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P. Chopra ¹, N. N. Angiras ¹, S. Kumar ¹, K. P. Singh ¹

Affiliations
1 Department of Agronomy Forages and Grassland Management, Department of Biology and Environmental Sciences, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur (H.P.) - 176 062, IN

Abstract

A field study was conducted on silty clay loam soils to study the effect of tillage and weed control methods on phenology of maize and associated weeds and their influence on the production of crop. The results revealed that irrespective of tillage and weed control methods, Digitaria sanguinalis, Echinochloa colona and Panicum dichotomiflorum and sedge (Cyperus iria) emerged earlier by 4-8 days than maize crop resulting more competition in the initial stages of growth. Commelina benghalensis emerged and senescenced almost along with the crop. While all other weeds flowered at tasseling stage of the maize crop, Echinochloa colona and Panicum dichotomiflorum flowered 7-8 days earlier to this stage. Senescence of almost all the weeds except Commelina benghalensis occurred 15-25 days earlier than the maize crop. Zero tillage resulted in significantly early emergence of the crop by 4-5 days over other tillage methods but the emergence of grass weeds was not affected significantly. Appearance of all the phenophases of the crop and associated weeds was initiated early in zero till plots as compared to raised seed bed and conventional tilled plots resulting in reduction in grain yield of maize by 13.7 and 16.9 per cent over raised seed bed and conventional tillage. Effective control of weeds with atrazine 1.5 kg/ha and acetachlor 1.25 kg/ha delayed the emergence and appearance of different phenophases of weeds than the crop resulting in 75.2 and 71.7 percent average increase in grain yield of maize, respectively over unweeded check.

Keywords

Acetachlor, Atrazine, Emergence, Raised Seedbed, Senescence, Zero Tillage, Phenology.

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Suresh Kumar ¹, S. S. Rana ¹, Navell Chander ¹, N. N. Angiras ¹

Affiliations
1 Department of Agronomy, Forages and Grassland Management, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur-176 062, IN

Abstract

Two formulations of isoproturon viz. arelon and isoking (1.0 and 1.25 kg a.i./ha) each with 2,4D (0.75 and 1.0 kg/ha) as tankmix and sequence application along with farmers' practice and untreated check were evaluated for weed control in wheat during 200607 and 200708 at Palampur. Phalaris minor (42.6%), Avena ludoviciana(25.1%), Lolium temulentum (11.1%), Vicia sativa, (7.6%), Anagallis arvensis (9.6%), and Coronopus didymus (4.0%) were the major weed species and reduced wheat grain yield by 38.7%. Tankmix application of isoking + 2,4D effectively controlled P. minor, A. ludoviciana and L. temulentum and were on par with farmer's practice. Arelon 1.0 kg a.i./ha + 2,4D 1.0 kg/ha resulted in lowest count of Vicia sativa, while isoking 1.0 kg a.i./ha + 2,4D 1.0 kg/ha resulted in lowest count of Anagallis arvensis. All herbicidal treatments were significantly superior to farmers' practice in controlling C. didymus. Isoking 1.0 kg a.i./ha + 2,4D 1.0 kg/ha recorded highest weed control efficiency (71.5), treatment efficiency index (1.93), crop resistance index (5.0) and resulted in highest grain yield, net returns (Rs. 14373/ha) and marginal benefit:cost ratio (13.2). Isoking 1.25 kg a.i./ha + 2,4D 0.75 kg/ha had highest weed management index, agronomic management index and integrated weed management index.

Keywords

Arelon, Isoking, Isoproturon, Phalaris minor, Avena, Wheat.

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Suresh Kumar ¹, S. S. Rana ¹, N. N. Angiras ¹, Pankaj Chopra ¹, Navell Chander ¹

Affiliations
1 Department of Agronomy, Forages and Grassland Management, CSK Himachal Pradesh Krishi Vishvavidyalya, Palampur-176 062, IN

Abstract

2, 4D 0.5 kg/ha, metsulfuronmethyl 3 g/ha and carfentrazone 10 g/ha each immediately after and 2, 4 and 6 days after clodinafop 60 g/ha were compared to clodinafop alone and untreated check for control of weeds in wheat. Phalaris minor, Avena ludoviciana, Poa annua, Vicia sativa, Anagallis arvensis, Ranunculus arvensis and Coronopus didymus were the important weeds associated with wheat crop. All herbicidal treatments were significantly superior to untreated check in reducing P. minor, Poa annua and A. ludoviciana. Except 2, 4D and carfentrazone immediately after clodinafop, all herbicides completely killed Phalaris minor. 2,4D four days after and metsulfuron immediately after clodinafop gave significantly lower count of V. sativa during 200506 and 200607, respectively. All treatments except clodinafop alone were superior to weedy check in suppressing A. arvensis and R. arvensis. All treatments controlled C. didymus effectively. Application of 2, 4D four days after clodinafop gave maximum yield. However, all other treatments except 2, 4D two days after metsulfuron six days after and carfentrazone four days after clodinafop during 2005 were at par with 2,4D four days after clodinafop. Weeds reduced wheat grain yield by 38.8%.

Keywords

2, 4-D, Clodinafop, Metsulfuron, Carfentrazone, Sequential Application, Phalaris.

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