55 Indian Journal of Agricultural Sciences 90 (5): 895–9, May 2020/Article https://doi.org/10.56093/ijas.v90i5.104354 Effcacy of different herbicides on weed dynamics and productivity of kharif maize (Zea mays) and their residual effect on succeeding wheat crop (Triticum aestivum) AJAY SINGH*, MEHAR CHAND, S S PUNIA, NARENDER SINGH and SANDEEP S RANA CCS Haryana Agricultural University, Hisar, Haryana 125 004, India Received: 11 January 2019, Accepted: 31 August 2019 ABSTRACT Weeds are the major biotic constraints in maize crop due to its wider row spacing limiting its productivity. So, a feld experiment was conducted during kharif and rabi seasons of 2015 and 2016, at RRS, Karnal, Haryana to study the effect of different weed control methods on weed fora, growth and yield of kharif planted maize, the residual effect of different herbicides applied in maize on succeeding wheat crop. Treatments included two pre-emergence (PRE) herbicides namely atrazine 750 or 1000 g/ha and alachlor 2000 g/ha along with three post-emergence herbicides (POST) atrazine 500 g/ha, 2,4-D 500 g/ha and tembotrione 120 or 140 g/ha +S (surfactant) at 35 days after sowing (DAS) were used. Hand weeding twice at 20 and 35 DAS, weedy check and weed free treatments were also included. Major weed species infesting the experimental feld were Cyperus rotundus, Brachiaria reptans, Dactyloctenium aegyptium, Amaranthus viridis, Digera arvensis, Phyllanthus niruri and Portulaca oleracea. Among herbicide treatments at 50 DAS, alachlor 2000 g/ha as PRE fb tembotrione 120 g/ha provided the highest weed control effciency (95.1 %). Maximum grain yield (6505 and 6903 kg/ha) and yield attributes of maize were obtained in weed free treatment which was statistically at par with alachlor 2000 g/ha fb tembotrione 120 g/ha +S at 35 DAS (T 13 ) (6380 and 6816 kg/ha). No visual phyto-toxicity of any applied herbicide was observed on maize crop. All herbicide treatments employed in kharif maize, irrespective of their dose and application time did not show any residual carryover effect on succeeding wheat crop. Key words: 2,4-D, atrazine, Alachlor, Tembotrione, Visual phytotoxicity, Weed control effciency In India, maize (Zea mays L.) is the third most important cereal crop after rice and wheat, grown on 9.63 mha area with average yield of 2.69 t/ha and accounts for nearly 9 per cent of total food grain production. Maize-wheat is the third most important cropping system after rice-wheat and rice-rice that contributes about 3% in the national food basket (Anonymous 2016). The present yield levels of maize in India are less than 50% of the world average. Low productivity of maize in India can be attributed to several limiting factors, but the poor weed management poses a major threat to crop productivity. Reduction of 27-60% in maize yield have been reported in various agro-ecologies in India (Kumar et al. 2012). Thus, proper weed management strategies would continue to play an important role in increasing its production and requires redesigning of weed control strategies from time to time. Maize, being a widely spaced crop, gets infested by a wide range of weed fora (Punia et al. 2007). Manual weeding in maize is costly and labour-intensive method. Moreover, due to inclement weather conditions, it is not possible to go for manual hoeing. Most of the presently available herbicides provide only narrow spectrum of weed control in maize. So, there is a need to test new herbicides alone or in combination, which are effective against complex weed fora in kharif maize. The knowledge on the persistence and residual effect of herbicides in soil is essential to use them safely, effectively and for non-hazardous chemical weed control schedules. So, it becomes imperative to work out safe combination and time of application of herbicides in maize without affecting the growth and yield of succeeding wheat crop. Therefore, the present investigation was undertaken to evaluate different herbicide combinations for controlling complex weed fora in kharif maize and their residual effect on succeeding wheat crop. MATERIALS AND METHODS A feld experiment was conducted during kharif and rabi seasons of 2015 and 2016 with maize-wheat cropping sequence on same fxed plots at Regional Research Station, Uchani, Karnal of CCS Haryana Agricultural University, Hisar, Haryana (India). Karnal is situated at 245 m above mean sea level with longitude of 67º58'' North and latitude 29º43'' East in sub-tropical zone. Total 426- and 597-mm *Corresponding author email: ajayyadavhau@gmail.com