中国可降解膜覆盖对玉米产量效应的Meta分析

可降解膜是解决农业生产中地膜残留污染的有效措施,但覆盖可降解膜的作物产量效应仍存在较大分歧.该研究以玉米为研究对象,分别以不覆盖和覆盖普通地膜作为覆盖可降解膜的对照,通过检索已发表的相关田间试验数据,利用Meta分析方法定量研究覆盖可降解膜对玉米的产量效应和影响因素.结果表明,在可降解膜和不覆盖组合中,覆盖可降解膜的玉米产量较不覆盖平均提高17.8%(95%置信区间14.8%~20.9%);该组合不存在发表偏倚和极端值.可降解膜和普通地膜组合存在发表偏倚,校正前覆盖可降解膜的玉米产量显著低于覆盖普通地膜(平均相差1.8%),校正后二者差异不显著(置信区间-0.9%~2.7%);该组合也不存在极端值.与不覆盖和覆盖普通地膜相比,覆盖可降解膜的累计平均产量效应均随时间趋于稳定.近5 a来,覆盖可降解膜与覆盖普通地膜的玉米产量差异和变幅均较2000—2010年有所减小.在高海拔、低气温区域,平作和使用0.008 mm厚度降解膜时,更有利于提高可降解膜的增产效应.该研究可为降解膜的大规模推广应用和开发研制提供依据.

Meta-analysis on effect of degradable film mulching on maize yield in China

Plastic film mulching has become an important cultivation practice in agricultural production in China. However, the residuals of plastic film in soil continuously increase with its considerable application. These residuals cause a series of negative effects on environment and land. Degradable film is recognized as a feasible choice to replace plastic film. This study aimed to reveal the influence mechanism and comprehensive effects of degradable film mulching on maize yield. A total of 28 papers were selected from published articles before November in 2016, and meta-analysis was applied. Critical information was obtained from each study, including experimental site, planting pattern, site altitude, average annual precipitation, average annual temperature, experimental duration, degradable film thickness, degradable film types, and maize yield. The collected data were divided into 2 groups. In the first group, no mulching was taken as the control for degradable film mulching, including 24 available comparison pairs. In the second group, plastic film mulching was taken as the control for degradable film mulching, including 24 available comparisons. The main steps included heterogeneity test, comprehensive effect size calculation, publication bias test and correction, sensitivity analysis, cumulative meta-analysis, meta regression analysis and influence factor analysis. The results showed that in the first group, degradable film mulching averagely increased maize yield by 17.8% compared with no mulching. There were no publication bias and extreme value. The cumulative yield increasing effect of degradable film mulching trended to be stable over time. Biodegradable film had a stable maize yield than photo degradable film and photo-biodegradable film. The degradable film with 0.008 mm thickness had a significantly higher maize yield than that with 0.006 mm. The yield increasing effect of degradable film mulching trended to be smooth during years of 2002-2015 with a range of 13.4%-17.3%, and was the highest (29.0%) in Gansu Province. There was a publication bias but no extreme value in the second group. Before publication bias was corrected, the maize yield was significantly lower under degradable film mulching than that under plastic film mulching. However, this difference was not significant after publication bias correction. The maize yield was not significant between degradable film mulching and plastic film mulching in regions, where altitude was higher than 1000 m, average annual temperature was lower than 10 ℃, and flat planting and 0.008 mm film was used. The difference and variation of maize yield under degradable film mulching and plastic film mulching decreased in the last 5 years. In summary, degradable film mulching could achieve a high maize yield in regions with high altitude and low temperature, and flat planting using 0.008 mm film. This research can provide valuable information for the development and large-scale application of degradable film.