Different straw lengths and burial modes affect the salt distribution in coastal saline soil and the regulation of salt stress resistance in tomato

Aims Soil salinization poses a significant threat to global agricultural development. To enhance the effectiveness of saline soil improvement, the study innovatively utilized a combination of powder straw interlayer and topsoil mixing for straw returning to the field. Methods A tomato pot experiment was conducted to compare the effects of different straw lengths (S ₅₀ : 50 mm, S ₁₀ : 10 mm, S ₂ : 2 mm) and burial modes (W _i : interlayer, W _m : topsoil mixing, W _im : interlayer and topsoil mixing) on the soil salt distribution, tomato root biochemical indexes, fruit yield and dry matter weight of above-ground. Results The study found that: (1) The salt distribution was significantly influenced by the method of straw returning. Straw burial mode had a greater impact than straw length. (2) The S ₅₀ W _im , S ₁₀ W _im , and S ₂ W _im treatments exhibited more significant differences on the vertical non-uniform distribution of salt, thereby promoting the regulation of tomato roots in response to salt stress and effectively mitigating its adverse effects. (3)The S ₂ W _im treatment can significantly improve tomato fruit yield and dry matter weight of above-ground. Compared to the CK treatment, tomato fruit yield and dry matter weight of above-ground increased significantly by 89.03% ( P  < 0.05) and 59.28% ( P  < 0.05), respectively. Conslusion It was concluded that the straw returning method that combined a 2 mm straw interlayer and topsoil mixing (S ₂ W _im ) can effectively optimize the salt distribution of coastal saline soil, promote the regulation of tomatoes to salt stress, alleviate the adverse effects of salt stress, and ultimately improve tomato fruit yield.