Eco-friendly biodegradable PBAT/PLA mulch films are attracting increasing interest in sustainable agricultural production. However, currently, little is known about the service life for the PBAT/PLA mulch films. Herein, PBAT/PLA mulch films are subjected to indoor UV-accelerated degradation (UAD) experiments and field cultivation environment degradation (CED) experiments to systematically investigate the relationship between UAD and CED processes. Results demonstrate that 10 days of indoor UAD treatment corresponds to around 120 days aging under outdoor CED conditions. Using eight PBAT/PLA evaluation indicators (haze, elongation at break, tensile strength, gel content, light transmittance, polydispersity index, M n , M w ), we established a service life prediction model for PBAT/PLA mulch films based on short-term indoor UAD experiments, which could accurately estimate the long-term service life of the mulch films in the field. In particular, using the haze value, near-perfect correlation (R 2 = 0.995 for eq. 1 and R 2 = 0.993 for eq. 2) was found between CED days and UAD days. The establishment of these reliable predictive models for the service lifetime of PBAT/PLA mulch films will avoid the undesirable premature breakdown during crop growth, thus fostering end-user confidence in eco-friendly biodegradable mulch films.

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Mechanical construction will put influence on the biological characters of reclaimed soils, as well as the soil quality. In order to explore the changing rule of soil microbial quantity and respiratory capacity under different construction machineries and rolling times, and find the optimal processing conditions, an experiment was set up and a simulation experimental area was chosen, in which we simulated the main types of reclamation in coal mine area. After 2 years' natural aging, we collected surface soil samples (0-20 cm) that can be used for experimental analysis. The result shows that changing rules of soil biological factors are different with different construction machineries, and soil properties are closest to the normal soil when adopting the combination of ''crawler dozer 9 5 compaction times'' and ''dump truck 9 3 compaction times'', which shows that the soil quality is better under this condition.

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