## 4 Discussion

Table 5: Principal components, membership functions, comprehensive evaluation values (D), and rankings for different treatments. [PERSON] et al. [5] and other studies. In addition, degradation membranes cover soils with higher fast-acting N content than ordinary membranes [35] due to environmental conditions and differences in the material of the membranes themselves [37]. In the experimental study of degradable mulches, [PERSON] et al. [24] revealed an increase in total nitrogen content and no difference in organic matter content in the soil covered by degradable mulches. Nonetheless, [PERSON] et al. [5] suggested that degradable mulches and percolating mulch also contributed to the increase in organic matter content; the crops studied and the test sites were different between the two, resulting in a large difference. In contrast, the present study concluded that both degradable and permeable mulch mulches covered soils had lower total nitrogen and organic matter contents than regular and overlay mulch mulches, and the opposite conclusions reached by the two can be presumed to be due to differences in the soil environment, crop species, and management conditions. In the present study, soil enzyme activities varied considerably among treatments, indirectly reflecting the altered soil environment due to different mulch coverings. The black biodegradable mulch had a significant promotion of sucrose and cellulase activities in the soil, similar to the results of [PERSON] et al. [38] on maize and [PERSON] et al. [24] on wheat. This might be derived from its degradation products and improved soil permeability. The black-and-white combined ground mulch cover soil has elevated urethanogenicity, which is related to the possible species structure given the black-and-white characterization of its membrane. [PERSON] et al. [39] reported that the overlay mulch could raise the temperature as a way to increase the enzyme activity, while too high a temperature could inhibit the enzyme activity. Moreover, their results demonstrated that the special structure of the black-and-white combined ground mulch provided an environment in which the soil urease was more adapted to survive, and therefore the enzyme activity increased. Additionally, the black-and-white combined ground mulch had a significant effect on the elevated phosphatase activity owing to temperature, moisture, and bacterial population [40]. The experimental study of overlay mulch suggested that this may still be associated with the black-and-white structure of the black-and-white combined ground mulch. Therefore, the mechanism of the regulation of the soil environment by the black-and-white combined ground mulch should be further explored. Two common mulches and black-and-white combined ground mulch were covered with higher soil peroxidase activity than degraded and permeable mulches, ascribed to the low temperature of the test site. [PERSON] et al. [41] revealed that soil peroxidase activity was enhanced during the higher temperature production season. In this experiment, both the permeable membrane and the degraded membrane had holes on the surface that were hollow or cracked, resulting in lower soil temperatures and less enzyme activity at low temperatures compared to the regular mulch membrane with better sealing and insulation properties, as well as the overlay membrane. Mulch cultivation is effective in improving water and nutrient utilization relative to open fields [42; 43]. In a study of corn covered with different mulches, [PERSON] et al. [5] concluded that the water use efficiency and fertilizer bias productivity of biodegradable mulches were higher than those of permeable and ordinary mulches, while the lowest water use efficiency and fertilizer bias productivity were discovered for white common mulch and black common mulch, consistent with the findings of our study. There is little research on water utilization and fertilizer bias productivity of degradable and permeable membranes. This is speculated to be related to the permeability of the membranes.