Dissipation of chlorpyrifos in pakchoi-vegetated soil in a greenhouse.
The dissipation of chlorpyrifos in pakchoi-vegetated soil was investigated in the summer and autumn in a greenhouse and field, respectively. The dissipation of chlorpyrifos in pakchoi-grown soil was comparatively described by fitting the residue data to seven models (1st-order, 1.5th-order, 2nd-order, RF 1st-order, RF 1.5th-order, RF 2nd-order, and bi-exponential or two-compartment models). Statistical analysis was performed using the SPSS 11.5 statistical package. The bi-exponential model was selected as the optimal model according to the coefficient of determination r2. The dissipation half-lives (DT50) of chlorpyrifos in pakchoi-vegetated soil at the recommended dose in the summer and autumn, calculated by the bi-exponential model, were 0.6 and 1.2 d in a greenhouse, 0.4 and 1.0 d in a field, respectively; the corresponding values at double dose were 1.2 and 2.1 d in a greenhouse, 0.5 and 1.3 d in a field, respectively. The kinetic data indicate the dissipation of chlorpyrifos in pakchoi-grown soil in a greenhouse is slower than that in a field, and dissipates slower in the autumn than in the summer.
Fang
Hua
H
Department of Plant Protection, Zhejiang University, Hangzhou, China.
Yu
Yun-long
YL
Wang
Xiao
X
Shan
Min
M
Wu
Xiao-mao
XM
Yu
Jing-quan
JQ
D000383:Agriculture; D001937:Brassica / Q000378:metabolism*; D002681:China; D004390:Chlorpyrifos / Q000032:analysis / Q000737:chemistry*; D004780:Environment, Controlled; D007306:Insecticides / Q000032:analysis / Q000737:chemistry*; D010573:Pesticide Residues / Q000032:analysis / Q000737:chemistry*; D012621:Seasons; D012987:Soil / Q000032:analysis*; D013997:Time Factors
D007306:Insecticides; D010573:Pesticide Residues; D012987:Soil; D004390:Chlorpyrifos