咪唑烟酸在不同土壤中的降解动态及其影响因子

Studies on Degradation Dynamics of Imazapyr and its Influencing Factors in Different Kinds of Soil

研究了咪唑烟酸在小粉土、海涂土、黄筋泥及黄红壤4种不同类型土壤中的降解动力学,并探讨了土壤各性质对其降解的影响。结果表明:咪唑烟酸在4种土壤中的降解速率常数分别为0.0227、0.0233、0.0175、0.0157,即在海涂土中降解最快,在黄红壤中降解最慢。土壤中影响降解的主要因子为有机质含量,其次为土壤酸碱度,即有机质含量越高,土壤碱性越强,则其半衰期越短,降解速度越快。外界环境条件对咪唑烟酸的降解影响也较大,温度越高,湿度越大,则咪唑烟酸的降解越快,温度效应系数(Q)的范围在1.08～1.42之间,与范特荷夫(Van,tHoff)规则不吻合,说明温度对咪唑烟酸在土壤中降解速率的影响明显低于对水解的影响,最适的降解温度为25～35℃。与上述因子的影响相反,添加浓度高,则降解速率明显下降。

The degradation dynamics of imazapyr in four kinds of soil i.e. powder soil, coast soil, yellow red loam soil and huangjin mud were studied respectively, and the effect of soil-property on degradation was also investigated. The degradation rate constant were 0.022 7,0.023 3,(0.017 5) and 0.015 7 respectively in four kinds of soil, among which the fastest occurred in coast soil and the slowest in yellow red soil. The important factors, which influence degradation rate of imazapyr in soil, are organic matter content (OMC) and pH values. Environmental factors also affect imazapyr-degradation rate which will increase as temperature and moisture rise. (Temperature) effect coefficient(Q) varies from 1.08 to 1.42, which is not in accordance with (Van't) Hoff law, and it is proved that the effect of temperature on degradation rate in soil is less than on the (decomposition ) in water. On the contrary, the degradation rate will decrease when the (fortified) concentration goes up.