施药与采样技术对代森锰锌在苹果和土壤中残留量的影响

Effects of application and sampling techniques on initial residues of mancozeb on apple and in soil

研究了施药技术和采样方法对土壤和苹果中代森锰锌残留原始沉积量的影响.结果表明,在不同剂型、相同有效成分用药量下,代森锰锌在土壤中的原始沉积量不同,30%代森锰锌悬浮剂喷雾后在土壤中的原始沉积量(1.37—1.57 mg·kg-1)高于70%可湿性粉剂(1.03—1.26 mg·kg-1)和75%水分散粒剂(1.04—1.17 mg·kg-1);同种剂型和剂量条件下,施药液量对代森锰锌在土壤中的原始沉积量有显著影响,随着施药液量的增加,原始沉积量呈递减趋势.喷片孔径从0.7 mm增大至1.6 mm时,代森锰锌在土壤中的原始沉积量由0.76 mg·kg-1增大至0.90 mg·kg-1.样品直径6 cm和8 cm对苹果上原始沉积量影响不大.相同施药量下不同苹果品种残留量差异显著.重复间小直径样品所占比例升高,残留量增大.可见施药技术和采样方法是影响农药原始沉积量的主要因素.

Effects of application and sampling techniques on initial residues of mancozeb on apple and in soil was studied. The results showed that,the initial residues on apple and in soil of different formulations of mancozeb with same application rate were differentiated. The initial residues in soil by spraying of mancozeb 300 suspension concentrate（1.37 —1.57 mg·kg-1） was higher than that of other 2 formulations,namely mancozeb 700 wettable powder（1.03—1.26 mg·kg-1） and mancozeb 750 water dispersible granule（1.04—1.17 mg·kg-1）. Under the same formulation and same application rate,the sprayed volume was decisive. The initial residues of mancozeb tended decreasing with increasing of sprayed volume. When the nozzle diameter changed from 0.7 to 1.6 mm,the initial residues of mancozeb in soil increased from 0.76 to 0.90 mg·kg-1. Change of apple diameters from 6 to 8 cm had no significant effects on initial residues. There was significant difference between varieties of apple. The initial residues of mancozeb increased with increase fraction of small apples in the same testing plot. This implied that application techniques and sampling methods are the main factors leading to initial residue change.