设施内PBAT/秸秆基地膜降解特性及对番茄生长的影响

为了探究降解地膜在设施内的应用效果，该研究选取PBAT/秸秆基全生物降解地膜为研究对象，同时设立PE地膜组和不覆膜组进行对比，将其应用于江苏地区设施番茄生产。采用傅里叶红外光谱仪、X射线衍射仪、热分析仪、接触角测量仪、扫描电子显微镜和万能材料试验机探究地膜在降解过程中微观结构与形貌、力学强度的变化特性，同时测定地膜在应用过程中对番茄植株株高、茎粗和产量的影响，并进行地膜产品的综合效益分析。结果表明，PBAT/秸秆基全生物降解地膜在120 d覆膜期内物理化学性质发生一系列变化，逐步发生了降解。PE地膜在120 d覆膜期内表征和力学性能均没有明显变化，说明无降解行为发生。降解地膜对番茄生长的促进效果与PE地膜相当，且均优于不覆膜组。降解地膜组和PE地膜组的番茄果实折合667 m2产量，分别比不覆膜组高出13.5%和15.0%。地膜综合效益分析表明，PBAT/秸秆基全生物降解地膜的综合效益较佳。因此，PBAT/秸秆基全生物降解地膜应用于江苏地区设施番茄栽培的效果良好，后续可在设施内外其他作物上进行推广试用。

PBAT/straw based mulching film degradation characteristics and effect on tomato growth in facilities

Polybutylene adipate terephthalate (PBAT) has emerged as a potential biodegradable mulching film in recent years. Taking the tomato cultivation as the research object, three treatments were selected for the biodegradation characteristics, including the ordinary PE mulching film (T1), PBAT/ straw-based biodegradable mulching film (T2), and non-mulching film (T3) in Jiangsu Province of China. The microstructure, morphology, and mechanical strength of the film were characterized during degradation. Meanwhile, the effects of mulching film on the tomato plant height, stem diameter, and yield were clarified to determine the comprehensive benefits of biodegradable mulching film. The results show that there were a series of changes in the physical and chemical properties of the PBAT/straw-based biodegradable mulching film during the 120 d mulching period. The Fourier infrared spectrum showed that the molecular chain of the degradable mulching film was broken under the action of soil microorganisms, light, and water. The X-ray diffraction pattern exhibited that the crystalline area of degradable mulch was destroyed gradually, whereas, the amorphous area increased relatively. Thermogravimetric analysis indicated that there were a few Tmax changes, T0 increase, and a decrease in the carbon residue rate, indicating the thermal properties of the degraded mulching film. The water contact angle confirmed that the degradable mulching film was degraded in the field. Scanning electron microscopy (SEM) images illustrated that there was an uneven degradation of mulching film. The tensile strength and elongation decreased gradually at the break of the degradable film, as the film covering time increased. The mechanical property test verified that the PBAT/ straw-based biodegradable mulching film was degraded gradually in the field with a slow degradation rate after 120 days. Moreover, there was a better effect of degradable mulching film on the tomato growth, compared with the conventional PE and non-mulching film group, in terms of the plant height and stem diameter of tomato plants. The yield of tomato fruit in the degradable and the PE mulching group was equivalent to 667 m2, which was 13.5% and 15.0% higher than that in the non-mulching film group, respectively. The excellent ecological benefits and the higher recovery cost-saving were achieved for the PBAT/straw-based fully biodegradable mulching film, although the product cost was relatively high. In general, the PBAT/ straw-based fully biodegradable mulching film can be widely expected to serve a remarkable effect on tomato cultivation in the greenhouse. The degradation cycle can be further explored to accelerate the spread the promotion of the degradable mulching.