苄嘧磺隆·苯噻酰草胺0.42％颗粒剂在稻田中的残留及消解动态

为明确苄嘧磺隆和苯噻酰草胺在稻田系统中的使用安全性,于2010、2011年在杭州、长沙和南宁进行田间试验,研究苄嘧磺隆·苯噻酰草胺0.42％颗粒剂在水稻中的消解动态和最终残留.结果表明,在稻田土壤、水、糙米、谷壳和水稻植株中添加的苄嘧磺隆和苯噻酰草胺的平均回收率为70.78％～ 116.06％,相对标准偏差(RSD)为0.91％～10.24％;苄嘧磺隆和苯噻酰草胺的检出限(LOD)均为0.02 mg/L,最小检出量均为4.0×10-9 g.在水稻移栽后5～7 d,采用直接撒施法在高剂量(270 kg/hm2,其中苄嘧磺隆有效成分为64.8 g/hm2,苯噻酰草胺有效成分为1 069.2 g/hm2)下施药1次的消解动态试验结果表明:苄嘧磺隆和苯噻酰草胺在稻田水、稻田土壤和水稻植株中的消解动态曲线均符合一级动力学方程,苄嘧磺隆在稻田水、稻田土壤和水稻植株中的平均消解半衰期分别为5.35,3.05和3.71 d,苯噻酰草胺在稻田水、稻田土壤和水稻植株中的平均消解半衰期分别为3.61,3.29和3.88 d.分别按低剂量(180 kg/hm2,其中苄嘧磺隆有效成分为43.2 g/hm2,苯噻酰草胺有效成分为712.8 g/hm2)和高剂量(270 kg/hm2)施药1次,在正常收获期采集的稻田土壤、稻杆、谷壳和糙米中均未检测出苄嘧磺隆和苯噻酰草胺.

Residue and Degradation Dynamics of Bensulfuron-methyl· Mefenacet 4.2 g/kg Granule in Paddy Field

This study was conducted to determine the safety of bensulfuron-methyl and mefenacet in rice ecosystem.A field experiment was carried to reveal residual dynamics and final residue of bensulfuron-methyl·mefenacet 4.2 g/kg granule in rice and paddy system in Hangzhou,Changsha and Nanning of China during 2010 to 2011.The results showed that the average recoveries of bensulfuron-methyl and mefenacet spiked in the paddy soil,paddy water,rice,husk and rice plant at the 3 concentration levels of 0.05,0.10 and 1.00 mg/kg ranged from 70.78％ to 116.06％ with the relative standard deviations of 0.91％-10.24％.The limit of detection (LOD)values of bensulfuron-methyl and mefenacet were 0.02 mg/L,and the minimum detection quantities were 4.0×109 g.The degradation dynamics test was done by spraying at a high dose (270 kg/hm2,bensulfuron-methyl active ingredient was 64.8 g/hm2,mefenacet active ingredient was 1 069.2 g/hm2) by direct spreading method 5-7 d after transplanting,and the final residual test carried out at a low dose (180kg/hm2,bensulfuron-methyl active ingredient was 43.2 g/hm2,mefenacet active ingredient was 712.8 g/hm2) and a high dose (270 kg/hm2).The degradation research of bensulfuron-methyl and mefenacet in paddy water,soil and rice plant suggested that the degradation curves accorded with the first-order kinetics equation,the average half life of bensulfuron-methyl was 5.35,3.05 and 3.71 d in water,soil and rice plant,respectively,and the average half life of mefenacet was 3.61,3.29 and 3.88 d in water,soil and rice plant,respectively.The final residues of bensulfuron-methyl and mefenacet were not detected in normal harvest paddy soil,rice straw,husk and brown rice.