Effects of PBAT-PLA based biodegradable film mulch on soil environment, onion production, and the growth of following crop

This study was conducted to evaluate the soil properties, growth, and yield of onions (Allium cepa L.) in response to non-mulching (NM), polyethylene film (PEF) and biodegradable film (BF) mulching in a commercial farm from 2022 to 2023. In addition, there was to assess the effects of the residual films on the ecophysiological properties of corn (Zea mays L.) crop growth and the soil in 2023. Approximately 5% degradation of the BF film occurred 210 days after transplanting (DAT), increasing light penetration into the films and decreasing film weight maintenance. Soil minimum- and maximum moisture content and temperatures were not significantly different among the treatment plots in February, with increased maximum soil temperatures occurring in the PEF plots in May. The soil concentrations of NO₃⁻, Ca, and Mg increased in the PEF and BF treatment plots, with no significant differences in weed vegetation. Onion bolting was lower for PEF (4.8%) and BF crops (3.0%), with a higher plant lodging of approximately 60.0% compared to NM crops (30.0%). BF treatment significantly increased the number of leaves at 150 DAT and leaf weight at 180 DAT, extended the bulb length at 120 and 210 DAT, and enhanced the weight of BF and PEF onions. The total onion production per hectare based on the very large size was considerably higher in the BM treatment (39.9 ton per ha), PEF (37.2 ton), and NM (11.1 ton). In the subsequent cultivation of corn crops after harvesting onions, film visual degradation was observed for BF to approximately 20% at 60 DAT, with a decrease in film weight maintenance and an increase in light penetration due to warm temperatures and high radiation from July to September. Soil NO₃⁻ concentrations were increased by the BF treatment, with increased soil pH levels in the PEF treatment plots at 0 and 30 DAT in the corn field. The BF treatment increased the weight of leaves and ears and enlarged the corn ear diameter, with a high sugar content in corn kernels. The PEF and BF plot s resulted in a higher liquid phase and lower air phase compared to the NM plots, resulting from a high weed density at 90 DAT. The BF mulch with an appropriate degradation rate did not negatively impact the productivity of both onions and the subsequent corn crop, and soil physico-chemcial properties without the adverse effects of residual films in the soil system.