地膜降解与土壤温度和含水量的关系及其对棉花产量的影响
Film Degradation Related to Temperature and Moisture of Soil and Its Response on Cotton Yield

为研究膜下滴灌棉田覆用降解地膜的保温保墒效果，通过田间试验，设DM1(普通聚乙烯地膜）、DM2(低降解率地膜）、DM3(中等程度降解率地膜）、DM4(高降解率地膜）4个覆膜处理，对各处理的地膜降解率、地温、土壤含水量、棉花产量进行调查测试，分析地膜不同降解率与土壤温度、含水量的相关关系。结果表明：棉花各生育期地膜降解率与产量呈负相关关系；地膜降解率与土壤温度呈线性负相关关系，其相关性在花期、花铃期、盛铃期达到极显著水平（P<0.01），其相关系数在盛铃期达到0.924 9的最高值；地膜降解率与土壤含水量亦呈线性负相关关系，其相关性在各生育期均达显著水平（P<0.05），其相关系数的大小顺序是: 花铃期（0.980 2）＞盛铃期（0.978 9）＞花期（0.771 2）＞苗期（0.703 4）＞蕾期（0.695 6）。说明，地膜不同降解率对棉花产量影响显著，地膜降解率与棉田土壤温度、土壤含水量呈线性负相关关系，且地膜降解率高低对盛铃期地温影响最大，对花铃期土壤保墒作用调控最强。为实现环境和产量的双赢目标，在生产中选择适宜降解率的降解地膜十分必要。
To study the effects of the degradable plastic film on preservation of temperature and moisture under the condition of drip irrigation in cotton fields,the field trials were conducted with four coating films of DM1(ordinary polyethylene plastic film),DM2(slow degradable film),DM3(moderate degradable film),and DM4(fast degradable film),and the degradation rate of film,ground temperature,soil moisture,and cotton yield were measured to analyze their relationship. The results showed that,a negative linear relationship was detected between cotton yield and the polyethylene degradation rate during the cotton growth period; film degradation rate was negatively correlated with soil temperature,especially at flower and boll stage and boll period(P<0.01),the correlation coefficient in full bolling period reached the highest value of 0.924 9; film degradation rate and the soil moisture content had a linear relationship,and the correlation at each growth stage was significance(P<0.05) in the order of r value,0.980 2 at flowering and bolling stage>0.978 9 at full bolling period>0.771 2 at flowering stage>0.703 4 at seedling stage > 0.695 6 at budding stage. These results suggested that the film with different degradation rate affected cotton yield significantly; film degradation rate in cotton fields was negative correlated to soil temperature and soil moisture and the significant effect of different degradable films was detected in full bolling period for soil temperature and in flowering and bolling period for soil moisture. Considering environment protection and cotton production,it is necessary to choose appropriate degradable film in agriculture practice.