Minimum Weed Density Research Articles

Interactive effect of nutrient and weed management in transplanted rice (Oryza sativa L.) for enhancing the productivity in Eastern India

A field experiment comprising three nutrient and six weed management practices was conducted in strip plot design with three replications during 2019 and 2020 at Odisha University of Agriculture & Technology (OUAT), Bhubaneswar, India to assess the effect of the treatments on weed dynamics, productivity and nutrient uptake by crop and weed. Averaged over both years, among nutrient management practices, the soil test based dose (STD: 100-40-40 N-P2O5-K2O kg ha-1) + green manuring (GM) of dhaincha recorded the minimum weed density of 45.3 and 64.2 number m-2 and weed biomass of 19.2 and 37.6 g m-2 at 30 and 60 days after transplanting (DAT), respectively and the minimum N, P and K uptake of 6.4, 2.0 and 6.8 kg ha-1 by weed and the maximum N, P and K uptake of 113.6, 23.2 and 122.6 kg ha-1 by the crop, respectively. Among weed management practices, bensulfuronmethyl + pretilachlor (PE) fb HW on 35 DAT produced the minimum weed density of 25.15 and 20.66 number m-2, the minimum weed biomass of 7.70 and 8.08 g m-2 at 30 and 60 DAT, respectively and the minimum N, P and K uptake of 2.4, 0.5 and 2.6 kg ha-1 by weed and the maximum N, P and K of 117.9, 25.3 and 263.7 kg ha-1 by crop, respectively. Among nutrient management practices, the STD + GM proved to be the best with the maximum grain yield of 5562 kg ha-1. whereas the application of bensulfuronmethyl + pretilachlor (PE) fb HW on 35 DAT excelled over other weed management practices with the maximum grain yield of 5907 kg ha-1 registering 17.71 and 47.64% higher grain yield compared to the STD and the weedy check, respectively.

Herbicidal weed management options for pigeon pea(Cajanus cajan) grown in southeastern Rajasthan

A field experiment was carried out during the kharif seasons of 2020–21, 2021–22 and 2022–23 at Kota, Rajasthan, to study the effect of post-emergence herbicides on productivity of pigeonpea [Cajanus cajan (L.) Millsp]. The results indicated that the minimum weed density and dry weight, and the highest yield attributes, yields, and net return of pigeonpea were obtained under weed free plot. All the herbicidal treatments significantly reduced the weed density and biomass compared to the weedy check. However, application of pendimethalin 30 EC @ 0.75 kg /ha (PE) fb Imazethapyr 10 SL @ 100 g/ha at 20–25 DAS + one inter-cultivation at 50 DAS recorded significantly higher plant height (1.82 m), pods/branch (22.96), pods/plant (206.3), weed control efficiency (84.39% at 60 DAS), grain yield (1,868 kg/ha), net return (` 87.66 x 103 /ha) and B: C ratio (3.35) over weedy check. This leads to the 61.73% higher pigeonpea grain yield over the weedy check plot. Hence it can be inferred that the ap- plication of pendimethalin 30 EC @ 0.75 kg /ha (PE) fb Imazethapyr 10 SL @ 100 g/ha at 20–25 DAS + one inter- cultivation at 50 DAS is an efficient weed control method for profitable cultivation of pigeonpea in south eastern Rajasthan.

Integrated Weed Management in Summer Sesame (sesumun indicum L.)

A field research was evaluated at the Seed Technology, S. D Agricultural University, Sardarkrushinagar-385506, Banaskantha (North Gujarat) in the year between summer 2019 to 2021 to study the effect of weed management practices in summer sesamum. Experimental plot was loamy sand in texture with low organic carbon and available N, medium in available P2O5 and high in available K2O.
 Treatments were weed free (IC fb HW at 20 and 40 DAS), weedy control, pendimethalin 30 EC 0.750 kg/ha PE application fb IC+HW at 30 DAS, pendimethalin 30 EC1.0 kg/ha PE application fb IC+HW at 30 DAS, oxadiargyl 6 EC 75 g/ha PE fb IC + HW at 30 DAS, oxadiargyl 6 EC 90 g / ha PE fb IC+HW at 30 DAS, quizalofop-ethyl 5 EC 40 g/ha PoE 20 DAS fb IC+ HW at 40 DAS, quizalofop-ethyl 5 EC 50 g/ha PoE at 20 DAS fb IC+ HW at 40 DAS, pendimethalin 30 EC 0.75 kg/ha PE fb quizalofo-pethyl 5 EC 40 g/ha at 30 DAS and pendimethalin 30 EC 1.0 kg/ha PE fb quizalofop-ethyl 5 EC 40 g/ha at 30 DAS.
 The results revealed that significantly maximum seed yield (0.90 t/ha), stalk yield (2.14 t/ha), number of capsules per plant (73.1) and number of branches per plant (5.2) were obtained under weed free (IC fb HW at 20 and 40 DAS) treatment with maximum net realization (₹52322/ha).
 Minimum weed density at harvest/m2 and weed dry weight/m2 (67.17/m2 and 32.51g/m2) and maximum weed control efficiency (71.62%) were found under weed free (IC fb HW at 20 and 40 DAS).

Weed Management Studies in Wheat (Triticum aestivum L.) Through New Herbicide Molecule Aclonifen 600 SC under Climate Changing Era

Changing climate aggregates, the problem of weed management by rapid weed flora shift and resistance development. In these conditions, the best option is to use new herbicide molecules with a diverse mode of action and a wider application time window. Thus, an herbicidal trial was conducted during the Rabi 2019-20 at Agricultural Research Farm, BHU, Varanasi. The experiment was laid out in RCBD design with 8 treatments viz., control (W1), aclonifen 600SC @ 1.05 kg a.i./ha PE (W2) and early POE (W5),aclonifen 600SC @ 1.2 kg a.i./ha PE (W3) and early POE (W6), pendimethalin 30% EC @ 1.25 kg a.i./ha PE (W4), sulfosulfuron 75% WG @ 0.025 kg a.i./ha POE (W7), Farmer practice-2 hand weedings at 20 and 40 DAS (W8) and replicated thrice. Among different treatments aclonifen 600 SC @ 1.25 kg a.i./ha as pre and early post-emergence applied treatments recorded minimum weed density, weed dry matter production, highest weed control efficiency and crop persistence index. The same treatments registered better crop growth performance, and profitable yields.

Effect of different weed management practices on production of spring maize in Dang, Nepal

The study was carried out at Lamahi-8, Satbariya, Dang to evaluate the effect of different weed management practices on the production of spring maize. The experiment was carried out in a Randomized Complete Block Design using three replications and seven treatments. Rampur hybrid 10 variety and early post emergence (EPoE) herbicide were used in the experiment. The treatment consisted of single as well as combined weed management methods as T1: Broadcasting-One hand weeding, T2: Broadcasting-Herbicide, T3: Line sown- One hand weeding, T4: Line sown-Herbicide + one hand weeding, T5: Line sown- Mini tiller weeder, T6: Line sown- herbicide + mini tiller and T7: Line sown- One hand weeding + mini tiller. The experiment result showed that the combined application of early post emergence herbicide and mini tiller resulted the highest grain yield (8.62 Mt/ha) with minimum total weed density at 60 DAS (41.33/m2) and at harvest (68/m2) thus resulting minimum weed dry weight at 60 DAS (5.45 g/m2) and at harvest (10.64 g/m2). Sixteen different weed species belonging to 9 different families were identified in the experimental field. The highest benefit: cost (3.37) was obtained in the treatment Line sown-Herbicide + mini tiller weeder which was significantly higher compared to other treatments. Among the treatments applied, one with the application of herbicide in combination with mini tiller weeder was found to be the most effective one that resulted in the minimum weed density and minimum dry weight, higher grain and biological yield with the highest benefit cost ratio thus proving to be the most economical one. At the same time, application of mini tiller weeder as a single method was found to be the next better alternative for weed control in spring maize that could benefit the farmers in comparison to other single weed management practices.

Evaluating sequential application of pre and post emergence herbicides in direct- seeded rice

A field experiment was conducted at Agriculture Research Farm, Bihar Agricultural University, Sabour, Bhagalpur, Bihar during kharif season of 2018-19 to study the effect of different herbicides on weed species, growth attributes and yields of direct seeded rice. The experiment comprised of 11 treatments based on weed management practices. The 11 treatments were lone application of pendimethalin and pyrazosulfuron as pre-emergence herbicides while others were as post-emergence at 20 days after sowing i.e. pyrazosulfuron @ 25 g/ha PE, pendimethalin @1000 g/ha PE, pyrazosulfuron @ 25 g /ha PE fb 2,4-DEE @ 750 g/ha POE, pyrazosulfuron @ 25 g /ha PE fb bispyriba-Na @ 25 g/ha POE, pyrazosulfuron @ 25 g/ha PE fb bispyribac-Na @ 20 g/ha + pyrazosulfuron @ 20 g/ha POE, bispyribac-Na @ 25 g/ha POE, bispyribac-Na @ 20 g/ha + pyrazosulfuron @ 20 g/ha POE, ethoxysulfuron @ 15 g/ha + pyrazosulfuron @ 20 g /ha POE, halosulfuron @ 67.5 g/ha + azimsulfuron @ 30 g/ha POE, hand weeding thrice and weed check. Among all the herbicidal treatments, the minimum weed density (5.13 m-2), dry weight (4.82 g m-2), highest grain yield (5.41 t/ha) and benefit cost ratio (1.9) were recorded with application of pyrazosulfuron @ 25 g/ha PE fb bispyribac-Na @ 20 g/ha + pyrazosulfuron @ 20 g/ha POE.

Novel method to manage weeds in the rainfed groundnut (var. VRI 8 and TMV 14) using nano encapsulated herbicide formulations

The groundnut crop harbours heavy weed infestation due to its small stature and slow growing nature. The current weed management practices of hand weeding and use of commercial herbicides are unsuitable because of high labour cost and inadequate moisture availability to activate herbicides. In order to release the herbicide in a smart way, this experiment aimed to study the efficacy of encapsulated herbicides . Field experiments were conducted during Kharif 2021 and late Rabi 2022 under rainfed conditions in randomised block design with three replications. The treatments consisted of sulfentrazone, oxyfluorfen, diclosulam and metolachlor in both commercial and encapsulated form using two doses, hand weeding at 20 and 40 DAS, weed free plot and weedy check. Minimum weed density (28.33 and 17.30 No./m2 at 90 DAS during Kharif and late Rabi respectively) and weed dry weight (65.33 and 61.25 g/m2 at 90 DAS during Kharif and late Rabi respectively) were observed in hand weeding at 20 and 40 DAS (T19) followed by diclosulam @ 25 g ha-1 with encapsulation (T7). Maximum weed density and weed dry weight was observed in metolachlor @ 1 kg/ha with encapsulation (T8). Higher productivity was observed in hand weeding at 20 and 40 DAS (T19) (1802 kg ha-1 and 1753 kg ha-1 pod yield during Kharif and late Rabi respectively) and higher profitability was obtained in diclosulam @ 25 g ha-1 with encapsulation (T7) (1.80 and 2.01 B:C ratio during (Kharif and late Rabi respectively). Nano-encapsulated herbicides can thus significantly improve weed control in rainfed groundnut.

Weed growth and productivity of summer greengram (Vigna radiata L.) under sole and sequential application of herbicides

Greengram is a short stature crop, whose growth is sluggish during the early period which makes it susceptible to very intense weed competition from a divers weed flora. An investigation was carried out during the summer season, 2021 at Agricultural Research Station, Binjhagiri, Siksha ‘O’ Anusandhan, deemed to be University, Bhubaneswar, India to evaluate the efficacy of sole and sequential application of herbicides on weed growth, productivity and profitability of summer greengram. Ten treatments comprise of sole and sequential application of pendimethalin, imazethapyr at different doses, two hand weeding and weedy check were replicated thrice in the randomized block design. The major weed flora found in the experimental area were Poa annua, Digitaria sanguinalis, Melochia corchorifolia, Aeschynomene afraspera and Grangea maderaspatana. Study revealed that among the herbicidal treatments, application of pendimethalin @ 1000 g/ha at 1 day after sowing (DAS) fb imazethapyr @ 75 g/ha at 20 DAS registered significantly the minimum weed density and biomass along with higher values of weed control efficiency, which was statistically at par with pendimethalin @ 750 g/ha at 1 DAS fb imazethapyr @ 75 g/ha at 20 DAS treatment. The highest productivity (8.16 q/ha) was significantly recorded under twice hand weeding at 15 and 35 DAS, which was found to maintain statistically similar yield levels with pendimethalin @ 1000 g/ha at 1 DAS fb imazethapyr @ 75 g/ha at 20 DAS (8.05 q seed/ha) and pendimethalin @ 750 g/ha at 1 DAS fb imazethapyr @ 75 g/ha at 20 DAS (7.97 q seed/ha). However, the sequential application of pendimethalin @ 750 g/ha at 1 DAS fb imazethapyr @ 75 g/ha at 20 DAS revealed the highest B:C ratio (1.93) in terms of profitability of greengram. Thus, sequential application of pendimethalin @ 750 g/ha at 1 DAS fb imazethapyr @ 75 g/ha at 20 DAS appeared to be promising for effective weed management, higher productivity and profitability in summer greengram.

Comparative efficacy of different mulching materials to enhance growth and development and to control weed infestation in cotton

Abstract
 The present study was based on the hypothesis that mulching materials can directly control weeds and indirectly crop growth and development by improving soil fertility. The present study was conducted to evaluate the “Comparative efficacy of different mulching materials to enhance growth and development and to control weed infestation in cotton” at Student’s Experimental Farm, Department of Agronomy, Sindh Agriculture University Tandojam, during Kharif season, 2016, in a three, replicated randomized complete block design (RCBD). The net plot size was 4m x 3m (12m-2). There were three cotton varieties (Haridost, Shahbaz, and Sind-1), three mulching materials (wheat straw, sunflower, and banana leaves, each applied at 12 t ha-1), and a control without any mulching treatment. The study revealed that the maximum sympodial branches plant-1 (27.93), opened bolls plant-1 (47.53), the weight of seed cotton plant-1 (124.55 g), seed index (8.73 g), seed cotton yield (5394.4 kg ha-1), staple length (30.33 mm), ginning out-turn percentage (37.96%) and oil contents (22.45%) were recorded in Sindh-1 with banana leaves as mulching material. The same treatment caused the maximum leaf area (136.56 cm-2), and leaf area index (4.92 cm) in Haridost. The minimum weed density (55.00 m-2), weed fresh (293.6 g m-2) and dry biomass (122.52 g m-2) with maximum weed control (81%) was recorded with banana leaves as mulching material in Sindh-1. It can be concluded that mulching with banana leaves at 12 t ha-1 significantly reduced the weeds infestation, resulting in enhanced growth, yield, and physiological parameters of cotton crop..

Efficacy of weed control treatments on weeds and productivity of chickpea under Jatropha based agroforestry

A field experiment was conducted at Research Farm, Department of Forestry, JNKVV, Jabalpur during Rabi season 2019-20 to find out the effect of weed management on weeds and productivity of Chickpea under Jatropha based Agroforestry. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications and 12 herbicidal treatments consisted of Pendimethalin (1000 g ha-1), Imazathaper (900 g ha-1), Atrazine (1000 g ha-1), Metribuzin (300 g ha-1), Oxyflorfen (100 g ha-1), Pendimethalin (500 g ha-1) fb Imazathaper (450 g ha-1), Pendimethalin (500 g ha-1) fb Oxyflorfen (50 g ha-1), Metribuzin (150 g ha-1) fb Oxyflorfen (50 g ha-1), Atrazine (500 g ha-1) fb Metribuzin (150 g ha-1), Imazathaper (450 g ha-1) fb Atrazine (500 g ha-1), hand weeding (30 DAS) and Weedy check (control). The field was infested with 4 major weed species Medicago denticulata Willd., Vicia sativa L., Cynodon dactylon L., and Cyperus rotundus L. Minimum weed density per m2 (7.53) and weed dry weight (5.42 q ha-1), was found under hand weeding 30DAS over weedy check. Minimum dry weight of weeds was found under hand weeding (30 DAS) 5.42q ha-1 as compare to weedy check (control) 16.84q ha-1). The highest weed control efficiency was found in hand weeding (30DAS) 89.75%, Pendimethalin (1000 g ha-1) 78.50 %, Atrazine (1000 g ha-1) 67.67 %, Oxyflorfen (100 g ha-1) 66.83 %, and Metribuzin (150 g ha-1) fb Oxyflorfen (50 g ha-1) 65.41%. The loss of grain yield was significantly reduced where weeds were control by Pendimethalin (1000 g ha-1) 11.16 %, and Metribuzin (150 g ha-1) fb Oxyflorfen (50 g ha-1) 11.19 %. Amongst the different herbicidal treatments higher seed yield was found under Pendimethalin (1000 g ha-1) 12.54 q ha-1, higher stover yield was found under Pendimethalin (1000 g ha-1) 37.46 q ha-1, higher crop biomass was found under Pendimethalin (1000 g ha-1) 50.00 q ha-1 and higher harvest index was found under Pendimethalin (1000 g ha-1) 24.99 % as compared to other treatments. The perusal data showed that higher harvest index was found under hand weeding (30DAS) 25.06 % which was significantly superior over weedy check (control) 18.74 % and rest of the weed control treatments. Pre emergence herbicides and hand weeding can further enhance the weed suppressive effect of the crop under Jatropha based Agroforestry.

On-field assessment of mulching materials for weed control and its impact on yield and economics in okra (Abelmoschus esculentus (l). moench)

On-field assessment trail was conducted by Krishi Vigyan Kendra, Madhopur at different places in West Champaran District of Bihar during two consecutive years i.e., 2019–2020 and 2020–2021 regarding to assess the efficacy of mulching materials to reduce the weed infestation and enhancing yield and economics of okra. The treatments consisted of three different mulching materials (mulching with black polythene sheet, mulching with paddy straw and mulching with sugarcane leaves) and one control plot was also kept where farmers practice (hand weeding and no mulch) was carried out. The effect of mulching materials on okra yield was found significant. The highest okra yield (149.11 kg/ha) was obtained under mulching with black polythene sheet followed by mulching with paddy straw (117.39 kg/ha) and mulching with sugarcane leaves (111.06 kg/ha) whereas, it was lowest in farmer's practice (94.78 q/ha). Minimum weed density (5.45/m2) was recorded significantly under mulching with black polythene sheet whereas maximum was under farmer's practice (74.06/m2). Maximum average benefit cost ratio was achieved under mulching with black polythene sheet (4.56) followed by mulching with paddy straw (3.77) and mulching with sugarcane leaves (3.69) However, minimum was under farmer's practice (2.90). Mulching with black polythene sheet was found significantly superior over all the treatments including framer's practice in terms of days after sowing to first harvest, fruit weight (yields) and total number of harvests. It is concluded that using black polythene mulch as soil covering was significantly increased yield of okra due to maintain soil moisture content and reduction of weed flora density. This would sustainably increase the income as well as the livelihood of the farmers.

Effect of weed management practices and organic sources of nitrogen supplementation on weed density and yield of wheat

The different weed control methods (two hand weeding at 25 and 45 days after sowing (DAS) and one hand weeding at 25 DAS along with unweeded control ), organic sources of nitrogen (vermicompost, poultry manure, city manure and FYM) and their interaction were compared for their efficiency on various weed species and yield of wheat. Two hand weeding (W2) gave significantly maximum weed control. This was followed by one hand weeding at 25 DAS and control. These weed control methods significantly enhanced the yield and yield components of wheat. Among organic sources of nitrogen vermicompost (M1) recorded minimum weed density, weed dry weight and maximum yield, followed by poultry manure, city manure and FYM.

Effect of rice residue on weed suppression and yield performance of boro rice

The experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during the period from December 2017 through May 2018 to study the effect of rice residue on weed suppression and yield of boro rice. The experiment consisted of four different rice residue treatments such as no rice residue, 2.5, 5 and 7.5t ha-1rice residue, and five different herbicidal treatments such as no herbicide (H0), 25% of the recommended dose (RD), 50% RD, 75% RD and 100% of RD. The experiment was laid out in a randomized complete block design with three replications. Seven weed species belonging to five families infested the experimental plots. Weed density and weed dry weight were significantly affected by incorporation of rice residue and herbicidal treatment. The maximum weed growth was noticed with no rice residue incorporation and application of no herbicide. The minimum weed density and dry weight were found in incorporation of 5 t rice residue ha-1 and application of 100% of RD of herbicide treatment. Rice residue exerted significant effect on yield and yield contributing characters like plant height, number of total tillers hill-1, number of effective tillers hill-1 and grain yield. The highest grain yield (4.89 t ha-1) was recorded with the incorporation of 2.5 t ha-1 rice residue which was statistically identical with5 and 7.5 t ha-1 rice residues. The grain yield (5.70 t ha-1) produced by 75% of RD of herbicide was the highest among the other herbicidal treatments. The highest number of effective tillers hill-1 (12.80), 1000-grain weight (21.07), grain yield (5.87 t ha-1) and straw yield (7.21 t ha-1) were observed with the incorporation of 5 t rice residue ha-1 and 75% of the RD of herbicide treatment. Results of this study indicate that rice residue showed potentiality to inhibit the growth of weed and exerted significant effect on the yield of boro rice. Rice residue @ 5 t ha-1 with application of herbicide of 75% RD might be suggested to use for effective weed management and better grain yield of boro rice.

Effect of integrated weed management practices on growth and yield of Direct Seeded rice under puddle condition of Agro-climatic situation of Chhattisgarh

The present investigation was conducted at Instructional Farm of Indira Gandhi Krishi Vishwavidyalaya, Raipur (C.G.) India during the kharif season (June-October) 2006. The experiment was laid out in randomized block design comprised of eight treatments of various combinations of different herbicides viz. T1:PIH 2023 10% SC 15 g a.i/ha at 18 DAS; T2 : PIH 2023 10% SC 20 g a.i/ha at 18 DAS; T3 : PIH 2023 10% SC 25 g a.i/ha at 18 DAS; T4 : PIH 2023 10% SC 30 g a.i/ha at18 DAS; T5 : PIH 202310% SC 60 g a.i/ha at 18 DAS T6 : Almix 20% WP 4 g a.i/ha 18 DAS; T7 :Control (unweeded check) and T8 : Hand weeding at 30 DAS with three replications. Rice cultivar “IR-64” was grown as a test crop. The growth performance of Rice i.e. plant height, Number of tillers(m-2), Number of effective tillers(m-2), dry matter accumulation plant-1, was higher under PIH 2023 10% SC 25 g a.i/ha as compared to other weed management practices. Wher as the minimum growth of rice recorded under unweeded. Maximum grain yield and straw yield was under PIH 2023 10% SC 60 g a.i/ha Echinochloa colona, Cyperus spp., F. miliaceae, L. hyssopifolia were the pre-dominant weeds in experimental plot. Minimum weed density was noted under post emergence application of Almix 4 g ha-1 and PIH 2023 25 g ha-1 at 20, 40, 70 and 90 DAS. Whereas, at harvest lower dry matter of weeds and highest weed control efficiency was recorded under Almix 4 g ha-1 (T6), PIH 2023 25 g ha-1 and PIH 2023 60 g ha-1, respectively. It was found effective to control broad spectrum of weeds viz., grasses, sedges and forbs.

Effect of planting patterns and weed management practices on weed dynamics and nutrient mining in runner bean (Phaseolus coccineus L.) + Maize (Zea mays L.) intercropping

A field experiment entitled “Planting pattern and weed management in maize (Zea mays L.) + runner bean (Phaseolus coccineus L.) intercropping system” was conducted during the rabi season of 2016-17 at Agronomy Main Research Farm, Bhubaneswar. The experiment was laid out in split plot design with planting patterns in the main plot and weed management practices in the sub plot. ‘Shriram 9220’ maize hybrid and ‘Raikia local’ variety of runnerbean were used as test crops. The study revealed that P4- maize 100% + runner bean 100% in the same row recorded the minimum weed density and dry weight and maximum weed smothering efficiency. While, weed management practices, W3-Pendimethalin 1.0 kg/ha + 1 manual weeding also recorded the minimum weed density and dry weight and maximum weed control efficiency. Significantly higher nutrient of content in the maize grain and stover was recorded in maize 100% + runner bean 50% in separate rows among planting patterns and W3-pendimethalin 1.0 kg/ha + one manual weeding at 25 DAS among weed management practices. For runner bean, maize 100% + runner bean 100% in same row gave significantly higher pod and haulm nutrient content. However, the maximum uptake of N, P and K was in sole crops of runner bean and maize respectively due to its higher yield.

Weed management practices in rice (Oryza sativa) + brahmi (Bacopa monnieri) intercropping system

A field study was carried out during two consecutive kharif seasons 2015–2016 at Norman E Borlaug Crop Research Centre, G B Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, to evaluate the effect of different weed management practices and different row ratios on yield, yield attributes and economics of the rice (Oryza sativa L.) + brahmi (Bacopa monnieri) intercropping system. The dominant weed floras were Echinochloa crus-galli, Echinochloa colona, Alternanthera sessilis, Caesulia axillaris and Cyperus rotundus. Among different herbicides, pendimethalin followed by (fb) cyhalofop-butyl fb, one hand weeding at 45 days after sowing in 2:1 row ratios had minimum weed density (16.83 and 9.82/m2), dry weight (7.35 and 3.97 g/m2) and highest weed control efficiency (73.36 and 83.45%). Intercropping of rice with brahmi, exhibited greater potentiality and realized significantly higher plant height, dry matter accumulation, number of nodes, number of branches, number of panicles/m2 and 1000 grain weight. Dry herbage yield of brahmi and grain yield were highest in sole crop of rice (5.3 and 6.56 t/ha) and brahmi (2.07 and 2.35 t/ha). Furthermore, pendimethalin fb cyhalofop-butyl fb one hand weeding at 45 DAS in 1:1 ratio of rice and brahmi gave highest net returns (255426.1 and 317163.1/ha) and benefit cost ratio (10.1 and 11.07) and also high value of land equivalent ratio (1.76 and 1.85) and area time equivalent ratio (0.88 and 0.92) during both years.

Application of Bromoxynil+MCPA+Metribuzin at Varied Doses for Broad-Spectrum Weed Control in Forage Maize (Zea mays L.)

Weed control is one of the crucial factors to achieve higher yield of good quality forage maize. A field trial was conducted during summer 2013 to investigate the effect of bromoxynil+MCPA+metribuzin (Valent 470 EW pre mixed formulation) application at varied doses to control weeds in forage maize (Zea mays L.) at Agronomy Research Area, University of Agriculture, Faisalabad, Pakistan. Application of bromoxynil+MCPA+metribuzin @ 470, 528.75 and 587.50 g a.i/ha was made after emergence of weedsand crop. A check with no application and hand hoeing was included for comparison. The experiment was conducted with four replications under randomized complete block design. The data regarding the weed parameters, yield and yield components of maize were recorded. The results revealed that among the herbicide treatments minimum weed density (three weeks after sowing 35.75 m2 and at harvest 12.25/m2) and dry biomass (20.80 g/m2) was observed with the application of bromoxynil+MCPA+metribuzin @ 587.50 g a.i./ha. Same herbicidal treatment caused significant increase in plant height (248.75 cm), stem diameter (1.45 cm), fresh weight (467.25g) and forage yield (31.47%) of maize. Therefore, use ofbromoxynil+MCPA+metribuzin @ 587.50 g a.i./ha is the best option to manage broad leaved as well as grassy weeds in forage maize to get higher yield of forage .

Effect of cultivars and weed management practices on weeds, productivity and profitability in zero-till direct-seeded rice (Oryza sativa)

A field study was carried out during the two consecutive kharif seasons of 2012 and 2013 at the Agricultural Research Farm, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, to evaluate the effect of cultivars and weed management practices on weed dynamics, yield attributes, yields and economics in zero-till direct-seeded rice (Oryza sativa L.). The dominant weed flora were Echinocloa colona, Echinocloa crus-galli, Cynodon dactylon, Cyperus rotundus, Cyperus iria, Caesulia auxillaries and Eclipta alba. Among rice cultivars, Arize-6129 had minimum weed density (425.9 and 480.1/m) and dry weight (76.7 and 86.4 g/m2), and maximum of grain yield (4.29 and 4.12 t/ha) during both the years, respectively. Among the weed management practices, application of bispyribac sodium + azimsulfuron (25 g +35 g/ha) + 0.25% NIS (post-emergence) at 15-20 DAS proved to be most effective in minimizing the weed density, weed dry weight and increased rice grain yield (4.33 and 4.16 t/ha, respectively). Arize-6129 produced maximum net returns (`40402 and 37804/ha) and benefit: cost ratio (1.61 and 1.51) and economic efficiency (`316 and 298/ha day), respectively during both the years. Among weed management practices, application of bispyribac sodium + azimsulfuron (25 g +35 g/ha) + NIS (0.25%) was the most economical and efficient.

Influence of Tillage Systems and Selective Herbicides on Weed Management and Productivity of Direct-Seeded Rice (Oryza sativa)

ABSTRACT: Weeds cause considerable damage to rice crop. To ascertain the influence of different weed management practices under different tillage systems, a field experiment was conducted during 2014-15. Experimental design was RCB with split-plot arrangement and with a net plot size of 6 x 2 m. Three tillage systems viz; zero tillage with glyphosate application and conventional tillage with and without stale seed bed, and seven weed management treatments viz; weedy check, manual weeding, oxadiargyl as pre-emergence, pyrazosulfuron as pre-emergence, pyrazosulfuron as post-emergence, fenoxaprop-ethyle + sodium fluoride as post-emergence and fenoxaprop-ethyle + sodium fluoride as post-emergence. Results revealed that all treatments including tillage systems and herbicides significantly (p<0.05) affected weed density and weed dry biomass. Minimum weed density (229.22, 159.22 and 127.77 m-2) and weed dry biomass (68.01, 49.29 and 41.08 g m-2) at 30, 45 and 60 DAS (days after sowing) were recorded for pyrazosulfuron (as pre-emergence), respectively, followed by fenoxaprop-ethyle + sodium fluoride (as post-emergence). Maximum 1000-kernel weight and kernel yield (19.15 g and 3.45 ton ha-1) were recorded for weed free treatments and it was 12 and 57% higher than weedy check. Maximum net benefit and benefit to cost ratio (USD$ 817 ha-1 and 1.76, respectively) were recorded for pyrazosulfuron applied at either pre- or post-emergence stage under zero tillage system. Conclusively, pyrazosulfuron (as pre-emergence) and fenoxaprop-ethyle + sodium fluoride (as post-emergence) gave the best weed control under conventional tillage with stale seed bed system, while pyrazosulfuron exhibited maximum benefit-cost ratio under zero tillage system.

Weed Management in Direct Seeded Rice Grown under Varying Tillage Systems and Alternate Water Regimes

ABSTRACT: In direct seeded rice (DSR), flushes of weeds are encountered, and mostly subsequent herbicides need to apply to control weeds that appear later. A farmer friendly approach was hypothesized in present study to integrate the management strategies for water, soil and cost effective weed free rice production. Efficacy of various herbicides in weed control to improve the performance of aerobic rice grown under varying tillage and alternate water regimes was evaluated. Five weed management techniques (weedy check, weed-free, pendimethalin followed by manual weeding, pendimethalin + bispyribac sodium (BS) + bensulfuron (B) and pendimethalin + MCPA) were carried out within the alternate wetting and drying (AWD) regimes (15 and 20 cm depth) under two tillage systems (zero and conventional). All the herbicide treatments reduced the weed intensity as compared to weedy check, however minimum weed density and dry biomass was observed in pendimethalin at 40 and 60 days after sowing, respectively. Under conventional tillage, weed free plots showed maximum leaf area index, leaf area duration and crop growth rate. Maximum plant height, 1000-kernel weight and kernel per panicle along with less percentage of abortive, chalky and opaque kernels were recorded in pendimethalin followed by BS+B as compared to weedy check plots. Among the herbicides application, pendimethalin followed by BS+B gave highest benefit to cost ratio and net benefits under both AWD regimes. Overall, application of pendimethalin followed by BS+B is an efficient and economic approach to reduce weed infestation which results in improved yield of aerobic rice.