~ 535 ~ International Journal of Chemical Studies 2017; 5(3): 535-539 P-ISSN: 2349–8528 E-ISSN: 2321–4902 IJCS 2017; 5(3): 535-539 © 2017 JEZS Received: 23-03-2017 Accepted: 24-04-2017 R Sathya Priya Research Associate, Directorate of Crop Management, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India C Chinnusamy Professor of Agronomy & PI (AICRP Weed Management), Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India P Murali Arthanari Assistant Professor, Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India P Janaki Assistant Professor, Soil Science & Agricultural Chemistry, Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India Correspondence R Sathya Priya Research Associate, Directorate of Crop Management, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India Carryover effect and plant injury from oxyfluorfen herbicide applied in transplanted rice R Sathya Priya, C Chinnusamy, P Murali Arthanari and P Janaki Abstract A field investigation were carried out at the Agricultural Research Station, Bhavanisagar of Tamil Nadu Agricultural University, Coimbatore, India during rabi season of 2010 and 2011 to evaluate the new formulation of oxyfluorfen (23.5% EC) on weed control in transplanted rice and their residual effect on succeeding crops. Oxyfluorfen is a diphenyl-ether herbicide as a pre or post-emergence herbicide used for control of annual and perennial broad-leaved weeds in a variety of field crops. Many of the field experiments revealed that the bio-efficacy of oxyfluorfen herbicide; however, no information is available on the field persistence of oxyfluorfen, phytotoxicity symptoms in plant and carryover effect in succeeding crops under Indian tropical conditions. Therefore, the field experiments were undertaken to investigate the plant injury and persistence of oxyfluorfen in soil and rice crop in red sandy clay loam soil. Bioassay remains a major tool for qualitative and quantitative determination of herbicides residue in soil. Detection of the oxyfluorfen herbicide in soil can be done by bioassay which measures the biological response of a living plant to that particular herbicide. Based on two years field experimentation, the results clearly indicated, Pre-emergence (PE) application of oxyfluorfen (23.5% EC) at 250 g a.i. ha -1 can keep the weed density and dry weight below the economic threshold level and increased the rice grain yield. Plant injury symptoms of oxyfluorfen was complete recovery of affected rice plants could be observed only after 30 days after herbicide application (DAHA) and the phytotoxicity was not evident thereafter in rice crop. Carryover effect results showed that the oxyfluorfen herbicide to be safe on the succeeding crops and this might be due to detoxification of herbicides in soil and do not adversely affect the growth attributes of the succeeding crops in terms of germination percentage and dry matter production of the succeeding sunflower and blackgram. Keywords: Rice, oxyfluorfen, grain yield, plant injury, carryover effect, succeeding crop safet Introduction To meet the global rice demand, it is estimated that about 114 million tonnes of additional milled rice need to be produced by 2035 which is equivalent to an overall increase of 26% in the next 25 years (Kumar and Ladha, 2011) [5] . There is a need to sustain the present food self- sufficiency and to meet future food requirements. India has to increase its rice productivity by 3% per annum but the possibility of expanding the area under rice in the near future is limited. Weeds constitute one of the biggest problems in agriculture that also reduce the yield and also utilize essential nutrients. Most of the improved crop management practices in rice cultivation failed due to poor and improper practices for containing weeds. Weeds compete with rice for moisture, nutrients, light, temperature and space. Pillai and Rao (1974) [9] estimated the extent of yield reduction due to weeds to be over 50% in direct seeded upland rice, 30-35% in direct seeded rice under puddled condition and around 15-20% in transplanted rice. Uncontrolled weeds have caused yield reduction of 28-45% in transplanted rice (Singh and Singh, 2007; Manhas et al., 2012) [14, 6] . Furthermore, any delay in weeding will lead to increased weed biomass which has a negative correlation with yield. Hand weeding is the traditional weed control measure in rice cultivation practices. However, due to high labour cost, non- availability of labour and time taken for manual removal, farmers are forced to decide for cheaper alternative of chemical weed control. Most of the presently available herbicides provide only a narrow spectrum weed control. Many of them have activity only on annual species, while a few are only effective against perennial weeds. Plenty of the new formulation of herbicides is recommended for each crop and in a cropping system, sequential application of herbicides for every crop leads to residue accumulation in soil and crop, thus causing adverse effect of succeeding crops.