Total Weed Density Research Articles

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.

Effect of Mesotrione 40% SC on Weed Growth, Yield and Economics of Maize (Zea mays L.)

Newer herbicides are required to reduce the losses cause by the weeds in maize crop. Therefore, a field experiment was conducted during kharif 2019 at Research Farm, AICRP on Forage Crops, Department of Agronomy, Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur (Madhya Pradesh) to study the effect of different weed management practices on productivity of Maize (Zea mays L.). The experiment was conducted in randomized block design with eight treatments (six herbicidal treatments with hand weeding twice at 20 and 40 DAS and weedy check) replicated thrice. Observations were recorded for various weed parameters and crop growth parameters. All the weed management treatments significantly reduced the total weed density and total dry weight of weeds as compared to weedy check. Among herbicidal treatments, mesotrione 350 g ha-1 recorded the lowest total weed density and total dry weight of weeds as compared to other herbicides. While highest total weed density and total dry weight were recorded under weedy check treatment. Significantly higher growth parameters and yield attributing traits were recorded with the application of mesotrione 350 g ha-1 which resulted in higher grain and stover yields (2447.22 and 21804.72 kg ha-1) followed by mesotrione 300 g ha-1. Maximum net returns and Benefit: Cost ratio was also obtained with the application of mesotrione 350 g ha-1.

Weed Dynamics of Fodder Maize as Influenced by Different Herbicides

The advancements in fodder maize cultivation practices over the past few years, has paved a change in the makeup of weed associations. This made it necessary to incorporate new, effective herbicides in the struggle against maize's primary weeds. Therefore, a field experiment was conducted at Research Farm, AICRP on Forage Crops, Department of Agronomy, JNKVV, Jabalpur (Madhya Pradesh) during Kharif season 2019 to devise an appropriate combination of herbicides required for the control of the complex weed diversity in fodder maize. The field experiment was laid out in randomized block design (RBD) with ten treatments (eight herbicidal combinations along with hand weeding twice at 20 and 40 DAS and a weedy check) and replicated thrice. Observations were recorded on the weed parameters and fodder yield of maize. Among monocots, the experimental field was infested with Echinochloa colona, Commelina communis and Digitaria sanguinalis. Phyllanthus niruri and Eclipta alba were dominated among dicots. Among all herbicidal treatment, topramezone 35 g/ha plus atrazine 250 g/ha was found to be significantly superior in reducing total weed density (9.49/m2, 11.50/m2) and total weed dry weight (6.43 g/m2, 7.91 g/m2) at 30 and 45 DAS, respectively and recorded the lowest weed index (1.82%). Also, the maximum green fodder yield (472.68 q/ha) was recorded in topramazone 35 g/ha + atrazine 250 g/ha compared to other treatments. Overall, this study indicated that the combination of topramazone 35 g/ha + atrazine 250 g/ha could be an alternative approach to hand weeding and alone herbicides in fodder maize.

The Effect of Sorghum Bicolor Extracts and Lower Rate of Trifluralin Herbicide on Weeds in Vigna Sinensis L.

Allelopathic influence of Sorghum bicolor cultivar (Cv Enqatht) on the growth and development of a few weeds test (Beta vulgaris L., Chenopodium album L., Amaranthus retroflexus L., and Malva rotundifoloia L.) and weeds company with Vigna Sinensis L. crop were investigated. All treatments significantly (0.05) reduced total weed density by (32.4) and total dry biomes by 57.1)n gm above control at a rate of 4 gm kg-1 soil results pots experiment. However, when the 8gm.kg-1 of soil was put to pots altered with Sorghum bicolor residual residue, the decrease was much greater. The second experiment was done using a R.C.B.D design to investigate the effects of Sorghum bicolor decarase (rate 800 g. meter-2) on the development of Vigna Sinensis L. crop and companion weeds, compared to a control treatment and a full rate of Trifluraln herbicide (50 percent) (2.4 L.h-1). The field experiment result showed a trend of Sorghum bicolor residue at 800 gm/kgm effect on number of company weed of Vigna Sinensis L., crops by (38, 4.7, 24, 10.67, 38.7) and biomass (68, 63.7, 61.7, 22.33, 27.3) gm compared to control treatment, however, this reduction was further increased when the 50 percent full rate of herbicide was applied to plots amended with Sorghum bicolor residues. In comparison to the control treatment, the application of Sorghum bicolor residues in conjunction with a 50 percent rate of trifluralin boosted biological yield and harvest index of Vigna Sinensis L. crops. Conclusion: Sorghum bicolor residue might be employed as a realistic and ecologically sound weed management and soil enhancement strategy for Vigna Sinensis growing crops.

Residual effects of herbicides on weed interference and productivity in wheat (Triticum aestivum) under a conservation agriculture-based onion (Allium cepa)–wheat cropping system

A field experiment was conducted during the rainy (kharif) and winter (rabi) seasons of 2015–16 and 2016–17 at the ICAR-Indian Agricultural Research Institute, New Delhi, to evaluate the effects of conservation agriculture (CA) and carryover weed management on weed interference and crop productivity of wheat [Triticum aestivum (L.) emend Fiori & Poal] in an onion (Allium cepa L.)–wheat system. Three conventional and conservation tillage and 7 weed-management treatments were laid out in a split-plot design, with 3 replications. The CA-based zero-till raised-bed system with residue retention (ZTRB + R) resulted in significant reduction in total weed density and biomass compared to conventional till flat bed (CTFB), which led to higher weed control efficiency (11%), grain (4.02 t/ha) and straw yield (4.24 t/ha), and net returns 46000 `/ha in the year 2016–17. The zero-till flat bed with residue (ZTFB + R) and ZTRB + R led to an increase in wheat grain yield by 5.1 and 3.6%, and net returns by 28 and 18% than CTFB respectively. Among the herbicidal treatments, the pendimethalin followed by (fb) ethoxysulfuron resulted in the highest reduction in weed density (29 and 34%) and weed dry weight (55 and 56%) in both years, and the pendimethalin fb quizalofop was comparable with it in these regards. The pendimethalin fb quizalofop- or ethoxysulfuron- treated plots provided higher wheat grain yield (4.24 t/ha), net returns 49000 `/ha and net benefit: cost (B: C) in the year 2016–17. The pendimethalin fb ethoxysulfuron had higher residual effect on weeds in wheat but inflicted severe phytotoxicity to onion in previous season that reduced onion yield significantly. Therefore, the pendimethalin fb quizalofop application to onion is most preferred considering onion and wheat crops safety and may be adopted under zero-till raised-bed for higher productivity and profitability in onion–wheat cropping system.

Screening of Herbicides in Transplanted Finger Millet [Eleusine coracana (L.) Gaertn

Background: Weeds smother the finger millet due to crop’s slow growth during the initial stages which reduces the yield substantially by 5-70%. Intensive use of herbicides is gaining popularity among the farmers now a days due to its effectiveness in controlling weeds, timeliness and reduced cost. Methods: The current field experiment was conducted at Tamil Nadu Agricultural university during kharif season, 2021 under irrigated condition with twelve herbicide treatments laid out in Randomized Complete Block Design (RCBD) with three replications. Result: Pre-emergence application of pyrazosulfuron ethyl 15 g ha-1 significantly reduced the total weed density and total weed dry weight at 90 days after transplanting over all the other herbicides used. This treatment also considerably improved the plant parameters such as plant height, total number of tillers, plant dry matter production, Grain and stover yield and yield parameters such as productive tillers, ear head weight of transplanted finger millet which was statistically followed by the application of pendimethalin 750 g ha-1 as pre-emergent spray. Similar trend was followed in case of net returns and B: C ratio. while lower plant parameters were observed with the application of tembotrione 12 g ha-1.

Impact of Weed Management Practices on the Weed Dynamics, Nutrient Uptake Pattern of Weeds and Direct Seeded Rice

Herbicide based weed management is the emerging and effective method for controlling the weed flora of direct seeded rice. Weed growth often has an impact on crop development by interfering with plant nutrients. A two-year weed experiment with twelve treatments was set up at the University of Agricultural Sciences in Bangalore, Karnataka, India to know the effect of weed management practices on weed and nutrient dynamics in direct seeded rice. Significantly lower total weed density and biomass was observed with bispyribac sodium 10 SC 40 g a.i. ha-1 as post emergence which recorded statistically at par values with bensulfuron methyl + pretilachlor 6.6 GR 660 g a.i. ha-1 as pre-emergence during both the years of study. The allelochemicals used in the study performed well over unweeded control but it was far less when compared with chemical herbicides. Nutrient uptake by the direct seeded rice (82.17, 31.76 and 68.83 kg ha-1 NPK in 2020 and 89.38, 38.84 and 75.62 ha-1 NPK in 2021, respectively) and grain yield (4.98 t ha-1 in 2020 and 4.99 t ha-1 in 2021, respectively) was also reported to be higher with bispyribac sodium 10 SC 40 g a.i. ha-1 as post emergence which was on par with bensulfuron methyl + pretilachlor 6.6 GR 660 g a.i. ha-1 as pre-emergence. As the nutrient uptake by the crop and weeds are negatively correlated, the same treatments have recorded lower nutrient removal by the weeds. Higher weed biomass and rapid nutrient removal by weeds had resulted in poor soil nutritional status in unweeded control compared to all other treatments. Application of bispyribac sodium 10 SC 40 g a.i. ha-1 as post emergence or bensulfuron methyl + pretilachlor 6.6 GR 660 g a.i. ha-1 as pre-emergence were considered to be best management practices for weed management under direct seeded rice.

Using Post-Emergence Herbicides in Combination with the Sowing Date to Suppress Sinapis arvensis and Silybum marianum in Durum Wheat

Wild mustard (Sinapis arvensis L.) and milk thistle (Silybum marianum (L.) Gaertn.) are two competitive broad-leaved weeds commonly found in cereals in Europe, while several weed species have developed resistance to the main herbicides that are applied on these crops. Thus, the implementation of integrated weed management (IWM) programs is of great importance. Field experiments were conducted based on a split-plot design with two factors (sowing date and herbicides). Our results showed that the density of wild mustard and milk thistle was higher in the early sowing compared to the late sowing, while the total weed density was up to 75% higher in early sowing. Moreover, the herbicides florasulam + 2.4-D and bromoxynil + 2.4-D exhibited high efficacy (>98%) against milk thistle and wild mustard, while tribenuron-methyl and florasulam + clopyralid provided greater efficacy in the late sowing compared to the early sowing. Among the four herbicides, the lowest dry biomass and grain yield of wheat were observed in tribenuron-methyl and florasulam + clopyralid, while in the weed-infested treatment, the highest values of both parameters were recorded in late sowing. Finally, the results showed that the sowing date is a cultural weed control method that should be implemented in IWM programs, since it can affect both weed density and herbicide efficacy.

Effect of Pre-and Post-Emergence Herbicides Application on Weed Flora, Yield, and Economics in Kharif Maize (Zea mays L.)

Nowadays labor charges have significantly increased the production cost of maize in India. Hence, to overcome this problem a field experiment entitled “Effect of pre-and post-emergence herbicides on weed flora, yield and economics in Kharif maize (Zea mays L.)” was conducted at Crop Research Center, ITM University, Gwalior during the Kharif season of 2021. The texture of the experimental field was sandy loam, having a pH of 7.6, organic carbon of 0.34, and available N, P2O5, and K2O of 164, 19.6 and 416.7 kg/ha, respectively. The field experiment was laid out in RBD (Randomized Block Design) with nine treatments and three replications. The results showed that among the herbicide treatments a significant reduction in the total weed density and dry matter of different weed flora were recorded with Atrazine 50% WP 1000 g/ha PE fb Topramezone 33.6% SC 25.2 g/ha POE, and found at par with Metribuzin 70% WP 400 g/ha fb Topramezone 33.6% SC 25.2 g/ha. Concerning the yield of maize, Atrazine 50% WP PE fb Topramezone 33.6% SC POE 1000 fb 25.2 g/ha, recorded significantly higher values of grain yield and stover yield of maize, as compared to other herbicide treatments. It may be concluded that Atrazine 50% WP1000 g/ha PE fb Topramezone 33.6% SC 25.2 g/ha POE, recorded highest WCE (91.25%) and superior with respect to grain yield of maize (5365 kg/ha) and economics (Net return Rs. 84377 and BCR Rs. 2.36) over all the weed control treatments.

INFLUENCE OF AGRICULTURAL SYSTEM ON THE CONTROL OF BROMUS TECTORUM ON WINTER WHEAT

Bromus tectorum causes special problems because of its ability to reproduce through seeds and also because it’s relative tolerance to numerous herbicides. Extending new tillage systems, conservative systems specific to conservative sustainable agriculture, is a difficult task to accomplish under the circumstances of strong monocotyledonous weed infested Bromus tectorum is one of the most dangerous monocotyledonous weeds when applying unconventional system. A research was conducted in the pedoclimate condition of Agricultural Research and Development Station Turda, investigating the control of Bromus tectorum by conservative tillage. The goal was to determine the relationship between agricultural system and weeding degree on winter wheat. The use of minimum tillage and no tillage systems, caused at the end of a three year crop rotation, the increase of the Bromus tectorum pervasion in two systems, MD and NT. The occurrence of B. tectorum it is caused mainly due to the fact that the seeds are located in the first cm of the soil. Total weed density was significantly lower under the conventional tillage system (CS) and minim-chisel (MC) than under the minimum tillage-disk (MD) and no till (NT) system. The main benefit of the conventional tillage (CS) is a highly important decline of weeds.

A non‐chemical weed control strategy, introducing duckweed into the paddy field

Herbicide resistance in weeds and environmental pollution resulting from excessive application of chemical herbicides keeps increasing. Development of environment-friendly and effective weed management strategies are required for sustainable agricultural production. In this study we investigated the effects of duckweeds (Landoltia punctata (G. Meyer) Les & D. J. Crawford and Spirodela polyrhiza (Linnaeus) Schle iden) introduction on the weed community and rice growth in paddy fields. The study was conducted in the two rice-growing seasons (2018 and 2019) with three treatments: rice grown without duckweed introduction (CK), with L. punctata introduction (LP), and with S. polyrhiza introduction (SP). On average, LP and SP significantly reduced total weed density by more than 90% and 97%, respectively. Early in the rice-growing season, both duckweed species completely prevented weed growth. Further, both species significantly promoted rice plant growth in the advanced stages. SP significantly improved grain yield of rice by 23%. Light transmittance, temperature of the floodwater and soil, floodwater pH, and dissolved oxygen content significantly decreased following introduction of the duckweeds, indicating that the duckweeds introduction might inhibit weeds growth by altering environmental factors. This study provides a possible environment-friendly way to inhibit weed biomass in the paddy field by introducing duckweeds and interpreted the possible reasons of the impacts of duckweed on environmental variables. Weed control is beneficial for rice growth. Duckweed coverage might be limited in open fields and the associated practice requires additional investigation. This article is protected by copyright. All rights reserved.

Weed Management in Direct Seeded Rice under Different Row Spacing

A field study to evaluate the weed management in direct seeded rice under different row spacing was carried out at Agronomic Research Area, University of Agriculture, Faisalabad during summer 2018. Two herbicides Butachlor @ 118.61 g a.i. ha-1 (pre-emergence) was applied within 24 hours of sowing of direct seeded rice and combination of two herbicides Butachlor @ 118.61 g a.i. ha-1 (pre-emergence) within 24 hours after sowing sequentially followed by Bispyribac Sodium + Bensulfurin Methyl @ 26.7 g a.i. ha-1 + 17.8 g a.i. ha-1 (post-emergence) was applied 15 days after sowing. Bispyribac Sodium @ 26.7 g a.i. ha-1 was applied 15 days after sowing. A weedy check and weed free treatment were also run for comparison. A fine rice cultivar (Basmati 515) was sown during the last week of June in 22.5 cm and 11.25 cm spaced rows using a seed rate of 29 kg ha-1. To fulfill the requirement of nutrients 135 kg N, 88 kg P and 61 kg ha-1 K were applied. The experiment was replicated thrice in a randomized complete block design under split plot arrangement. The net plot size was 3 m × 2.25 m. Date regarding weed density (15, 30 and 45 DAS), weed biomass before harvesting and yield components of rice were recorded by following standard procedures and statistically analyzed by applying Fisher’s analysis of variance technique. Least significant difference test (LSD) at 5% probability was used to compare treatments means. Results of the study showed that total weed density and weed dry weight were significantly influenced by different row spacing and weed control treatments. Significantly lower weed density and weed biomass were observed under narrow row spacing (11.25 cm) as compared to wider row spacing (22.5 cm). Among weed control treatments application of Butachlor @ 118.61 g a.i. ha-1 (pre-emergence) within 24 hrs after sowing of DSR and Bispyribac Sodium @ 26.7 g a.i. ha-1 (15 DAS) reduced the total weed density and weed dry weight. Similarly, paddy yield was also significantly influenced by different row spacing and weed control treatments as weed free at 11.25 cm row spacing gave maximum paddy yield (4.0 t ha-1).

Weed Management Practices on Crop Productivity and Economics in Dry-Direct Seeded Rice under Hill and Plateau Region of Eastern India

In direct seeded rice, weeds are the major problems limiting the crop productivity. Sesbania with direct seeded rice (DSR) as well as seeding rates of rice affects the weed density by smothering effect and therefore, it can be a better weed management practice. Two year on farm trials were conducted at the Kusma, Boarijore Block and Bhaluka, Sundarpahadi block of Godda from 2020 and 2021 to assess the effect of weed management on yields and economics in DSR. The results revealed that significantly the lowest density of grasses, broad leaved weeds (BLWs), sedges, total weed density, total weed dry weight and the highest weed control efficiency were recorded with the treatment of DSR + Sesbania over DSR (pre-sowing irrigation followed by tillage and rice seeding) followed by first post-sowing irrigation at 15 DAS and the farmer’s practice. Weed management practice, DSR + Sesbania was found significantly higher grain yield, gross returns, net returns, B: C ratio, production efficiency and economic efficiency over to followed by first post sowing irrigation at 15 DAS and farmer’s practice. While the farmer’s practice was recorded higher weed index and lowest weed control efficiency. Thus, on the basis present study it is concluded that weed management practice i.e. DSR + Sesbania could be a better option to reduced the weed infestation as well as improves the productivity of DSR in rainfed agro-ecosystem of Jharkhand.

Weed Dynamics and Productivity of French Bean (Phaseolus vulgaris L.) as Influenced by Organic Sources of Nutrients and Weed Management

Background: Balancing productivity, profitability and environmental health is a key challenge for maintaining agricultural sustainability. The use of locally available agro-inputs in agriculture by avoiding or minimizing the use of synthetically compounded agro-chemicals appears to be one of the probable options to sustain the agricultural productivity. Widespread use of herbicides has resulted in purported environmental and health problems as well as residual toxicity issues in succeeding crops. At present, the awareness on safe food is increasing. So, keeping this point in view the present investigation was carried out to evaluate the influence of organic sources of nutrients and weed management on growth, yield and weed flora of Frenchbean. Methods: A field experiment was conducted during summer season of 2016 and 2017. The present investigation was laid out in split plot design with six sources of nutrients in main plot and four weed management treatments in sub plots. Result: Application of treatment T5 recorded significantly higher growth parameters, yield attributes, fresh pod yield, net returns and B:C ratio of French bean which was statistically at par with T3 and T2. Amongst the weed management treatments, treatment W1 resulted in significantly lowest species wise and total weed density and biomass, highest weed control efficiency, lowest weed index, highest growth, yield attributes and fresh pod yield of French bean which was statistically at par with W2 and W0. However, the highest net returns and B:C ratio were obtained in weed free plots.

Response of Rice (Oryza sativa L.) to Weed Management Methods in the Lower Gangetic Plain Zone

Background: In India, rice covers largest area under cultivation. Among the biotic stresses weeds pose serious threat to rice if not controlled in its critical crop-weed competition period, reducing yield by 50%, in case of transplanted rice. The experiment was carried out to evaluate effectiveness of different herbicides and its combination with mechanical weed control methods in checking weed population in transplanted rice so as to maintain sustained production. Methods: The experiment was carried out in lower Gangetic plain zone during kharif season of 2018. It was laid out in randomized block design with seven treatments replicated thrice. The treatments were pretilachlor 50% EC@ 1500 ml ha-1 (0-4 DAT), butachlor 50% EC @ 4000 ml ha-1 (0-4 DAT), bispyribac Na 10% SC @ 200 ml ha-1 (Post-emergence), Sesbania intercrop @ 25 kg ha-1 up to 30 DAT followed by mechanical incorporation followed by 1 hand weeding @ 50 DAT, pretilachlor 50% EC @ 1500 ml ha-1 (0-4 DAT) followed by bispyribac Na 10% SC @ 2000 ml ha-1 (25 DAT), two hand weedings at 25 DAT and 50 DAT and untreated control. Result: Cyperus rotundus, Cyperus difformis, Alternanthera philoxeroides, Ludwigia octovalvis, Echinochloa colona, Fimbristyslis sp. were the dominating weed species as per experimental findings. Among all treatments two hand weedings at 25 DAT and 50 DAT significantly reduced the total weed density (no.m-2) while total weed biomass (g m-2) as was found to be lowest in treatment of pretilachlor 50% EC @ 1500 ml ha-1 (0-4 DAT) followed by bispyribac Na 10% SC @ 2000 ml ha-1 (25 DAT). Highest growth characteristics in rice was observed in treatment of two hand weedings at 25 DAT and 50 DAT. Pre- emergence and post-emergence application of pretilachlor and bispyribac sodium, respectively, was successful in achieving highest yield attributes, yield (4.12 t ha-1) and economic return (Rs. 47438 ha-1).

Evaluation of Combined Weed Control Practices on Weed Dynamics, Yield and Economic Return in Common Bean (Phaseolus vulgaris L.) at Wolaita Sodo, Southern Ethiopia

The field experiment was conducted in Wolaita Zone, Southern Ethiopia, to evaluate different weed management practices on weed dynamics, yield and economic return in common bean in 2014. The experiment comprised of fifteen treatments which included two herbicides (s-metolachlor and pendimethalin) applied as pre-emergence alone and in different combinations, hand weeding and hoeing, weedy check all with and without mulching and weed free check laid out in randomized block design with three replications. The application of pendimethalin 1.0 kg ha -1 + mulching at 2 weeks after crop emergence (WAE) resulted in significant decrease in total weed density over weedy. Weed dry weight varied in response to weed significantly management practices at 2 WAE. However, at 12 WAE this has no significant difference with pendimethalin 1.0 kg ha -1 + hand weeding and hoeing 5 WAE, s-metolachlor 0.75 kg ha -1 + pendimethalin 0.75 kg ha -1 + mulching and hand weeding and hoeing at 2 and 5 WAE. At 12 WAE, the highest weed control efficiency (99.8%) was obtained with hand weeding and hoeing at 2 and 5 WAE which is statistically at parity with pendimethalin 1.00 kg/ha+ hand weeding and hoeing 5 WAE (99.4%. Weed infestation throughout the growing period suppressed the plant height by about 29.6 to 95.3% compared to other treatments. The highest number of pods per plant was recorded under complete weed free and it was statistically in parity with pendimethalin at 1.0 kg ha -1 + hand weeding and hoeing 5 WAE. Weedy check resulted in significant decrease in number of pods per plant which varied between 28.6 and 54.4% over other treatments. The highest number of seeds/pod was also obtained with complete weed free plots but in addition to pendimethalin at 1.0 kg ha -1 + hand weeding and hoeing 5 WAE, Weight of hundred seeds was maximum with complete weed free which was statistically in parity with the application of pendimethalin at 1.0 kg ha-1 + hand weeding and hoeing at 5 WAE and two hand weeding and hoeing 2 and 5 weeks after crop emergence (WAE) treatments. Highest grain yield (1982 kg ha -1 ) and net returns (ETB 17362 ha -1 ) was obtained with the application of pendimethalin 1.0 kg ha -1 + hand weeding and hoeing 5 weeks after crop emergence. Generally, it could be concluded that pendimethalin 1.0 kg ha-1 combined with one hand weeding and hoeing at 5 WAE was the most appropriate method for effective weed management and profitable production of common bean. Keywords: Herbicides combination, mulch, pendimethalin, pre-emergence, s-metolachlor, yield, economic feasibility DOI: 10.7176/JBAH/12-6-01 Publication date: March 31 st 2022

Evaluation of Sulfentrazone Alone or in Combination with Other PRE and POST Herbicides for Weed Control in Tomato (Solanum lycopersicum) and Strawberry (Fragaria ×ananassa)

Sulfentrazone was recently registered for use in tomato and strawberry in Florida. Field experiments were conducted at the Gulf Coast Research and Education Center in Wimauma, FL, to evaluate PRE sulfentrazone applications when applied on flat soil 30 days before bed formation (PRE-f), on the bed top immediately before laying plastic mulch (PRE-t), applied PRE-t as a tank mix with other PRE herbicides, or PRE-t followed by POST halosulfuron or rimusulfuron (POST). Sulfentrazone did not damage the tomato and strawberry crop and had no effect on strawberry and tomato fruit yield. It was as effective as the industry standards but none of the evaluated herbicide treatments provided adequate weed control. POST halosulfuron in tomato resulted in significantly greater nutsedge control at 11 (14%) and 13 (27%) weeks after initial treatment (WAIT) compared with other treatments in Fall 2019 and Spring 2020, respectively. However, in tomato, tank-mixing sulfentrazone with S-metolachlor or metribuzin did not enhance nutsedge control. Weed control did not improve with increased rates or with the use of PRE-f followed by (fb) PRE-t applications in tomato. PRE-t sulfentrazone fb POST halosulfuron was an efficient nutsedge management option in tomato. Sulfentrazone alone did not effectively control weeds in tomato or strawberry. Increased rates of sulfentrazone with the use of PRE-f fb PRE-t sulfentrazone applications did reduce (34%) total weed density in strawberry.

Fall-Planted Cover Crops for Weed Suppression in Western Kansas

The widespread evolution of herbicide-resistant (HR) kochia and Palmer amaranth warrants the use of alternative ecological-based strategies for weed management in no-tillage (NT) dryland cropping systems in western Kansas. A field study was established in the fall of 2020 at Kansas State University Agricultural Research Center near Hays, KS, to determine the impact of fall-planted cover crop (CC) mixture on 1) kochia and Palmer amaranth suppression (density and biomass reduction), and 2) Palmer amaranth emergence dynamics in subsequent grain sorghum. A CC mixture of winter triticale, winter pea, radish, and rapeseed was planted in wheat stubble in the fall of 2020. The CC mixture was terminated at triticale heading stage on May 26, 2021 by using 1) Roundup PowerMax (glyphosate) at 32 fl oz/a, and 2) Roundup PowerMax at 32 fl oz/a + Degree Xtra (premix of acetochlor + atrazine) at 2.2 quart/a. A chemical fallow treatment (without CC) was included for comparison. The study site was planted with grain sorghum hybrid ‘DKS 38-16’ on June 10, 2021. The CC mixture produced an average of 1360 lb/a aboveground biomass at the time of termination. The CC terminated with Roundup PowerMax + Degree Xtra had 98 and 95% less total weed density at 0 and 30 days after termination (DAT), respectively, compared to chemical fallow. No difference in weed density was observed at later evaluations. At grain sorghum harvest, CC terminated with Roundup PowerMax and Roundup PowerMax + Degree Xtra reduced total weed biomass by 61% and 73%, respectively, compared to chemical fallow. The time taken to reach 10, 50, and 90% cumulative emergence of Palmer amaranth was delayed by 9, 15, and 21 days, respectively, in CC terminated with Roundup PowerMax and 11, 39, and 128 days, respectively, in CC terminated with Roundup PowerMax + Degree Xtra when compared with chemical fallow. Grain sorghum yield did not differ between CC and chemical fallow treatments. These results suggest that a fall-planted CC mixture can play an important role for kochia and Palmer amaranth suppression in NT dryland crop production in western Kansas.

Effect of different pre- and post-emergence herbicides for weed management in chickpea

A field experiment was conducted during the winter (Rabi) season 2017-18 at Instructional Agronomy Farm of Rajasthan College of Agriculture, MPUAT, Udaipur. The experiment consisted of twelve weed management treatments which were replicated thrice in Randomize Block Design. Chickpea (cv. Pratap Chana-1) was used as a test crop. The hand weeding twice 30 and 60 days after seeding (DAS) followed by pre-emergence application (PE) of pendimethalin 1000 g/ha or pendimethalin 750 g/ha have significantly reduced total weed density and biomass and attained the highest chickpea seed yield. The net return and B:C ratio was significantly higher with pendimethalin 1000 g/ha PE and pendimethalin 750 g/ha PE due to lesser cost of herbicides usage compared to hand weeding.

Integration effect of drip irrigation and mulching on weeds and spring maize productivity

A field experiment was carried out at Research Farm, Department of Agronomy, Punjab Agricultural University, Ludhiana during spring season of 2020 and 2021. The experimental design was split-plot with three replications. The main plots included the combination of two methods of drip irrigation, viz. surface drip irrigation (SD) and sub-surface drip irrigation (SSD) and three mulch treatments, viz. plastic mulch (PM), straw mulch 6 t/ha (SM) and no mulch (NM) along with furrow irrigation (FI) as a control treatment. The sub-plots consisted of four weed control treatments, viz. pre- emergence application (PE) of atrazine 1000 g/ha, hand weeding twice at 30 and 60 days after seeding (DAS), weed free and weedy check. The dominant weed species were Cyperus rotundus, Oenothera laciniata, Chenopodium album, Coronopus didymus, Rumex dentatus, Digitaria sanguinalis, and Dactyloctenium aegyptium. The maize emergence was 6 days earlier under plastic mulch than the crop under straw mulch. The SD-PM, SD-SM, SSD-PM, SSD-SM and SSD- NM resulted in maximum maize plant height when compared to FI. SD-PM, SD-SM, SSD-PM and SSD-SM treatments recorded significantly lower total weed density and biomass at 30 DAS than the atrazine treated FI treatment. Maximum weed control efficiency of 88.89% was recorded under integration of drip irrigation with plastic mulch. Integration of drip irrigation and mulches resulted in significantly increased maize grain yield as compared to FI. Crop raised under SD- SM treatment resulted in 20.62% higher grain yield than FI. The integration of drip irrigation with mulching resulted in effective weed management and higher maize grain yield than furrow irrigation method.