Abstract

                                A Field experiment was carried during rabi, 2016-17 at the Department of Agronomy, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai to find out the residual effect of slow release herbicide formulations on weed and bhendi in the rice-bhendi crop sequence. Among weed control treatments, the residual effect of butachlor at 1.25 kg/ha on 3 DAT fb HW on 40 DAT recorded significantly lower total weed density of 21.33/m2 and 51.17/m2 at 20 and 40 DAS respectively. It was on par with the residual effect of oxadiargyl loaded in zeolite applied at 3 DAT, whereas, at 60 DAS and at harvest stage, the residual effect of oxadiargyl encapsulated with water-soluble polymer and loaded in zeolite applied on 3 DAT recorded lower weed density. Significantly, lower weed dry weight was recorded in butachlor at 1.25 kg/ha on 3 DAT fb HW on 40 DAT + HW twice at 20 and 40 DAS which was on par with residual effect of oxadiargyl loaded in zeolite at 3 DAT and oxadiargyl loaded in biochar at 3 DAT compared to all other treatments at 20 DAS. The same pattern was observed in total weed dry weight at 40, 60 DAS and at harvest stage except oxadiargyl loaded in biochar at 3 DAT. Slow release formulation of oxadiargyl recorded higher germination percentage of bhendi as compared to commercial formulations and weedy check. Weed-free check, butachlor at 1.25 kg/ha fb HW on 40 DAT, oxadiargyl loaded in zeolite applied to previous rice crop on 3 DAT has recorded higher bhendi fruit yield of 6.40, 3.70, 1.53 times against weedy check.

Key words : Encapsulated, Loaded, Oxadiargyl, Weed, Fruit yield, Bhendi