禾草灵对水稻生长和典型土壤酶活性的影响

禾草灵是一种广泛使用的除草剂,在土壤中大量残留,对非靶标生物产生危害。为探究除草剂对环境生物的毒性作用,本研究模拟水稻自然生长的环境,评估禾草灵对水稻及土壤微生物的影响。研究结果表明,低浓度禾草灵(200μg·L-1)处理4d对土壤微生物量没有显著影响(P0.05);8 d时,水稻生长没有明显变化,但土壤微生物量较对照组显著升高(P0.05)。高浓度禾草灵(1 000μg·L-1)处理4 d后,土壤脲酶、酸性磷酸酶和过氧化氢酶的活性显著下降(P0.05),下降幅度分别为8.9%,16.6%和10.2%;处理8 d后,水稻幼苗鲜重显著降低(P0.05),叶绿素a和叶绿素b含量分别下降了13.5%和13.3%。本研究证实高浓度的禾草灵残留会对植物和土壤微生物产生不良的影响。

The Effects of Diclofop-Methyl on Rice Growth and Typical Soil Enzyme Activities

Diclofop-methyl,a post emergence herbicide is being used to control weeds (annual grasses and wild oats) in major as well minor crops worldwide.Its subsequent capability of permeation inundate it into surrounding soil and water,exert potential threat on non-target plants and soil microorganisms.We established the rice growth in natural environment to evaluate the effects of diclofop-methyl on rice seedlings and soil microorganisms.The results revealed that low concentration of diclofop-methyl (200 μg· L-1) caused zero effect on soil microbial biomass after 4 d of exposure (P＞0.05),but soil microbial biomass was significantly stimulated after 8 d of exposure (P＜0.05).In the groups treated by high concentration of diclofop-methyl (1 000 μg·L-1),however,the enzyme activities of soil urease,acid phosphatase and catalase decreased by 8.9％,16.6％ and 10.2％ of the control after 4 d of exposure,respectively (P＜0.05),while after 8 d of exposure,the fresh weight was reduced dramatically,and the content of chla and chlb dereased by 13.5％ and 13.3％,respectively (P＜0.05).This research verdict that high concentration of diclofop-methyl could affect rice growth and soil microorganism metabolic function.