Crop Management Bangladesh Agron. J. 2024, 27(2): 78-89 EFFECT OF INTEGRATED WEED MANAGEMENT PRACTICES ON WEED GROWTH AND YIELD OF SORGHUM IN WINTER S.S. Kakon*, S.S. Nasreen, A.A. Begum, J.A. Chowdhury, M.Z.A. Mantu, S.T. Zannat and M.A.H. Khan Agronomy Division, Bangladesh Agricultural Research Institute, Gazipur 1701, Bangladesh *Corresponding author, Email: kakonbari@gmail.com (Received: 13 June 2025, Accepted: 28 August 2025) Keywords: Sorghum, weed management, weed dry matter, weed control efficiency, yield Abstract The field experiment was conducted at Agronomy Division, Bangladesh Agricultural Research Institute, Gazipur, during Rabi season of 2022-23 and 2023-2024 to study the effect of integration of chemical and cultural methods for weed management in sorghum. There were seven treatment viz. T1 = Two hand weeding at 25 and 40 days after sowing (DAS), T2 = Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (DAS), T3 =Atrazine @ 2 L ha−1 spraying as pre-emergence + weeding by BARI weeder at 25 days after sowing (DAS), T4 = Atrazine @ 2 L ha−1 spraying as post-emergence at 25 DAS + one hand weeding at 40 days after sowing (DAS), T5 = Pendimethalin @ 3 L ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (DAS), T6 = Pendimethalin @ 3 L ha−1 spraying as pre-emergence and T7= No weeding and no herbicide were included in the experiment. Barnyard grass (Echinochola crusgalli), Harkuch (Enhydra fluctuans), Nutsedge (Cyperus rotundus) and Jersey cudweed (Gnaphalium affine) were the common and dominant weeds in the sorghum field. Results showed that the highest weed control efficiency (WCE) (84.4% at 25 days after establishment (DAE) and 90.2% at 45 DAE at 2022-23 and 85.28% at 25 DAE and 81.58% at 45 DAE at 2023-24) was found in T2 treatment. Significantly the highest two years average yield (3.64 kg ha−1) was obtained from T5 treatment. The highest gross return of (Tk. 109300 ha−1) and benefit cost ratio (BCR) (2.01) were also obtained from T5 treatment. From the result it might be concluded that, two herbicides (Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAS and Pendimethalin@ 3 L ha−1spraying as pre-emergence + one hand weeding at 25 DAS) were found economical by recording higher net returns and BCR compared to control. Introduction Sorghum (Sorghum bicolor L.) is considered as king of millets and extensively grown in semi- arid tracks of Africa, China and India. The area under sorghum cultivation was recorded as 6316 acres in 1996-1997 but it continuously decreased and reached to 745 acres in 2017-2018 (BBS, 2018). It has multiple uses as grain, fodder and more recently as bifo energy crop. In Asia and Africa sorghum grain is consumed by human or as animal feed, stalks are used as fodder or housing material. Sorghum has a high nutritive value, with 70-80% carbohydrate, 11-13% protein, 2-5% fat, 1-3% fibre, and 1-2% ash. Protein in sorghum grain is gluten free and thus it is specifically a food for people who suffer from celiac disease (intolerant to food with gluten), including diabetic patients. Comparing the production potential of sorghum, the low productivity in Bangladesh is attributed to several reason. Among them weed is a major constrains. Weeds are major problems in increasing productivity of the crop. It was reported that yield loss of sorghum due to weeds ranges from 15-97%, depending on the nature and density of weeds (Thakur et al. 2016). Weeds germinated fast and grow rapidly at initial growth period of crops competing with the crops 79 Kakon et al. severely for growth resources, viz. nutrients, moisture, sunlight and space. This affects the growth and development of crop and leads to yield losses (Freitas et al., 2014). Weed management in grain sorghum is a challenge because of the limited number of herbicides available to growers, rotational crop restrictions following a number of herbicides registered for use in grain sorghum and presence of herbicide resistant weeds. Traditional hand weeding is the most efficient and widely adopted practice of weed management but it is labor intensive, time consuming and not economical due to high wage rates. Mechanical equipment can be time saving during peak operation, resulting in higher output per worker and reduction in the cost of weeding. Chemical weed control is a better supplement to conventional method however the weed emergence pattern, application timing and stage of crop are important in chemical control. Continuous use of herbicides over a prolonged time leads to development of resistance in weeds making them difficult to control. Integrated weed management (IWM), the process of combining several single management strategies together to suppress weeds has been developed. Hence, various components of integrated weed management are to be blended in a systematic way to achieve the acceptable level of weed control. The integration of herbicides with cultural operations and use of pre-emergence and post-emergence herbicides in combination with mechanical methods will makes the crop weed free effectively and thus, improves the crop growth as well as yield. The integrated weed management is, therefore, gaining importance in management of weeds for preventing yield losses and higher input-use efficiency. Herbicide application in Bangladesh is expected to increase in future due to labor scarce situation. The present investigation was carried out to study the effect of integrated weed management practices on weed density, weed dry weight and economics in sorghum. Materials and Methods Field experiment was conducted at the research farm of Bangladesh Agricultural Research Institute, Gazipur during Rabi season of 2022-2023 and 2023-2024. The experiment site was located Chhiata Series under Agro-Ecological Zone-28 (AEZ-28) latitude 23059’ N and longitude 90024’ E. The meteorological data of the experimental site revealed that the highest temperature prevails in March-April and the lowest in December to January. Maximum rainfall was received during the months of January. The crop received 543 mm rain showers from November to March in 2023-24years. The average maximum (32.08 °C) was found in the month of March during the crop growing season (Fig. 1.) and minimum (12.77 °C) temperature in the month of January during the crop growing season (Fig. 1.). The experiment was consisted of seven treatments viz. T1 = Two hand weeding at 25 and 40 DAS, T2 = Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAS, T3 =Atrazine @ 2 L ha−1 spraying as pre-emergence + weeding by BARI weeder at 25 DAS, T4 = Atrazine @ 2 L ha−1 spraying as post-emergence at 25 DAS + one hand weeding at 40 DAS, T5 = Pendimethalin @ 3 L ha−1spraying as pre-emergence + one hand weeding at 25 DAS, T6 = Pendimethalin @ 3 L ha−1 spraying as pre-emergence and T7= No weeding and no herbicide. The experiment was laid out in randomized complete block design with three replications. The unit plot size was 3m × 3m. Seeds of sorghum (BARI Sorghum-1) were sown on 25 November, and harvested on 1 April, 2023 and 2nd year sown on 28 November 2023 and finally harvested on 5 April 2024. Fertilizers were applied at the rate of 120-60-50 kg ha−1 of NPK as urea, triple superphosphate (TSP), muriate of potash (MOP) for grain sorghum. One third N and all other fertilizers were applied as basal. Rest N was be applied at 20 and 40 DAS. Three times of irrigation were applied in field. Weed sample were collected (1 m2 per each plot) at 25 DAS and 45 DAS and dry matter was taken after oven dry. Weed control efficiency (WCE) was calculated according to following formula: Weed Control Efficiency (WCE%) = ( 𝐴−𝐵 𝐴 ) × 100 Effect of integrated weed management practices on weed growth and yield of sorghum 80 Where, A = Dry weight of weeds in no weeding plots and B = Dry weight of weeds in treated plots. Yield and yield contributing characters were recorded and pooled data analyzed statistically with STATISTICS 10 statistical package. The means were separated by least significant difference test (LSD 0.05%). Fig. 1. Mean temperature and rainfall prevailed during sorghum growing periods at Gazipur Results and Discussion Weed species and their relative density and number of weeds m−2 in different treatments are presented in Table 1.The weeds flora infesting the sorghum field were Harkuch (Enhydra fluctuans), Barnyard grass (Echinochloa crusgalli), Scrab grass (Digitaria sanguinalis), Kanainala (Cyanotis axillaris), Goose grass (Eleusine indica), Nutsedge (Cyperus rotundus), Vetch (Vicia sativa), Bitter dock (Rumexm aritimus), Bermuda grass (Cynodon dactylon), Lambsquarte (Chenopodium album), Alligator weed (Alternanthera philoxeroides), Paspalum grass (Paspalum commersonii), Hatishur (Heliotropium indicum) and pig weed (Amaranthus viridis). Among the weed species, Barnyard grass (Echinochloa crusgalli), Harkuch (Enhydra fluctuans), Nutsedge (Cyperus rotundus), Bermuda grass (Cynodon dactylon) and Jersey cudweed (Gnaphalium affine) were the common and dominant weeds in the sorghum field. The relative density of the major weed species among the treatments ranges from 18.81-74.04, 1.78-23.33,2.96-20,2.12 -6.29 and 16.97 -33.86%, respectively. C. dactylon, E.crusgalli, C. rotundus, G. affine and E. fluctuansat 25 days after emergence (DAE). D. sanguinalis, E. indica, C. rotundus, V. sativa and R. maritimus occured in lesser number at 25 DAE. At 45 DAE, C. dactylon, E. crusgalli, C. rotundus and G. affine were found as major weeds with their relative density among the different treatments ranges from 7.17-45.24, 3.00-13.33, 1.63-24.39 and 2.22-25.09%, respectively. E. fluctua, P. commersoni, A. viridis, H. indicum and C. album occurred in lesser number. Two hand weeding (HW) recorded significantly lower number of all the weed m−2 at 25 and 45 DAE. At 25 DAE, among the weed management plots the number of weeds ranged from 40 to 63 m−2. The highest weed population (106 m−2) was recorded in T7 treatment at 25 DAE. At 45 DAE, numbers of weeds ranged from 45 to 82 m−2. The highest weed population (186 m−2) was recorded in T7 treatment at 45 DAE. The number of weeds were increased in all the plots at 45 DAE than 25 DAE. Among the chemical treatments, application of Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAS, Pendimethalin @ 3 L ha−1 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 40 N o v. 1 N o v. 7 N o v. 1 3 N o v. 1 9 N o v. 2 5 D e c. 1 D e c. 7 D e c. 1 3 D e c. 1 9 D e c. 2 5 D e c. 3 1 J a n .6 J a n .1 2 J a n .1 8 J a n .2 4 J a n .3 0 F e b .5 F e b .1 1 F e b .1 7 F e b .2 3 M a r. 1 M a r. 7 M a r. 1 3 M a r. 1 9 M a r. 2 5 M a r. 3 1 6 -A p r M a x . a n d m in . te m p e ra tu re ( 0 c) Date and month Min Max Raifall R ain fall (m m ) 81 Kakon et al. spraying as pre-emergence + one hand weeding at 25 DAS and Atrazine @ 2 L ha−1 spraying as post-emergence at 15 DAS + one hand weeding at 40 DAS were very effective in controlling the weeds which recorded a weed density of 45 and 49, respectively (Table 1). Table1. Effect of different of weed management method on weed species, weed number m−2 and weed density (%) over time average two years Treatment English name Scientific name 25 DAE 45 DAE Number of weed m−2 Weed density (%) Number of weed m−2 Weed density (%) T1 Scrab grass Digitaria sanguinalis - - 4 4.88 Nutsedge Cyperus rotundus 8 20.00 1 1.63 Alligator weed Alternanthera philoxeroides - - 7 8.13 Harkuch Enhydra fluetuans 8 20.00 Vetch Vicia satiua - 4 4.88 Barnyard grass Echinochloa crusgali 9 23.33 9 11.38 Jersey cudweed Gnaphalium affine - 4 4.88 Bitter dock Rumexm aritimus 3 6.67 3 3.25 Goose grass Eleusine indica 3 6.67 Bermuda grass Cynodon dactylon 9 23.33 12 14.63 Kanai nala Cyanotis axillaris - - 1 1.63 Total 40 45 T2 Nutsedge Cyperus rotundus 1 2.96 3 4.94 Alligator weed Alternanthera philoxeroides 21 39.51 Lambsquarte Chenopodium album 1 2.96 Harkuch Enhydra fluetuans 9 20.74 Barnyard grass Echinochloa crusgali 1 2.96 5 9.88 Jersey cudweed Gnaphalium affine 4 7.41 Goose grass Eleusine indica 4 7.41 Bermuda grass Cynodon dactylon 33 74.07 17 32.10 Total 45 55 T3 Scrab grass Digitaria spp 11 13.01 Nutsedge Cyperus rotundus 3 5.03 Alligator weed Alternanthera philoxeroides 20 24.39 Lambsquarter Chenopodium album 1 2.52 Harkuch Enhydra fluetuans 16 21.33 Barnyard grass Echinochloa crusgali 1 1.78 7 8.13 Jersey cudweed Gnaphalium affine - 4 4.88 Pig weed Amaranthu sviridis - 3 3.25 Bitter dock Rumex maritimus 1 1.63 Goose grass Eleusine indica 3 3.56 5 6.50 Bermuda grass Cynodon dactylon 29 55.35 31 37.40 Total 53 82 T4 Scrab grass Digitaria sanguinalis 3 4.76 Nutsedge Cyperus rotundus 3 4.23 9 16.67 Alligator weed Alternanthera philoxeroides 16 28.57 Lambs quarter Chenopodium album 1 2.12 Effect of integrated weed management practices on weed growth and yield of sorghum 82 Treatment English name Scientific name 25 DAE 45 DAE Number of weed m−2 Weed density (%) Number of weed m−2 Weed density (%) Harkuch Enhydra fluetuans 21 33.86 Barnyard grass Echinochloa crusgali 11 16.93 2 3 Jersey cudweed Gnaphalium affine 1 2.12 3 4.76 Goose grass Eleusine indica 1 2.12 Bermuda grass Cynodon dactylon 25 40.21 25 45.24 Total 63 56 T5 Scrab grass Digitaria sanguinalis 7 11.11 Nutsedge Cyperus rotundus 4 6.67 Alligator weed Alternanthera philoxeroides 25 42.22 Lambs quarter Chenopodium album 3 5.44 Harkuch Enhydra fluetuans 12 24.49 Barnyard grass Echinochloa crusgali 3 5.44 8 13.33 Jersey cudweed Gnaphalium affine 1 2.22 Goose grass Eleusine indica 4 8.16 Bermuda grass Cynodon dactylon 27 54.42 15 24.44 Total 49 60 T6 Scrab grass Digitaria spp 5 9.36 Nutsedge Cyperusrotundus 5 9.70 5 9.36 Alligator weed Alternantheraphiloxeroides 11 18.71 Lambs quarter Chenopodium album 1 2.42 Harkuch Enhydra fluetuans 9 16.97 Vetch Vicia satiua 4 7.02 Barnyard grass Echinochloa crusgali 7 12.12 3 4.68 Jersey cudweed Gnaphalium affine 3 4.68 Bitter dock Rumexm aritimus 7 11.70 Goose grass Eleusineindica 5 7.27 4 7.02 Bermuda grass Cynodon dactylon 27 48.48 15 25.73 Total 55 57 T7 Scrab grass Digitaria sanguinalis 4 3.77 21 11.47 Nutsedge Cyperus rotundus 11 10.06 4 2.15 Alligator weed Alternanthera philoxeroides 28 15.05 Hatisur Heliotra piumindicum 7 3.58 Paspalum grass Paspalum commergonii 3 1.43 Harkuch Enhydra fluetuans 23 21.38 Vetch Vicia Satiua 4 2.15 Barnyard grass Echinochola crusgali 15 13.84 17 9.32 Jersey cudweed Gnaphalium affine 7 6.29 47 25.09 Pig weed Amaranthus viridis 4 3.77 3 1.43 Wild radish Raphanus rahanistrum 4 3.77 Bitter dock Rumex maritimus 4 3.77 25 13.62 Goose grass Eleusine indica 7 6.29 11 5.73 Bermuda grass Cynodon dactylon 20 18.87 13 7.17 Lambs quarter Chenopodium album 7 6.29 3 1.43 Total 106 186 T1 = Two hand weeding at 25 and 40 days after sowing (DAS), T2 = Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (DAS), T3 =Atrazine @ 2 L ha−1 spraying as pre-emergence +weeding by BARI weeder at 25 days after sowing (DAS), T4 = Atrazine @ 2 L ha−1 spraying as post-emergence at 25 DAS + one hand weeding at 40 days after sowing (DAS), T5 = Pendimethalin @ 3 L ha−1spraying as pre-emergence +one hand weeding at 25 days after sowing (DAS), T6 = Pendimethalin @ 3 L ha−1 spraying as pre-emergence and T7= No weeding and no herbicide 83 Kakon et al. The present results are in agreement with the earlier findings of Priya and Kubsad (2013). Sorghum in very early stages of crop development grows slowly and competes weakly with weeds. This is the critical time and a small amount of weed in the field will cause a substantial reduction in yield (Saini et al., 2018). Hence the above treatments were effective in controlling the weeds in the earlier stages of the crop producing very low weed density. The weeds were very densely populated in the control plot. Herbicides in combination with good cultural practices would effectively reduce the density of the weed population in crop production (Greer and Denman, 1983). The dry matter of the weeds was influenced by different weed control strategies (Table 2). As the level of herbicides or weed control practices increases there was a great decrease in the dry matter accumulation by weeds (Shakoor et al., 2000). The treatment atrazine @ 2 L ha−1 as pre-emergence + one hand weeding at 25 DAS producing comparatively lower weed dry weight (21.0 g m−2 at 25 DAE and 30.7 g m−2 at 45 DAE at 2022-23 and 5.10 g m−2at 25 DAE and 63 g m−2 at 45 DAE at 2023-24). Other than the above treatments, dry matter accumulation by the weed was controlled effectively by two hand weeding @ 25 and 40 DAS, atrazine @ 2L ha−1 as post emergence + one hand weeding at 45 DAS and Pendimethalin @ 3L ha−1 as pre- emergence + one hand weeding at 25 DAS. The reason for the low dry matter accumulation by the weed in different weed management practices is because of their effectiveness in suppressing the weeds. These results were in similarity with the findings of Shakoor et al., (2000). On the other hand, highest weed dry matter was accumulated in the (T7) weeded plots (128.7 g m−2 at 25 DAE 314.7 g m−2 at 45 DAE at 2022-23 and 34.67 g m−2 at 25 DAE 342 g m−2 at 45 DAE at 2023-24) as the crops in the treatment was completely competed by the weeds because of the non-interference in the growth of weeds utilizing maximum resources (Deshmukh and Usadadia, 2017). Weed control efficiency (WCE) denotes the magnitude of weed reduction due to weed control treatment (Mani et al., 1973). The WCE was affected by different treatment. The highest WCE (84.4% at 25 DAE and 90.2% at 45 DAE at 2022-23 and 85.28% at 25 DAE and 81.58% at 45 DAE at 2023-24) was found in T2 (Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAS) treatment. Priya and Kubsad (2013), Pandey et al., 2001 and Thakur et al., 2016 have also obtained similar effect of various weed control treatments on WCE. Table 2. Weed dry weight (g m−2) and weed control efficiency at 25 DAE and 45 DAE as affected by different treatments during rabi seasons of 2022-23 and 2023-24 Treatment Dry weight of weed (g m−2) Weed control efficiency (%) 2022-23 2023-24 2022-23 2023-24 25 DAE 45 DAE 25 DAE 45 DAE 25 DAE 45 DAE 25 DAE 45 DAE T1 21.3 36.7 8.69 84.70 83.5 88.2 74.92 75.23 T2 21.0 30.7 5.10 63.00 84.4 90.2 85.28 81.58 T3 24.7 52.7 6.29 77.76 80.7 83.2 81.86 77.26 T4 25.3 38.7 6.78 81.00 80.4 87.5 80.44 76.32 T5 23.0 44.7 6.67 76.50 82.1 85.6 80.77 77.63 T6 25.7 37.3 6.10 94.50 80.2 87.9 82.40 72.37 T7 128.7 314.7 34.67 342.00 00 00 00 00 T1 = Two hand weeding at 25 and 40 days after sowing (DAS), T2 = Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (DAS), T3 =Atrazine @ 2 L ha−1 spraying as pre-emergence + weeding by BARI weeder at 25 days after sowing (DAS), T4 = Atrazine @ 2 L ha−1 spraying as post-emergence at 25 DAS + one hand weeding at 40 days after sowing (DAS), T5 = Pendimethalin @ 3 L ha−1spraying as pre-emergence +one hand weeding at 25 days after sowing (DAS), T6 = Pendimethalin @ 3 L ha−1spraying as pre-emergence and T7= No weeding and no herbicide Effect of integrated weed management practices on weed growth and yield of sorghum 84 Leaf Area Index Leaf area index (LAI) varied as influenced by different weed management practices (Fig. 2). Leaf area index did not differ at 30 DAE among the different weed management treatment but markedly differed at 60 DAE and up to 75 DAE. Treatment T2 (Atrazine @ 2 L ha−1 spraying as pre-emergence +one hand weeding at 25 DAS) and T5(Pendimethalin @ 3 L ha−1spraying as pre-emergence + one hand weeding at 25 DAS) gave the maximum LAI of 3.38 and 3.31 at 75 DAE followed by T1 and T4. Treatment T7 gave the lowest LAI of 1.89. Similar findings were obtained by Suseendran et al., (2019). Fig 2. Leaf area index (LAI) of sorghum at different DAE as influenced by different weed management. Here,T1 = Two hand weeding at 25 and 40 days after sowing (DAS), T2 = Atrazine @ 2 L ha−1 spraying as pre-emergence +one hand weeding at 25 days after sowing (DAS), T3 =Atrazine @ 2 L ha−1 spraying as pre-emergence +weeding by BARI weeder at 25 days after sowing (DAS), T4 = Atrazine @ 2 L ha−1 spraying as post-emergence at 25 days after sowing (DAS) + one hand weeding at 40 days after sowing (DAS), T5 = Pendimethalin @ 3 L ha−1spraying as pre-emergence +one hand weeding at 25 days after sowing (DAS), T6 = Pendimethalin @ 3 L ha−1spraying as pre-emergence and T7= No weeding and no herbicide Total dry matter production Total dry matter (TDM) accumulation in sorghum increased over time as influenced by different weed management methods (Fig.3). Difference in TDM production per unit area among the treatments started sharply from 60 DAE then increased rapidly up to 90 DAE and then increased slowly up to harvest. The maximum amount (1987 gm−2) of TDM per unit area was recorded in T2 (Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAE) followed by T5, T4 and T1 treatment and it was higher than other treatments throughout the growing period. The lowest TDM was observed in T7 (no weeding and no herbicide) treatment followed by T6 treatment. It might be due to better utilize the growth resources for growth and development as compared to other treatments and produced maximum TDM and T7 treatment produced the minimum TDM (1163 g m−2). Similar findings were also observed by BARI (2008). 0 0.5 1 1.5 2 2.5 3 3.5 4 30DAE 45DAE 60DAE 75DAE 90DAE At harvest L e a f a re a i n d e x Days after emergence T1 T2 T3 T4 T5 T6 T7 85 Kakon et al. Fig. 3. Total dry matter accumulation of sorghum at different DAE as influenced by different weed management. Here, T1 = Two hand weeding at 25 and 40 days after sowing (DAS), T2 = Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (DAS), T3 =Atrazine @ 2 L ha−1 spraying as pre-emergence + weeding by BARI weeder at 25 days after sowing (DAS), T4 = Atrazine @ 2 L ha−1 spraying as post-emergence at 25 days after sowing (DAS) + one hand weeding at 40 days after sowing (DAS), T5 = Pendimethalin @ 3 L ha−1spraying as pre- emergence +one hand weeding at 25 days after sowing (DAS), T6 = Pendimethalin @ 3 L ha−1 spraying as pre-emergence and T7= No weeding and no herbicide Crop growth rate Crop growth rate (CGR) values of sorghum increased progressively with time in different weed management methods (Fig.4) except T7 (No weeding and no herbicide). The CGR values declined from 90 DAE in T7 because of maximum crop weed competition. Treatment T2 (Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAS )gave the maximum CGR values of 45.89 gm−2 day−1 at 90-75 DAE, which was followed by T1(43.13g m−2 day−1), T4 (44.49 g m−2 day−1) and T5 (44.12 g m−2 day−1) treatment. Leaf area index, TDM and CGR values of sorghum under different weed management methods indicate that application of Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAS and Pendimethalin @ 3 L ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (DAS) had no adverse effect on sorghum. The results are in agreement with the reports of BARI (2008). 0 500 1000 1500 2000 2500 30DAE 45DAE 60DAE 75DAE 90DAE At harvest T o ta l d ry m a tt e r (g m -2 ) Days after emergence T1 T2 T3 T4 T5 T6 T7 Effect of integrated weed management practices on weed growth and yield of sorghum 86 Fig.4. Crop growth rate of sorghum at different DAE as influenced by integrated weed management. Here, T1 = Two hand weeding at 25 and 40 days after sowing (DAS), T2 = Atrazine @ 2 L ha−1 spraying as pre- emergence + one hand weeding at 25 days after sowing (DAS), T3 =Atrazine @ 2 L ha−1 spraying as pre-emergence + weeding by BARI weeder at 25 days after sowing (DAS), T4 = Atrazine @ 2 L ha−1 spraying as post-emergence at 25 days after sowing (DAS) + one hand weeding at 40 days after sowing (DAS), T5 = Pendimethalin @ 3 L ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (DAS), T6 = Pendimethalin @ 3 L ha−1 spraying as pre-emergence and T7= No weeding and no herbicide Plant height, yield and yield component of sorghum Plant population m−2, plant height at harvest, yield and yield components of sorghum were significantly affected by different weed management methods (Table 3). Plant population per unit area varied from 12 to 16 m−2. The highest population (16 m−2) was recorded from treatment T3, T4, T1, T5 and T6 which were identical to treatment T2. The lowest population (12 m−2) recorded in T7 treatment. The highest plant height (134.32 cm) was found in T5 (Pendimethalin @ 3 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAS) treatment which was followed by T1, T2, T3 and T4 treatments. The height of the plants was high on the above treatments is because that these treatments are effective in controlling the weeds hence offering less competition to the crop and the lowest plant height (109.67 cm) was observed in T7 (No weeding and no herbicide) treatment. This might be due to severe crop weed competition throughout the crop growth period, which adversely hampered the normal expansion of the crop (Patel et al., 2014). The longest (17.97 cm) panicle was observed in T2 (Atrazine @ 2 L ha−1spraying as pre-emergence + one hand weeding at 25 DAS) treatment which was followed by T1, T3, T4, T5 and T6 treatments and the shortest (14.50 cm) was in T7 treatment. Long panicle had higher number of grains panicle−1. The highest number of grain panicle−1 (948) was found in T2 (Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAS) treatment which was statistically similar to T1 and T5 treatments and the lowest number of grain panicle−1 (680) was observed in T7 treatment. The highest 1000-grain weight (35.34 g) was obtained in T5(Pendimethalin @ 3 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAS) treatment which was satistically similar to T1 and T2 treatments and the lowest (29.12g) was observed in T7 treatment. Similar findings was observed in Kumar et al., (2012). Significantly the maximum grain yield (3.64 tha−1) was found in T5 (Pendimethalin @ 3 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAS) treatment. However, it was 0 5 10 15 20 25 30 35 40 45 50 45-30DAE 60-45 DAE 75-60DAE 90-75DAE harves-90DAE C ro p g ro w th r a te (g m -2 d a y -1 ) Days after emergence T1 T2 T3 T4 T5 T6 T7 87 Kakon et al. statistically similar with Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAS (3.55 t ha−1), atrazine @ 2 L ha−1spraying as post-emergence at 25 DAS + one hand weeding at 40 DAS (3.36 t ha−1) and two hand weeding at 25 and 40 DAS (3.37 t ha−1), respectively and the minimum grain yield (1.74 t ha−1) was observed in T7 treatment. Vigorous weed growth and severe crop weed competition drastically reduced crop yield of the control plots. However, the reduction of yield under T7 treatment was 48% in compared with weed free throughout the growing period (T1) followed by the reduction of 52% from T5 treatment. The highest grain yield was attributed by the highest number of grain panicle−1 and 1000- grain weight (Table 3). The higher yields obtained on the above treatments was due to the fact that there was reduced crop weed competition as lesser or no weeds had been observed on the above treatments. Because of that reason the availability of soil moisture, nutrients, light and other resources to the plants was very high and hence promoted higher yields. These results are in corroboration with the earlier findings of Mishra et al. (2012), Ramakrishna et al. (1991) and Thakur et al. (2016). Table 3. Plant population m−2, plant height, yield and yield components of sorghum as affected by different weed management methods during Rabi season of 2022-24 Treatment Number of plant population m−2 Plant height at harvest (cm) Length of panicle (cm) . Grains panicle−1(No) 1000-grain weight (gm) Grain yield (t ha−1) T1 14 127.77 17.00 895 34.40 3.37 T2 16 134.32 17.97 948 34.55 3.55 T3 15 128.34 17.22 827 31.88 2.73 T4 15 126.11 17.56 870 34.19 3.36 T5 17 124.45 18.11 943 35.34 3.64 T6 15 114.56 16.35 813 29.93 2.58 T7 13 109.67 14.50 680 29.12 1.74 LSD (0.05) 2.20 10.54 1.79 50.16 0.27 2.74 CV (%) 8.05 4.79 5.94 3.30 4.71 5.01 T1 = Two hand weeding at 25 and 40 days after sowing (DAS), T2 = Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (DAS), T3 =Atrazine @ 2 L ha−1 spraying as pre-emergence + weeding by BARI weeder at 25 days after sowing (DAS), T4 = Atrazine @ 2 L ha−1 spraying as post-emergence at 25 day after sowing (DAS) + one hand weeding at 40 days after sowing (DAS), T5 = Pendimethalin @ 3 L ha−1spraying as pre-emergence + one hand weeding at 25 days after sowing (DAS), T6 = Pendimethalin @ 3 L ha−1spraying as pre-emergence and T7= No weeding and no herbicide Cost return performance Economic analysis of different weed management practices on sorghum production was done (Table 4). From the cost and return analysis it was found that the highest gross return (Tk. 109300 ha−1) and gross margin (Tk. 54370 ha−1) was recorded in T5 (Pendimethalin @ 3 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAS). The highest average yield with highest gross return was obtained from T5 treatment and this was followed by application of Atrazine 2 L ha−1 + one hand weeding at 25 DAS (T2). The lowest gross margin was in T7 treatment (Tk. 5485 ha−1). The highest BCR was obtained from T5 (Pendimethalin @ 3 L ha−1 as pre-emergence + one hand weeding at 25 DAS) (2.01) followed by T2 (1.96) treatment and the lowest benefit cost ratio was in T7 (No weeding and no herbicide) (1.12) treatment. Hence, both the treatments (Pendimethalin @ 3 L ha−1 and Atrazine 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 DAS) gave the highest return and BCR. Effect of integrated weed management practices on weed growth and yield of sorghum 88 Table 4. Cost and return analysis of sorghum as affected by different weed management method in 2022- 23 and 2023-24 Treatment Yield (t ha−1) Gross return (Tk. ha−1) Cost of cultivation (Tk. ha−1) Gross margin (Tk. ha−1) BCR T1 3.37 101220 62730 38490 1.61 T2 3.55 106525 54380 52145 1.96 T3 2.73 81910 55345 26565 1.48 T4 3.36 100760 56325 44435 1.79 T5 3.64 109300 54370 54930 2.01 T6 2.58 77275 52230 25045 1.48 T7 1.74 52265 46780 5485 1.12 T1 = Two hand weeding at 25 and 40 days after sowing (DAS), T2 = Atrazine @ 2 L ha−1 spraying as pre-emergence + one hand weeding at 25 days after sowing (DAS), T3 =Atrazine @ 2 L ha−1 spraying as pre-emergence + weeding by BARI weeder at 25 days after sowing (DAS), T4 = Atrazine @ 2 L ha−1 spraying as post-emergence at 25 day after sowing (DAS) + one hand weeding at 40 days after sowing (DAS), T5 = Pendimethalin @ 3 L ha−1spraying as pre-emergence + one hand weeding at 25 days after sowing (DAS), T6 = Pendimethalin @ 3 L ha−1spraying as pre-emergence and T7= No weeding and no herbicide. 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