Objectives To clarify the ion accumulation in tomato root zone under different cultivation substrates and liquid supply methods, in order to provide reference for the selection of tomato cultivation substrate and irrigation mode and the adjustment of nutrient solution formula.

Methods ‘Ruifen 882’ tomato was used as test material, and three cultivation substrates (coconut coir, turf, and perlite) and two nutrient delivery systems (open and closed) were used. The six treatments included: open coconut coir (OC), open turf (OT), and open perlite (OP), closed coconut coir (CC), closed turf (CT), and closed perlite (CP). Comprehensive assessments were conducted on plant growth parameters, fruit quality, yield, ion accumulation in the rhizosphere solution, water use efficiency (WUE), and partial factor productivity of fertilizers.

Results Under the same nutrient delivery system, peat substrate was found to be more favorable for enhancing tomato growth and yield. Comparatively, under identical substrate conditions, the open system promoted greater growth and yield, albeit with a reduction in fruit quality relative to the closed system. Ion accumulation, leading to an increase in the electrical conductivity (EC) of the root zone solution, was observed in both open and closed systems as the growing season progressed, with the closed system showing more pronounced ion buildup, at the end of growth, CC, CT and CP treatments reached 6.21, 6.78 and 5.73 mS/cm, respectively. Notably, in the closed system, the peak (EC) in the perlite substrate’s nutrient solution occurred significantly later than in coco coir and peat substrates, suggesting that perlite may allow for less frequent replacement of the nutrient solution. By the end of the growing period, ion accumulation in the rhizosphere solution peaked in the following order CT>CC>CP>OT>OC>OP. The contribution of different ions was ranked as K⁺, Ca²⁺, SO₄²⁻, Mg²⁺, H₂PO₄⁻. Additionally, the overall agronomic efficiency indicated that the closed system outperformed the open system in terms of WUE and fertilizer productivity. The average membership function showed that tomatoes under closed turf cultivation obtained the maximum benefit on the basis of fertilizer saving and emission reduction.

Conclusions The open liquid supply method can increase the yield of tomato, but the water demand is huge. Peat can be used as the cultivation substrate when the open liquid supply method is selected. The closed turf is more conducive to the realization of water-saving and fertilizer-saving and environment-friendly development. The effect of ion accumulation in the root zone should be paid attention to when using the closed liquid supply method. In the formula of the later nutrient solution, the closed coconut coir needs to reduce the ion content of SO₄²⁻, the closed turf needs to reduce the content of K⁺ and Ca²⁺, and the closed perlite needs to reduce the content of H₂PO₄⁻.