Effect of the herbicides oxadiazon and oxyfluorfen on phosphates solubilizing microorganisms and their persistence in rice fields.
A field experiment has been conducted with two herbicides viz. oxadiazon [5-terbutyl-3-(2,4-dichloro-5-isopropoxyphenyl)-1,3,4-oxadiazol-2-one] and oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenyl)-4-(trifluoromethyl) benzene] at rates of 0.4 and 0.12 kg a.i. ha(-1), respectively, to investigate their effect on the growth and activities of phosphate solubilizing microorganisms in relation to availability of phosphorus as well as persistence of the herbicides in the rhizosphere soil of wetland rice (Oryza sativa L. variety IR-36). Application of herbicides stimulated the population and activities of phosphate solubilizing microorganisms and also the availability of phosphorus in the rhizosphere soil. Oxyfluorfen provided greater microbial stimulation than oxadiazon. Dissipation of oxyfluorfen and oxadiazon followed first order reaction kinetics with half-life (T(1/2)) of 8.8 and 12 days, respectively. Sixty days after application 0.5% and 3% of the applied oxadiazon and oxyfluorfen residues persisted, respectively, in the rhizosphere soil of rice.
Das
Amal Chandra
AC
Department of Agricultural Chemistry and Soil Science, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur 741 252, India. acdas2@rediffmail.com
Debnath
Anjan
A
Mukherjee
Debatosh
D
D001419:Bacteria / Q000187:drug effects*; D001682:Biological Availability; D004777:Environment; D055768:Halogenated Diphenyl Ethers; D006540:Herbicides / Q000737:chemistry / Q000494:pharmacology*; D012275:Oryza; D010069:Oxadiazoles / Q000737:chemistry / Q000494:pharmacology*; D010647:Phenyl Ethers / Q000737:chemistry / Q000494:pharmacology*; D010758:Phosphorus / Q000493:pharmacokinetics; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology
D055768:Halogenated Diphenyl Ethers; D006540:Herbicides; D010069:Oxadiazoles; D010647:Phenyl Ethers; D012987:Soil; D010758:Phosphorus; C016027:oxyfluorofen; C012466:oxadiazon