土壤聚乙烯含量对油菜发芽出苗及幼苗的影响

Influence of Soil Polyethylene Content on Rape's Emergence and Seedling Growth

为探索土壤中农用地膜降解产物对油菜种子发芽出苗及幼苗生长的影响,用线性低密度聚乙烯(LLDPE)模拟可降解地膜粉末,以5 000分子量聚乙烯模拟可降解地膜分解后的低分子化合物,聚乙烯在土壤(干土,下同)中含量为0、1、10、100、500 g/kg,研究甘蓝型油菜和芥菜型油菜种子播后7、13 d的发芽出苗率及播后13 d芽长和根长。结果表明,不同油菜品种、不同聚乙烯、不同聚乙烯含量对油菜播后13 d出苗的影响显著或极显著。土壤LLDPE含量在1～100 g/kg,对甘蓝型油菜13 d出苗率比对照提高4.40%～8.40%;土壤LLDPE含量在100～500 g/kg时,对芥菜型油菜13 d出苗率比对照提高19.69%～36.09%。不同油菜品种、不同聚乙烯、不同聚乙烯含量对油菜播后13 d的幼芽长度影响显著或极显著,聚乙烯不同含量对油菜根长影响极显著。LLDPE含量为10～100 g/kg时,促进两种油菜幼芽生长,抑制甘蓝型油菜根系生长。可降解地膜粉末和分解的低分子化合物对不同油菜品种的发芽出苗和幼苗生长有不同的影响。对油菜生产面积占绝对优势的甘蓝型油菜而言,LLDPE在土壤中含量1～100g/kg时,会促进播后13 d的出苗,促进幼芽生长或影响不大,抑制根系生长。5 000分子量聚乙烯在土壤含量1～10g/kg时,对甘蓝型油菜播后13 d的出苗和根系生长略有抑制作用,但促进幼芽生长。

The influence of degradation products of agricultural film in soil on the emergence of rape seeds and seedling growth was studied.Degradable mulching film powder was simulated with linear low density polyethylene（LLDPE） and decomposed low molecular compounds was simulated with 5 000 molecular weight polyethylene.Polyethylene application content in soil was 0,1,10,100,and 500 g/kg dry soil.The emergence percentage of Brassica napus L.and Brassica juncea L.on the 7th day and the 13th day after sowing were counted,and bud length and root length of the seedling on the 13th day after sowing were measured.The results showed that different rape varieties,different types and different contents of polyethylene had significant or very significant influences on the emergence percentage of the rape on the 13th day after sowing.The emergence percentage of B.napus was 4.40%~8.40% more than CK when LLDPE content was 1～100 g/kg.The emergence percentage of B.juncea was 19.69%~36.09% more than CK when LLDPE content was 100～500 g/kg.Also different rape varieties,different types and different contents of polyethylene had significant or very significant influences on shoot length on the 13th day after sowing.Different contents of polyethylene influenced the length of rape root significantly.The shoot length of two rape rarieties increased and the root length of B.napus was inhibited when LLDPE was 1～100 g/kg dry soil.Degradable mulching film powder and decomposed low molecular compound had different influences on the emergence percentage and seedling growth of different rape varieties.To B.napus,which has an absolutely advantage in production area of rape,LLDPE of 1～100 g/kg dry soil promoted its seed emergence（13 d） and shoot growth,but inhibited root growth.5 000 molecular weight polyethylene of 1～10 g/kg dry soil had a slightly inhibition effect on the seed emergence and root growth of B.napus on the 13th after sowing,but had a promotion effect on shoot growth.