T1), garlic chives (T2), scallion (T3), and garlic (T4) in a greenhouse. Agronomic traits, fruit yield and quality, and occurrence of blossom-end rot of the tomato plants as well as physicochemical properties of the soil were monitored for a correlation analysis.

Result In the soil, all intercropping treatments significantly lowered the bulk density and raised the available phosphorus content. Except T1, the treatments significantly reduced the pH and electrical conductivity; and other than T2, they significantly increased the alkaline hydrolyzed nitrogen and organic matters. T2 and T3 significantly enriched available potassium. Whereas, all treatments significantly promoted tomato plant growth and dry matter accumulation, especially T3, which rendered 70.53% increase on total dry weight and significantly on uptakes of N, P, K, and most pronouncedly 35.49-78.18% Ca increases. The fruit quality was improved with 6.56-23.16% increase on soluble protein, 6.21-15.74% on soluble sugar, 13.15-24.76% on lycopene, and 11.56-21.57% on vitamin C. The fruit yield per mu rose significantly by 4.83-23.78%, while the blossom-end rot incident reduced by 42.19-57.81%. The plant nutrient content significantly correlated with the growth indicators and fruit quality and yield but negatively with pH, electrical conductivity, and bulk density of the soil as well as blossom-end rot incident on the plants. The disease occurrence also significantly correlated with soil pH, electrical conductivity, and bulk density but negatively with plant Ca content.

Conclusion For tomato farming, intercropping the plants with different varieties of Allium could significantly improve the rhizosphere nutrient environment, nutrient utilization (especially Ca), plant physiological activity, and fruit quality and yield, and at the same time, reduced the occurrence of blossom-end rot on the crop.