Effects of Biodegradable-Film Mulch and Residue on the Growth and Yield of Pepper and Onion Cultivated under a Two-year Crop Rotation Scheme

다국어 초록 (Multilingual Abstract)

This study was conducted to evaluate the effects of biodegradable (BD) films mulched in crop rotation fields, specifically pepper from April to September and onion from October to May, as well as the effects of the film residue on soil mineral nutrition and crop growth outcomes in South Korea. Five treatments were used: non-mulching (NM), polyethylene (PE) film mulch, and three BD film mulches (referred to as F, H, and E). Film F was made using polybutylene adipate-co-terephthalate (PBAT) and polylactic acid (PLA); film H was made using PBAT+PLA; and film E was made using PLA+starch. The pepper field showed greater levels of degradation of all BD films, in particular for the H and F films, compared to the films in the onion field under exposure to excessively warm temperatures and high rainfall amounts during the cultivation period. The F film-mulched pepper plots had the lowest soil moisture level of ‒47.0 kpa on August 1, 2023 owing to high biodegradability, and the values for the onion plots remarkably in April of 2024. Seasonal soil electrical conductivity decreased in both the pepper and onion plots, with significantly higher levels in the mulch plots than in the NM plots in the pepper field at 0 and 30 days after transplanting (DAT). In most cases, no significant differences were observed in the soil mineral nutrient levels between the treated pepper and onion plots. The stem height increased in peppers grown under PE film mulching at 60 DAT and under F film mulching at 120 DAT. The number of pepper leaves increased with the BD mulching treatments at 60 and 90 DAT, with higher SPAD readings observed at 60 DAT. The greatest stem diameter and leaf fresh weight values were observed at 180 DAT in the E film-mulched onions. All mulch treatments increased the number of pepper fruits. The H film mulching treatment produced a large number of bulbs and resulted in the highest yield of 61.1 ton ha-1, followed by mulching with the E (59.4 ton), PE (48.5 ton), F (43.3 ton), and NM (34.0 ton) films. Breakdown of BD films, particularly the F film, occurred on topsoil with considerable disintegration at a depth of 10 cm in the onion field after the completion of one crop rotation cycle. Adverse effects from the remaining BD residue were not observed for the subsequent period of onion growth, and the H and E films were recommended to preserve soil health and improve crop productivity of warm- and cool-season vegetables.