Degradation characteristics of biodegradable film and its effects on soil nutrients in tillage layer, growth and development of taro and yield formation

This study investigated the degradation characteristics of different biodegradable film and its effects on soil nutrients in tillage layer, growth and development of taro and yield formation . Field experiment with biodegradable films, including poly-(butylene adipate-co-butylene terephthalate) PBAT, (poly-carbon dioxide) PCO2, (poly propylene carbonate) PPC, as well as common mulch film (CK1) and uncovered mulch film (CK2) were conducted on Longxiang taro in 2020 and 2021 respectively. The degradation rate of the three biodegradable films was PBAT > PPC > PCO2. Compared with CK1, the alkali-hydrolyzed N of PBAT at the growth stage and fruiting stage significantly increased in 2020 and 2021, respectively (both, P < 0.05 ). The average content of available P of PPC at seedling stage was higher than that in PCO2, and CK1 was significantly decreased compared with that in CK2 (all, P < 0.05 ). The content of soil available K and organic matter in different growth stages of taro in all film mulching treatments were decreased in comparison to CK2. Moreover, compared with CK2, PCO2 biodegradable film significantly increased plant height at seedling and growth stage, stem diameter at growth stage, and leaf area index at fruiting stage (all, P < 0.05 ). Similarly, the yield of mother and filial bulbs of PPC, PCO2 and PBAT were significantly higher than those of CK2 in 2020 and 2021, respectively (all, P < 0.05 ). However, no significant differences were found in starch, polysaccharide and protein contents among different treatments. The three biodegradable films, especially PCO2, can significantly affect soil nutrient content, promote plant growth and improve taro yield.