不同地膜的降解性能与力学特性及其对南瓜生长的影响

Degradation and mechanical properties of different mulch films and their effects on pumpkin growth

【目的】明确不同降解地膜对南瓜生长的影响及其降解性能和力学特性的变化特征。【方法】通过田间南瓜栽培覆膜试验,探究黑色PE地膜(CK)、白色降解地膜(T1)、黑色降解地膜(T2)和黑色二氧化碳基降解地膜(T3)在南瓜生育期内的地膜伸长率、断裂力值等力学指标变化趋势,以及对南瓜植株生长的影响。【结果】随着覆膜时间增加,在重要的生育期通过对力学性能检测和降解程度分析发现,不同地膜力学特性都呈下降趋势,3种降解膜各项力学指标值下降幅度最明显。其中,T1处理地膜各项力学指标初始值均比T2和T3高,在南瓜生育期内的降解程度弱于T2和T3;T2和T3各项力学特征值比较趋近,膜的降解程度等级一致。通过相关性分析得出降解膜力学特性与降解程度呈负相关,降解程度随力学特征值下降而增加;CK覆膜处理植株叶片SPAD值和叶绿素a、b含量高于3种降解膜,具有较强的光合能力,因此植株叶片数、面积和蔓长的生长发育情况表现较好;黑色降解膜(T2)和黑色二氧化碳基降解膜(T3)处理南瓜的可溶性固形物和Vc含量增加,对南瓜总体品质有提升作用,二者的南瓜产量趋近并与CK无明显差异。【结论】降解地膜力学特性下降会加快降解速率并影响地膜辅助生产的性能,覆盖黑色降解膜和黑色二氧化碳基降解膜可以提升南瓜品质,且南瓜产量与覆盖黑色PE膜无显著差异。鉴于降解膜在农业生产中的环保性,其替代普通PE膜进行农作物以及蔬菜生产具有可行性。

【Objective】The present paper aimed to clarify the effects of different degradation films on the growth of pumpkin and the charac⁃teristics of the changes in the degradation performance and mechanical properties of the films.【Method】We investigated the trends of me⁃chanical indexes such as film elongation and breaking force values of black PE film(CK),white degradable film(T1),black degradable film(T2)and black carbon dioxide⁃based degradable film(T3)and their effects on the growth of pumpkin plants during the reproductive period of pumpkin through the field mulching test.【Result】With the increase of coating time,it was found that the mechanical properties of different membranes showed a decreasing trend through the mechanical properties testing and degradation degree analysis during the important fertility period,and the values of the mechanical indexes of the three degradable membranes showed the most obvious decreasing magnitude.Among them,the initial values of all mechanical indexes of T1 treated membranes were higher than those of T2 and T3,and the degradation degree was weaker than that of T2 and T3 during the reproductive period of pumpkin;The values of all mechanical characteristics of T2 and T3 were relatively similar,and the degradation degree of the membranes was of the same grade.Through correlation analysis,it was concluded that the mechanical characteristics of the degraded film were negatively correlated with the degree of degradation,and the degree of deg⁃radation increased with the decrease of the mechanical characteristic values;The SPAD value,chlorophyll a and b contents of the leaves of CK mulching treated plants were higher than those of the three degraded films,and they had stronger photosynthetic capacity,so the growth and development in the number of leaves,area and length of the vine showed better performance.Black degradation film(T2)and black car⁃bon dioxide⁃based degradation film(T3)treated pumpkins had increased soluble solids and Vc contents,which had an enhancement effect on the overall quality of pumpkin,and the pumpkin yields of the two converged and were not significantly different from those of CK.【Con⁃clusion】Degradation of the mechanical properties of the degradable film will accelerate the rate of degradation and affect the performance of film⁃assisted production,covering the black degradable film and black carbon dioxide⁃based degradable film can be made to improve the quality of pumpkin quality,and pumpkin yield is not significantly different from the covering of black PE film.In view of the environ⁃mentally friendly nature of degradable films in agricultural production,it is feasible to replace ordinary PE films in crop and vegetable pro⁃duction.