Vol. 18 No. 3
Evaluation of glyphosate ammonium 79.2% SG for weed dry weight, crop phytotoxicity, yield, available NPK and economics of tea (Camellia sinensis L.)
Author(s): S. TANHA, P. CHOPRA, S. S. RANA, G. SINGH AND N. KAUR
A field experiment to evaluate the phytotoxicity of glyphosate ammonium 79.2% SG in tea crop was conducted during the summer and monsoon seasons of 2018 at Palampur. Eight different weed control treatments were tested against weedy check and weed free in randomized block design with three replications. Glyphosate ammonium 79.2% SG at 4.356 kg ai ha-1 was slightly phytotoxic upto one month of its application. Glyphosate ammonium 79.2% SG at 2.178 kg ai ha-1 and tank mix application of glyphosate 1.0 L ha-1 along with 2,4-D (Na) 0.5 kg ha-1 had significantly higher made tea yield. The presence of weeds in weedy check resulted in a loss of 47.5% in made tea yield. Glyphosate at 1.0 L ha-1 along with 2,4-D (Na) at 0.5 kg ha-1 and glyphosate ammonium salt 79.2% at 4.356 kg ai ha-1 resulted in significantly greater available N. Significantly higher K in soil was recorded with glyphosate ammonium 79.2% at 4.356 & 2.178 kg ai ha-1, glyphosate+2,4-D (Na) 1.0L+0.5 kg ha-1, glyphosate ammonium 71.0% at 2.13 kg ai ha-1 and weed free check. Combined application of glyphosate at 1.0 L ha-1 with 2,4-D (Na) at 0.5 kg ha-1 and glyphosate ammonium 79.2% at 2.178 kg ai ha-1 had higher value of net returns of INR 2,71,487 ha-1 and INR 2,68,024 ha-1, respectively. Both of these treatments also had highest value of net returns per rupee invested (2.27).