In-situ straw return, combined with plastic film use, influences soil properties and tomato quality and yield in greenhouse conditions

To address the challenge of disposing vegetable waste in greenhouses while mitigating white pollution associated with the use of conventional polyethylene film, we compared polyethylene (PE) film with two types of fully biodegradable film in both straw-return and no-straw-return treatments. We systematically investigated the effects of mulching on soil properties, film degradation, and tomato quality and yield. The results showed that the humic acid biodegradable film with straw-return (FZS-SR) increased the contents of lycopene, vitamin C (Vc), and soluble sugars in tomato fruit by 20.77%, 16.68%, and 25.89%, respectively, and decreased the total acid content by 8.46% compared to polyethylene film with no-straw-return (PE-NR). Additionally, FZS-SR enhanced the relative abundance of soil bacteria and fungi in Chloroflexi and Basidiomycota, while reducing the relative abundance of pathogenic fungal groups. Moreover, the biodegradable film degraded 15 days earlier in the straw-return treatment, with significantly higher characteristic peaks in Fourier transform infrared spectral analysis compared to no straw-return treatment. In a greenhouse, the straw-return model accelerated the degradation rate of biodegradable film. In summary, our results indicate that using humic acid biodegradable film with straw-return is an effective and sustainable cultivation method, improving tomato quality and yield. This approach offers insights for addressing residual plant and film pollution in vegetable production.