Sequential Herbicide Applications Research Articles

Varietal Tolerance of Cucurbitaceous Crops with S-metolachlor Applied Postemergence

Cucurbit crops comprise ∼25% of the vegetable acreage in the mid-Atlantic and Northeastern United States. However, options for postemergence weed control in these crops are limited. Overlapping herbicides is a technique that involves sequential applications of soil-applied residual herbicides to lengthen herbicidal activity before the first herbicide dissipates. Residual herbicides such as S-metolachlor will not control emerged weeds, but weed control efficacy may be extended if these herbicides are applied after crop emergence, but before weed emergence occurs. Currently S-metolachlor is not labeled for broadcast applications over cucurbit crops. Greenhouse studies were conducted to evaluate pumpkin, cucumber, and summer squash variety response to varying S-metolachlor rates. S-metolachlor was applied at 1.42 and 2.85 lb/acre at the two-leaf stage of pumpkin and 0.71, 1.42, 2.85, and 5.7 lb/acre at the two-leaf stage of cucumber and summer squash. Cucumber showed a greater response to S-metolachlor with up to 67% injury observed at 5.70 lb/acre. S-metolachlor applications to pumpkin and summer squash resulted in less than 6% injury, regardless of application rate or crop variety. S-metolachlor applied at 2.85 lb/acre reduced pumpkin and cucumber dry weight 6% and 19%, respectively, but did not reduce squash dry weight. S-metolachlor reduced cucumber dry weight 78% for all varieties. Pumpkin varieties ‘Munchkin’ and ‘Baby Bear’ exhibited a 23% difference in dry weight, but no other differences were observed among other varieties because of S-metolachlor applications. Summer squash varieties ‘Respect’ and ‘Golden Glory’ exhibited a 31% difference in dry weight, but no other differences were observed among other varieties. Results show that pumpkin and summer squash demonstrated good crop safety when S-metolachlor was applied as a broadcast treatment after crop emergence. However, caution should be urged when applying this herbicide to cucumber.

Growth and productivity of maize (Zea mays) as influenced by sequential and combined application of tank mix herbicides

The experiment was conducted during 2021–22 at Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand to evaluate the impact of sequential and tank mix application of pre- and post-emergence herbicide on weed dynamics and maize productivity. The study was comprised of 9 treatments viz. Weedy (T1 ); Weed free (T2 ); Pre-emergence (PE) application of Atrazine -1 kg a.i./ha fb hand weeding (T3 ); PE application of Atrazine - 0.75 kg a.i./ha fb Post Emergence (Post E) application of Topramezone - 25.2 g a.i./ha (T4 ); PE application of Atrazine - 0.75 kg a.i./ha fb Post E application of Tembotrione - 120 g a.i./ha (T5 ); PE application of Atrazine - 1.0 kg a.i./ha fb Post E application of Topramezone - 25.2 g a.i./ha (T6 ); PE application of Atrazine - 1.0 kg a.i./ha fb Post E application of Tembotrione - 120 g a.i./ha (T7 ); Early Post E application of Topramezone - 25.2 g a.i./ha + Atrazine - 0.75 kg a.i./ha (T8 ) and Early Post E application of Tembotrione - 120 g a.i./ha + Atrazine - 0.75 kg a.i./ha (T9 ). Eleusine indica, Echinochloa colona, Digitaria sanguinalis and Eragrostis japonica were dominant among grassy weeds whereas broad leaf weeds included Cucumis melo, Phyllanthus niruri, Cleome viscosa and Commelina benghalensis. Cyperus rotundus was dominant among sedges. Topramezone - 25.2 g a.i./ha + Atrazine - 0.75 kg a.i./ha Early Post E resulted significantly lower total weed density and was similar to other herbicidal treatments. The highest grain yield (7.2 t/ha) was recorded in a weed-free crop that was similar to all herbicidetreated crops and significantly higher than the weedy crop. Tank mix application of atrazine - 0.75 kg a.i./ha with tembotrione 120 g a.i./ha or topramezone 25.2 g a.i./ha at 15 DAS can be suggested owing to higher grain yield and profits for farmers while lowering the dose and expenses involved in manual weeding and spraying atrazine separately.

Sequential herbicide application coupled with mulch enhances the productivity and quality of winter onion (Allium cepa L.) while effectively controlling the mixed weed flora

Weed control poses substantial difficulties for winter season onion (Allium cepa L.) cultivation in the north-western Indo-Gangetic Plains, primarily due to the constrained efficacy of the existing herbicides. To address this issue, a 2-year field study was conducted to assess the efficacy of pre- and post-emergence herbicides (pendimethalin, ethoxysulfuron, imazethapyr, and quizalofop-p-ethyl) individually and in combination with crop residue mulch for weed control in winter onion. The results revealed that using herbicides or mulches in isolation did not provide satisfactory weed control. However, the integration of natural mulch with pendimethalin followed by quizalofop-p-ethyl application proved to be the most effective weed control strategy, resulting in the least reduction in bulb yield (10.3%) compared to other treatments. On the contrary, combinations of pendimethalin with ethoxysulfuron or imazethapyr showed adverse effects on the onion crop and inflicted the highest yield losses among all treatments (78.6 and 83.4%, respectively). However, the combination of pendimethalin with quizalofop-p-ethyl coupled with crop mulch resulted in season-long weed control and over 80% bulb yield (36.58 t/ha) gains compared to the weed-free condition. These findings emphasize the efficacy of combining herbicides and mulches as an integrated weed management strategy for onions. By adopting such integrated approaches, farmers could improve weed control while maintaining bulb yield and quality, reducing the risks associated with herbicide resistance, and promoting sustainable onion production in the north-western Indo-Gangetic Plains.

Weed management in Bt. Cotton through sequential and tank mix application of different herbicides

Weed management in Bt. Cotton through sequential and tank mix application of different herbicides

A systematic review of chemical weed management in peanut (Arachis hypogaea) in the United States: challenges and opportunities

AbstractHerbicides are the primary tool for controlling weeds in peanut (Arachis hypogaea L.) and are crucial to sustainable peanut production in the United States. The literature on chemical weed management in peanut in the past 53 yr (1970 to 2022) in the United States was systematically reviewed to highlight the strengths and weaknesses of different herbicides and identify current research gaps in chemical weed management. Residual weed control in peanut is achieved mainly with dimethenamid-P, ethalfluralin, pendimethalin, and S-metolachlor. More recently, the use of the protoporphyrinogen oxidase inhibitor flumioxazin and acetolactate synthase inhibitors, such as diclosulam, for residual weed control in peanut has increased considerably. Postemergence broadleaf weed control in peanut is achieved mainly with acifluorfen, bentazon, diclosulam, imazapic, lactofen, paraquat, and 2,4-DB, while the graminicides clethodim and sethoxydim are the major postemergence grass weed control herbicides in peanut. Although several herbicides are available for weed control in peanut, no single herbicide can provide season-long weed control due to limited application timing, lack of extended residual activity, variability in weed control spectrum, and rotational restrictions. Therefore, effective weed management in peanut often requires herbicide mixtures and/or sequential application of preplant-incorporated, preemergence, and/or postemergence herbicides. However, the available literature showed a substantive range in herbicide efficacy due to variations in environmental conditions and flushes of weed germination across years and locations. Despite the relatively high efficacy of herbicides, the selection of herbicide-resistant weeds is another area of increasing concern. Future research should focus on developing new strategies for preventing or delaying the development of resistance and improving herbicide efficacy within the context of climate change and emerging constraints such as water shortages, rising temperatures, and increasing CO2 concentration.

Effects of sequential and combined application of tank-mix herbicides on weed growth and productivity of maize (Zea mays)

The field experiment was conducted at G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand during kharif season 2021–22 to evaluate the effects of tank-mix herbicides on weeds and maize (Zea mays L.) in order to determine the optimum dosage, application time and combinations of herbicides for maize. Based on the findings, it could be concluded that weed-free conditions are just as effective as atrazine applied with tembotrione or topramezone through sequential or tank mix application for reducing weeds effectively and increasing grain yield. Tank mix treatments of topramezone (25.2 g a.i./ha) and tembotrione (120 g a.i./ha) with reduced dose of atrazine (0.75 kg a.i./ha) should be employed by farmers since it not only removes weeds effectively but, also offers a better environment for maize to grow providing high profits for farmers. It also lowers the dose and expenses involved in manual weeding and spraying atrazine separately.

Does narrow row spacing suppress weeds and increase yields in corn and soybean? A meta-analysis

AbstractNarrow row spacing (<76 cm) could improve crop competitiveness, suppress weeds and might provide yield advantage. Many studies have been conducted to evaluate the impact of narrow row spacing; however, no quantitative synthesis of these studies exists. The objectives of this meta-analysis were to (1) quantify the overall effect of narrow row spacing (<76 cm) on weed density, biomass, control, weed seed production, and yield in corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] compared with 76-cm row spacing, and (2) assess the influence of agronomic management decisions (tillage type, weed management, herbicide application frequency and time) on effect of narrow row spacing on weed suppression and corn and soybean yield. We compiled 1,904 pair-wise observations from 35 studies conducted in 12 states in the United States during 1961 to 2018. Averaged across individual observations, narrow row spacing suppressed weed density by 34%, weed biomass by 55%, and weed seed production by 45%, while it improved weed control by 32% and crop yield by 11% compared with 76-cm row spacing. Narrow row spacing in soybean suppressed weed density by 42%, weed biomass by 71%, and increased crop yield by 12% compared with 76-cm row spacing. Although narrow row spacing had a nonsignificant effect on response variables in corn, the number of studies (n = 1 to 6) and observations (n = 1 to 59) addressing each response variable were limited. Tillage type (conventional and reduced) did not influence the response of weed density, control, and seed production in narrow row spacing; however, weed biomass and weed seed production were more greatly reduced with the sequential application of herbicides compared with a single application. Thus, narrow row spacing in soybean can be integrated with other options for management of herbicide-resistant weeds.

Effect of Herbicidal Weed Management on Productivity and Profitability of Summer Cowpea

Background: The presence of weeds in cowpea reduced the yield to the tune of 60-82% depending on the weed flora and density. The critical period of weed competition in cowpea was 20-25 DAS. Therefore it is essential to control weeds effectively to harness the maximum yield potential of the crop. To manage weeds in cowpea it is also important to determine the efficacy of pre and post-emergence herbicides. Sequential application of herbicides in a short duration crop not only increases the cost of production but also create cumbersome in its application. Therefore ready mix herbicides are now becoming popular among farming community. These new ready mix herbicides need to be tested for its bio-efficacy to manage weeds and its effect on crop productivity and symbiotic characters of cowpea. Therefore, a field experiment was carried out to evaluate the impact of herbicides on the productivity and profitability of summer cowpea (Vigna unguiculata L.) at Agronomy Main Research Farm, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha (India) during summer season. Methods: The experiment was laid out at Agronomy Main Research Farm, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha (India) during the summer season of 2021 and2022 in a randomized block design (RBD) comprised of eight treatment with three replications. Standard procedures were followed for the observations and statistical analysis of the data. Result: The experimental results revealed that ready mix of pendimethalin+imazethapyr-750 g/ha significantly control the mixed flora of weeds which resulted significant increase in growth and yield. Ready mix application of pendimethalin + imazethapyr 750 g/ha registered the highest benefit to cost ratio.

Effect Of Sequential Application Of Pre And Post-Emergence Herbicides On Dynamics Of Weeds Associated With DSR System Andrice-Growth And Sustained Yield

The sustained rice yield plays an important role in the country’s GDP. The diverse weed flora is a potential biotic threat to the sustained yield in the DSR system. The crop faces severe competition the resources from its beginning (germination of crop seedlings) to the panicle initiation with the diverse weeds flora as it grows quickly in moist conditions, resulting in severe yield losses up to 65 per cent. Thus, an effective and economical weed control strategy in DSR is often required to overcome the losses. In such situations, sequential application of herbicides may provide broad-spectrum weed control in DSR. A field experiment was conducted on silty loam soils to assess the herbicidal effects on weed dynamics and growth & yield productivity of direct-seeded rainy (Kharif) rice at Agronomy Research Farm of Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya (U.P.) during the years, 2016 and 2017. The field trial was carried out in Randomized complete block design (RCBD) with three replications and twelve treatments. The treatments consisted of nine pre & post-emergent herbicide combinations along with three distinct controls, i.e. a) Hand weeding (at 20 & 40 DAS), b) Weed Free (weeding at every 15 days interval from seedling to the PI stage), and c) Weedy Check. The results of the field study revealed that the weed-free plots recorded the highest weed control efficiency, and they registered the least weeds density and dry weight of weeds associated with direct seeded rice fields. However, the application of herbicides, namely, pendimethalin (1000 g a.i. ha-1) as pre-emergent and Bispyribac-Na (1000 g a.i. ha-1) as post-emergent coupled with a hand weeding at 40 DAS provided the statistically comparable results to weed-free and is effectively controlled the diverse weed flora by 81.9-84.5 per cent in DSR system. And both the treatments gave significantly better growth (plant height, number of tillers, dry matter, LAI) and yields (grain and straw) of rice as compared to the weedy-check. Among the diverse weeds associated with the DSR fields, sedges were dominant as compared to broad leaves and grasses. The study also recorded the rice-grain yield reduction by 40.9 per cent due to the presence of diverse weed flora in weedy check plot as to weed-free plot.

Weed management in broadcast sesame (Sesamum indicum L.) through sequential application of herbicides

A field experiment was conducted to study the effect of sequntial application of pre-and post-emergence herbicides on growth, nutrient uptake and yield of broadcast sesame on sandy loam soils. Eleven weed managementpractices consisting of pre-emergence application of pendimethalin @ 750 g/ha, oxyfluorfen @ 75g/ha and oxadiargyl @ 75g/ha alone and sequential application ofthese pre-emergence herbicides followed by post-emergenceapplication of quizalofop @ 50g/ha and propaquizafop @ 60g/ha including two hand weedings at 20 and 40 DAS and unweeded check were compared in randomized block design with three replications. Results revealed that thelowest density and dry weight ofweeds with lesser weed index were recorded in the plots treated with pre-emergence application of oxyfluorfen @ 75g/ha followed by quizalofop @ 50 g/ha applied at 20 DAS. The same weedmanagement practice recorded significantly higher stature of growth parameters and yield attributes. The increase in seed yield of sesame was 38.0 per cent with sequential application of oxyfluorfen @ 75g/ha followed byquizalofop @ 50 g/ha applied at 20 DAS compared to unweeded check. Heavy weed infestation in unweeded check plots resulted in incresed weed nutrient uptake upto 44.6, 5.6 and 34.0 kg of N, P and K/ha, respectively. Oxadiargyland oxyfluorfen @ 75 g/ha each showed phytotoxicity score of '4' and '3' respectively in 0 to 10 scale. Pre-emergence application of oxyfluorfen @ 75 g/ha followed by propaquizafop @ 60g/ha applied at 20 DAS recorded the highest benefit-cost ratio.

Control of Multiple-Herbicide-Resistant Canada Fleabane With Fall, Spring, and Sequential Herbicide Applications in Winter Wheat

Limited information exists on the efficacy of pyrasulfotole/bromoxynil, fluroxypyr/halauxifen-methyl + MCPA EHE, and clopyralid applied in the fall, spring, or sequentially [fall followed by (fb) spring] for the control of multiple-herbicide-resistant (MHR) Canada fleabane in winter wheat under Ontario environmental conditions. Three field experiments were initiated in the autumn of 2020 and 2021 for a total of 6 site-years to evaluate fall- and spring-applied herbicides and their sequential applications for the control of MHR Canada fleabane in winter wheat in Ontario. Pyrasulfotole/bromoxynil applied in the fall, spring, or sequentially controlled MHR Canada fleabane 83, 99, and 100%, respectively at 8 weeks after the spring application (WAB); the spring and sequential applications provided better control than the fall application. Fluroxypyr/halauxifen + MCPA and clopyralid applied in the fall, spring, or sequentially controlled MHR Canada fleabane 97 to 100% and 99 to 100%, respectively at 8 WAB. Based on orthogonal contrasts the spring and sequential herbicide applications provided greater control than the fall application (8 WAB). MHR Canada fleabane interference reduced winter wheat yield up to 27% in this study. Based on orthogonal contrasts reduced MHR Canada fleabane interference with the fall application resulted in 17% higher winter wheat yield than when herbicide application was delayed to the spring. Although MHR Canada fleabane was controlled very effectively with clopyralid winter wheat yield was lower, presumably due to crop injury; this observation will have to be explored further in future research. Results from this study indicate that pyrasulfotole/bromoxynil and fluroxypyr/halauxifen + MCPA applied in the fall can be used to effectively control MHR Canada fleabane and minimize winter wheat yield loss due to weed interference.

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.

The Effects of Agronomic Management in Different Tillage Systems on the Fall Growth of Winter Oilseed Rape

The article presents the results of a three-year study, which analyzed agronomic management in the production of winter oilseed rape (WOSR) in different tillage systems. The effects of weed control and growth regulation in fall on the number of rosette leaves, epicotyl length, root collar diameter, taproot length, rosette weight, root weight, and the overwintering success of WOSR plants in different tillage systems were determined in the study. A field experiment was conducted at the University’s Agricultural Experiment Station in Bałcyny in north-eastern Poland in three growing seasons (2016/2017–2018/2019). The experiment had a mixed 21 × 32 factorial design with two replications, where one factor was evaluated at two levels, and two factors were evaluated at three levels. The experimental factors were: A—tillage: (A0) strip-till, (A1) low-till, and (A2) conventional tillage; B—weed control: (B0) pre-emergent, (B1) foliar, and (B2) sequential; C—growth regulation: (C0) none and (C1) in fall. Winter oilseed rape plants developed rosettes with the optimal morphometric parameters in the strip-till system. Sequential and foliar application of herbicides decreased the dry matter (DM) content of leaf rosettes (by approx. 18%). The application of the growth regulator in BBCH stages 14–15 increased taproot length by 3%.

Efficacy of Herbicides on Nutrient Uptake of Crop, Weed and Its Impact on Soil Microflora of Irrigated Maize (Zea mays L.)

Aim: Field experiment was conducted to study the suitable weed management methods to check the nutrient depletion by weeds, check the dynamics of microbial population and in relation to improve the biomass stover yield of maize (Zea mays L.).
 Study Design: This experiment laid out in a randomized block design and 8 different weed management treatments with three replications.
 Place and Duration of Study: Field experiment was conducted at Agricultural College and Research Institute, Madurai, Tamil Nadu Agricultural University, Tamil Nadu in kharif 2019.
 Methodology: TNAU maize hybrid CO-6 was used for this experiment. Treatments were application of pre-emergence herbicide atrazine at 0.25 kg/ha or pendimethalin 1 kg/ha applied singly on 3 days after sowing and in combination with post-emergence herbicide tembotrione 120 g/ha or halosulfuron methyl 90 g/ha on 25 DAS, weed free check, unweeded check in maize crop. Weed nutrient depletion and microbial population was analysed in laboratory.
 Results: The application of pre-emergence atrazine 0.25 kg/ha followed by post-emergence tembotrione 120 g/ha effective in controlling of grasses and BLW and enhance the nutrient uptake of maize. The stover maize yield increased with application of herbicides and sequential application of herbicides achieved 88% improved stover yield over unweeded check. Sequential application of herbicides initially reduce the population of soil microflora but the population gradually build up in all the herbicide applied plots at 60 days after application.
 Conclusion: Based on the results of the experiment, it was concluded that pre-emergence atrazine 0.25 kg/ha followed by post emergence tembotrione 120 g/ha effective in controlling of weeds and enhance the nutrient uptake and stover yield of maize without much adverse impact on soil microbial population.

Herbicidal weed-management options for dry direct-seeded rice (Oryza sativa) in North-Eastern Plains of India

A field experiment was conducted during the rainy (kharif) seasons of 2017 and 2018 at Regional Station of the ICAR-Indian Agricultural Research Institute, Pusa, Samastipur, Bihar, to study the effect of herbicides in controlling mixed weed flora in direct-seeded rice (Oryza sativa L.). The experimental results revealed that, the alone and sequential application of herbicides significantly reduced the weed density and biomass of complex weed flora. The growth and yield attributes, viz. plant height at maturity, effective tillers/m2 , 1,000grain weight, grains/panicle and panicle length, were significantly influenced by application of herbicides. Weed-free condition resulted in significantly highest grain yield (4.49 t/ha). Among different herbicidal treatments, application of pendimethalin @ 1,000 ml/ha followed by (fb) tank-mix application of bispyribac sodium (25 g/ha) + pyrazosulfuron (15 g/ha) resulted in higher plant height (110.7 cm), higher number of effective tillers (320.0/m2 ), grains/panicle (132.2), ear length (29.8 cm), grain yield (4.49 t/ha), net returns (` 70,600/ha) and benefit : cost ratio (1.67), which was superior to rest of the treatments. Application of pendimethalin (1,000 ml/ha) fb tank-mix application of bispyribac sodium (25 g/ha) + pyrazosulfuron (15 g/ha) significantly reduced the weed density (56.8/m2 ) and weed biomass (26.6 g/m2 ).

Effect of herbicides on weed dynamics, soil fertility, energetics and productivity of upland rice in an acidic subtropical soil of the Eastern Himalayas, India

ABSTRACT Weed management in upland rice under subtropical climate with high rainfall is challenging. The diverse weed flora in upland rice ecosystem emerges in several flushes, necessitating sequential application of herbicides. A 4-year study conducted in Meghalaya (950 m above sea level), India indicated that sequential application of Cyhalofop butyl [2-{4-(4-cyano-2-fluorophenoxy) phenoxy} propionic acid, butyl ester (R)], a grass weed killer high efficacy low volume herbicide applied 80 g ha−1 at 25 days after sowing (DAS) and 2,4-D, a broadleaf weed killer herbicide applied 0.75 kg ha−1 at 35 DAS was effective for weed control and produced significantly higher grain yield (3572 kg ha−1) of rice with the highest weed control efficiencies than other treatments. Application of Pretilachlor followed by (fb) 2,4-D or Fenoxaprop-p-ethyl fb 2,4-D yielded significantly higher chlrophyll (chl) a, chl b and total leaf chl content compared with other herbicides at 90 DAS. The highest net energy (111,443 MJ ha−1), energy profitability and benefit:cost ratio was recorded with sequential application of Cyhalofop butyl and 2,4-D. Thus, sequential application of Cyhalofop butyl and 2,4-D could provide a sustainable weed management option in upland rice under high rainfall conditions in the Eastern Himalayas, India.

Efficiency of post-emergence herbicides for enhancing growth and yield of hybrid maize (Zea mays) in Kandahar, Afghanistan

A field experiment was conducted at research farm of the Afghanistan National Agricultural Science and Technology University (ANASTU), Kandahar, Afghanistan, in randomized complete- block (RCBD) design during summer 2017, to evaluate the effect of post-emergence (PoE) herbicides in maize (Zea mays L.). Results revealed that sequential application of atrazine @ 1,500 g/ha as pre-emergence followed by (fb) tembotrione @ 120 g/ha as post emergence (PoE) 25 days after sowing (DAS) recorded significantly higher plant height and leaf-area index at 60 and 90 days after sowing (DAS), while dry-matter accumulation and the yield attributes as grains/row, grain/cob and grain weight/cob at harvesting stages. Weed infestation in hybrid maize caused 35.8% yield loss compared to weed-free control. Application of the weed-management treatments increased the maize yield by 35.2% (11.6 – 51.2) over unweeded check. Significantly higher grain yield (6.50 t/ha) was recorded with sequential application of atrazine (1,500 g/ha) as pre-emergence followed by tembotrione (120 g/ha) at 25 DAS, which was at par with pendimethalin (1,000 ml/ha) as pre-emergence followed by atrazine (750 g/ha) + 2,4-D amine (400 g/ha) at 25 DAS as PoE (6.21.3 t/ha) and atrazine (1,500 g/ha) as pre-emergence fb 2,4-D amine (400 g/ha) at 25 DAS (6.12 t/ha). Therefore, the sequential application of pre-and post-emergence herbicides could be opted for enhancing growth and yield and weed control of hybrid maize in Afghanistan and similar ecologies.

Sequential application of herbicides for weed management in direct-seeded basmati rice

Sequential application of herbicides for weed management in direct-seeded basmati rice

Performance of sequential application of pre and post-emergence herbicides for management of weeds in aerobic rice (Oryza sativa)

A field experiment was conducted during the rainy (kharif) season of 2014 and 2015 at Zonal Agricultural Research Station, V.C. Farm, Mandya, Karnataka, India, to study the performance of sequential application of herbicides in aerobic rice (Oryza sativa L.). Among the weed-management practices, hand-weeding at 20, 40 and 60 days after sowing (DAS) resulted in significantly lower density and dry weight of all categories of weeds, ensuing higher grain yield (5.57 and 5.42 t/ha, respectively); this was closely followed by pre-emergence application of pyrazosulfuron ethyl @ 25 g/ha and by post-emergence application of bispyribac-sodium @ 25 g/ha at 20 days after sowing (5.20 and 5.12 t/ha, respectively) during both the years. However, the higher net returns (`48,210 and 47,040/ha, respectively) and benefit: cost ratio (2.62 and 2.58, respectively), during both the years were obtained from sequential application of herbicide treatment. Uncontrolled weed growth caused about 51% reduction in grain yield of aerobic rice during 2014 and 2015.

Effect of Sequential Application of Herbicides on Weed Management, Productivity and Nutrient Uptake of Direct Seeded Rice

Effect of Sequential Application of Herbicides on Weed Management, Productivity and Nutrient Uptake of Direct Seeded Rice