The degradable time evaluation of degradable polymer film in agriculture based on polyethylene film experiments

Abstract

Abstract Popularly, the application of biodegradable polymer film can resolve polyethylene (PE) film residual “white pollution” but it is unclear when the degradable film begins to degrade in different regions. To solve these issues, a total of 32 papers on the subject of the relative film coverage durability (RFCD) on positive covering effect from papers published before July 2019 were selected and analyzed by meta-analysis. The results showed that the tobacco relative yield (RY), relative profit (RP), and relative fine and medium (RFM) ratio improved by 11.2%, 12.9%, and 12%, respectively, under fully covered compared with the uncovered tobacco in the whole growth period. The RY0.33<RFCD<0.66 and RP0.33<RFCD<0.66 of removed PE treatments significantly improved by 4.3% and 4.0%, respectively, compared with the fully covered treatments. The RFM did not show significance with the fully covered treatments. The RY0.33<RFCD<0.66 was the highest in the low altitude (less than 1,000 m) region; however, the RY under the fully covered treatments was the greatest in the high altitude (more than 1,000 m) region. Random effect analysis showed that the model between RFCD and RY was RY = 1 + 0.275 × (1 − RFCD) – 0.357 × (1 − RFCD)2, and the RYmax(1.053) was reached with RFCD = 0.62 (removed PE after covering for 80 days) in the high-altitude region. In the low altitude region, RFM = 1 + 0.205 × (1 − RFCD) − 0.246 × (1 − RFCD)2, and the RFMmax(1.043) was obtained under the treatments with RFCD = 0.58 (removed PE after covering for 75 days). The findings determined the optimum film (PE) covering period of tobacco and provided a crucial theoretical basis for the degradable polymer film material design, synthesis, and manufacturing in different regions.