地膜厚度对作物产量与土壤环境的影响

农用地膜(以下简称地膜)已成为我国干旱、冷凉地区土壤增温、保墒和作物增产的重要措施。为摸清我国地膜厚度应用现状,研究地膜厚度对作物产量和土壤环境的影响,2011年,在全国范围内针对棉花、玉米、马铃薯、花生等主要覆膜作物分别布置172、99、30、58个调查点,采用问卷调查的方法对我国地膜厚度应用现状进行系统调查。根据调查结果,2011—2013年,在新疆、甘肃、内蒙古、山东4省分别针对以上4种作物,设置不同地膜厚度处理,系统分析了地膜厚度对土壤温度和含水量、作物产量、经济效益以及地膜残留强度等的影响。研究结果表明,我国主要覆膜作物现用地膜厚度较薄,96.7%的地膜厚度集中在0.004~0.008 mm之间。增加地膜厚度能够提高土壤温度和含水量,但对不同作物的产量影响不同;随着地膜厚度增加(0.004~0.012 mm),棉花和玉米产量不断增加,而马铃薯和花生产量先增加后减少;地膜厚度对作物经济效益有一定影响,但处理间无显著性差异(P0.05)。地膜厚度显著影响地膜残留强度(P0.05),除了马铃薯外,其余作物地膜残留强度和地膜厚度均呈显著负相关关系(P0.05)。综上所述,增加地膜厚度对于我国主要覆膜作物有一定的增产作用,但增产幅度有限,而在残膜回收的基础上增加地膜厚度能够显著降低地膜残留强度。为应对我国农田地膜残留问题,建议我国地膜厚度标准提高至0.010~0.012 mm较为适宜。

Effect of film thickness on crop yield and soil environment

Film mulching in cropland is a key agricultural technique for increasing soil temperature, conserving soil moisture and improving crop yield in the arid and cold regions of China. This study aimed to inventory the application status of different thicknesses of films in China, and to investigate the effects of film thickness on crop yield and soil environment. Film application status was obtained by a national questionnaire-survey on 172 cotton fields, 99 maize fields, 30 potato fields and 58 peanut fields in 2011. Based on the survey, film thickness was categorized, and filed experiments were conducted from 2011 to 2013 to investigate the impacts of representative thicknesses of film on soil temperature, soil moisture content, crop yield, economic efficiency and the amount of residual film in Xinjiang, Gansu, Inner Mongolia and Shandong respectively for cotton, maize, potatoes and peanuts.Results showed that the most of China''s mulching film were ultrathin, and 96.7% of the films surveyed had a thickness of 0.004~0.008 mm.Enhancing film thickness managed to improve soil temperature and moisture status, but it resulted in different yield responses depending on crops.An increase of film thickness from 0.004 to 0.012 mm increased yields of cotton and corn but decreased potato and peanut yields. Film thickness tended to influence farm economy, but the difference between treatments was no significant(P<0.05). Film thickness influence damounts of residual in the soil significantly(P<0.05). For all crops except potato, the amount of film residual was significantly negatively correlated with the film thickness(P<0.05). Despite a variation of effects on crop yields, increasing film thickness could reduce the strength of residual films in the soil, which would largely benefit collection of residual films.Therefore, we suggest an increase of the national standard of film thickness, for example to 0.010~0.012 mm as suggested by this study, to solve the severe problem of soil film residual in China.