典型黄壤烟田莠去津残留降解及烟草致害阈值研究

Study on the Residual Degradation of Atrazine and Damage Threshold of Tobacco in Typical Yellow Soil Tobacco Fields

通过田间试验研究贵州典型黄壤烟田莠去津的残留和消解动态,阐明烟草的药害发生及烟草的致害阈值与安全间隔期,并分析土壤环境因素对莠去津半衰期的影响。结果表明:莠去津对烟草生长发育的抑制作用十分明显,显示为叶片瘦小、严重者畸形,老叶叶尖脉黄化。烟草株高抑制率、叶面积抑制率与莠去津施药剂量均呈极显著正相关,随莠去津施用剂量的增加,株高和叶面积的抑制率增加。莠去津在典型黄壤中降解半衰期为8.45~11.95 d,田间安全隔离期应长于48.6 d,莠去津降解半衰期与土壤有机质含量呈显著正相关,与pH和速效钾呈显著负相关,与碱解氮和有效磷含量相关性不显著。研究结果对黄壤高粱/玉米-烟草轮作系统除草剂合理施用及烟叶安全性具有重要指导价值。

Field experiments were conducted to study the residue and degradation dynamics of atrazine in typical yellow soil tobacco fields in Guizhou Province,the occurrence of tobacco pesticide damage and the threshold and safety interval of tobacco damage was elucidated.The effects of soil environmental factors on the half-life of atrazine was analyzed.The results showed that atrazine inhibited the growth of tobacco significantly,which showed that the leaves were small,serious deformity,the old leaf tip vein began to yellow.The inhibition rates of plant height and leaf area were significantly positively correlated with atrazine dosage.The inhibition rates of plant height and leaf area increased with the increase of atrazine dosage.The degradation half-life of atrazine in typical yellow soil was 8.45-11.95 d,and the safe isolation period in the field should be longer than 48.6 d.The degradation half-life of atrazine was significantly positively correlated with the content of soil organic matter,there was significant negative correlation with pH and available potassium,but no significant correlation with available phosphorus and available nitrogen.The results had great significance to the scientific application of herbicides and tobacco safety in the sorghum/maize-tobacco rotation area of yellow soil.