Plastic film mulching is a common practice to increase vegetable yields. However, the effects of plastic mulch films on different vegetable fields remain largely unknown. In the current study, biodegradable mulch films (BDMs) and polyethylene mulch films (PEMs) were used to explore their effects on three vegetable fields (broccoli, chili pepper and garlic). Compared with bare soil, both BDMs and PEMs could effectively maintain higher exchangeable potassium contents in rhizosphere soil, and significantly increase various soil properties and microbial abundance both in rhizosphere and non-rhizosphere soils. In terms of yields, the treatments of BDMs and PEMs effectively increased broccoli, chili pepper and garlic yields by 17.6–19.0%, 21.3–23.3% and 26.0–29.5%, respectively, when compared with the bare soil. Our initial characterization provided insights into the effects of BMDs and PEMs on soil properties, yields and diversity of rhizosphere and non-rhizosphere microbial communities in three vegetable fields.

In present-day mechanized garlic seeding, high missing rates and low qualified percentages of single seeds are common problems; thus, a finger clip plate garlic seed-metering device was designed in this study. First, the structure and working principle of the seed-metering device were studied. Subsequently, the critical component parameters of the seed-metering device were determined using theoretical calculations; then, EDEM software was used in single-factor simulation experiments to analyze the effects of opening the diameter of the seed-collecting spoon, the operating speed of the seeding tray, and the population number on the seed-filling performance. Finally, a Box–Behnken center combination experiment was conducted with the population, opening the diameter of the seed-collecting spoon, and rotating the speed of the seeding tray as experiment factors, with the single-seed filling rate, qualified percent, and missing rate as evaluation indicators. A three-factor and three-level orthogonal test was conducted to establish the mathematic regression model of the experiment factors and evaluation indicators, as well as to realize the parameter optimization. After rounding, the laboratory validation test was carried out with 240~280 seeds, a 26 mm seed scoop-opening diameter, and a 28 r/min operating speed. The average qualified rate, missing rate, and reply rate of single seeds were 91.86%, 2.71%, and 5.43%, respectively, which is basically consistent with the forecast results of regression model.

The long-term use of polyethylene mulch (PEM) films can cause plastic film residual pollution that has an adverse effect on soil health and crop quality. To address this issue, poly(butylene adipate-co-terephthalate) (PBAT), an aliphatic–aromatic copolyester, is widely used in the production of commercially biodegradable plastic mulch (BDM) films. The use of BDMs can alleviate soil plastic pollution and reduce the labor cost of retrieving plastic film residues from the field. The effects of BDM and PEM on the agronomic and nutritional quality traits of cabbage cultivar ‘Sugan No. 35’, as well as the physicochemical properties and microbial communities of the soil were analyzed during two consecutive years of the experiment. No significant difference was observed in the cabbage agronomic and nutritional quality traits among three mulching treatments. Nonetheless, the mulching and degradation of BDM reduced the pH value and increased the organic matter content of the soil samples compared with PEM mulching. In the soil bacterial and fungal communities, Proteobacteria and Ascomycota were the most abundant bacterial phylum and fungal phylum across all the soil samples, respectively; the use of BDM increased the relative abundance of soil Proteobacteria and Ascomycota compared with PEM mulching. The overall cost of BDM mulching was much lower than that of PEM mulching during the cabbage production.