山西旱作区不同类型地膜对谷子产量影响及降解性能研究

为了研究山西旱作区不同类型地膜对谷子产量影响及其降解性能，在山西省朔州市布置地膜覆盖试验，设4个处理普通地膜（PE）、PLA/PBAT复合型降解地膜（PP）、PBAT全生物降解地膜（PB）、不覆膜（LD）]。结果表明：与不覆膜相比，地膜覆盖使谷子产量平均增长32.6%，但覆膜处理间差异不显著。随着覆盖时间的增加，2种可降解地膜水蒸气透过量显著增加，表现为PB膜>PP膜>PE膜。力学性能（拉伸强度、撕裂强度和断裂标称应变）显著下降，表现为PE膜>PP膜>PB膜，微观形态和化学结构变化显著，普通地膜变化不明显，微观表面粗糙度表现为PB膜>PP膜>PE膜。PB膜在保障谷子产量的同时降解效果最佳，农田残留最少，覆膜150 d后降解率达到74.8%，降解残片以<2 cm²和2~5 cm²的中小规格为主。从谷子产量、地膜物理性能、化学结构和降解残留度等方面综合评价，PBAT全生物降解地膜在确保谷子产量的同时具有良好的降解效果，可作为PE膜的替代品应用于晋北地区旱地谷子生产中。

Effects of different types of mulching film on millet yield and their degradation properties in dry farming area of Shanxi Province, China

To study the effects of different types of mulching film on millet yield and their degradation performance in a dry farming area of Shanxi Province, a mulching experiment was carried out in Shuozhou, Shanxi Province. Four treatmentsPE, PLA/PBAT complex type degradable mulch(PP), PBAT biodegradable mulch(PB), and no mulch(LD)] were set up. Results showed that the yield of millet under mulching increased by an average of 32.6% compared with that without mulching; however, there was no significant difference between mulching treatments. With an increase in mulching time, the water vapor transmittance of the two degradable mulching films increased significantly in the order:PB film > PP film > PE film. Mechanical properties(tensile strength, tear strength, and fracture nominal strain)decreased significantly in the order:PE film > PP film > PB film. Changes of microstructure and chemical structure were significant, but was not obvious in the ordinary plastic film. Surface roughness was in the order:PB film > PP film > PE film. The degradation rate of PB film reached 74.8% after 150 days of mulching, and the degradation debris of less than 2 cm² and 2~5 cm² were the main size. From the comprehensive evaluation of millet yield, physical properties, chemical structure, and degradation residual degree of film, PBAT fully biodegradable mulching film has good degradation effects on millet yield and can be used as a substitute for PE film in dryland millet production in northern Shanxi Province. K