Recommended Dose Of Herbicide Research Articles

Relative Benefits of Aqueous Extract of Sorghum Residues with Herbicide on Weed Control and Yield of Wheat Varieties

Reducing herbicide use in agriculture is key for sustainability, addressing costs, environmental issues, and resistance problems. Using non-chemical methods like allelopathy in weed management offers a viable alternative. In this phenomenon, a field study was carried out at the Agronomy Field Laboratory (AFL) of Bangladesh Agricultural University (BAU), Mymensingh, from November 2021 to March 2022, to assess the phytotoxic effects of herbicides combined with aqueous extract of sorghum (AES) on weed management and yield of wheat. This study used three wheat varieties viz. BARI Gom (wheat)-32, BARI Gom-33, and BWMRI Gom-1 and six treatment levels such as, no weeding, recommended dose of herbicide (RDH), 90% RDH + AES (1:20 w/v), 80% RDH + AES (1:20), 70% RDH + AES (1:20), and 60% RDH + AES (1:20). The experiment followed a randomized complete block design (RCBD) with three replications. The RDH with AES and wheat variety significantly influenced weed population (WP) and dry weight (DW) of weeds. BARI Gom-32 produced the highest grain yield (GY) and other yield-contributing characteristics. The best results, including the highest numbers of tillers (NET) hill-1 (6.47), spike length (SL) (15.10 cm), number of spikelet spike-1 (NSS) (19.38), 1000-grain weight (TGW) (57.67g), GY (5.10 t ha-1), and straw yield (SY) (7.07 t ha-1) and harvest index (HI) (41.95%) were observed in plots treated with the RDH and the BARI Gom-32 variety, followed closely by those receiving 90% RDH + AES (1:20). The results demonstrate that varying concentrations of AES crop residue can effectively suppress weed growth and enhance wheat yield, suggesting that sorghum residues might be utilized to manage weeds effectively and sustainably while boosting wheat production. The study supports the potential of AES crop residue as an effective means to control weeds and significantly improve wheat yields. J Bangladesh Agril Univ 22(3): 326-334, 2024

The Effect of Tillage Systems and Weed Control Methods on Grain Yield and Gluten Protein Compositional and Content-Related Changes in Hybrid Bread Wheat

The use of simplified tillage systems and weed control methods using reduced herbicide doses in wheat production technology is one of the basic requirements of sustainable agriculture in terms of obtaining high-quality grain of this species. The aim of three-year field studies was to determine the yield and quality characteristics of hybrid wheat grain depending on two tillage systems (CT and RT) and four weed control methods: mechanical (M) and mechanical–chemical, using recommended herbicide doses (MH100) and doses reduced by 25 and 50% (MH75, MH50). A comparable grain yield, number of grains per spike, weight of one thousand wheat grains, and amount of gluten and ω gliadin subunits (GLI) were obtained in the RT and CT systems. The CT system increased protein content (by 15.2 g kg−1) and the increase in the sum of gluten protein fractions was higher for glutenins (GLU) and their LMW and HMW subunits (from 20.9 to 29.8%). The application of the method with the recommended herbicide dose (MH100), compared to M and MH50, resulted in an increase in grain yield by 0.89 and 1.04 t ha−1, respectively, as well as in the sum of GLI (by 8.4 and 12.3%) and GLU (by 13.7 and 25.3%). The application of the herbicide dose reduced by 25% (MH75) compared to the recommended dose (MH100), especially in the RT system, did not cause a significant decrease in protein content and the amount of GLI and GLU, while reducing grain yield (by 0.26 t ha−1) and the amount of gluten (by 3.1%).

Combined Application of Herbicide and Aqueous Extract of Sorghum and Mustard Crop Residue Enhance Weed Management and Yield of Wheat

The rising costs in agriculture and growing public concern over herbicide use have emphasized the need for non-chemical weed control methods. To evaluate the impact of aqueous extracts from sorghum and mustard crop residues on weed control and wheat crop performance, an experiment was conducted at the Agronomy Field Laboratory (AFL) of Bangladesh Agricultural University (BAU), Mymensingh, from November, 2021, to March 2022. The study involved three wheat varieties (BARI Gom-32, BARI Gom-33, and BWMRI Gom-1) and six treatment levels: no weeding, the recommended dose of herbicide (RDH), 80% RDH + aqueous extract of mustard + sorghum (AEMS) (1:20 ratio w/v), 70% RDH + AEMS (1:20), 60% RDH + AEMS (1:20), and 50% RDH + AEMS (1:20). The experiment was designed using a randomized complete block design with three replications. Results demonstrated that the aqueous extracts significantly reduced weed population (WP) and dry weight (DW) of weeds. Among the wheat varieties, BARI Gom-32 achieved the highest grain yield (GY) (3.62 t ha-1) and other yield-contributing traits. The highest numbers of effective tillers (NET) per hill (4.56), numbers of grains per spike (NGS) (34.57), 1000 grain weight (TGW) (57.81 g), GY (4.09 t ha-1), straw yield (SY) (6.05 t ha-1), and biological yield (BY) (10.14 t ha-1) were observed in the RDH treatment, followed by the combined application of 80% RDH and AEMS crop residue (1:20). These findings suggest that AEMS crop residue extracts could be an effective source for suppressing weed population and enhancing yield.

Compatibility studies of indigenous Trichoderma isolates with pesticides

A total of 40 Trichoderma isolates collected from North-Eastern dry zone of Karnataka. Isolates were identified at species level by sequencing of tef1 gene. The gene sequencing results revealed that T. asperellum and Hypocrea lixii were predominantly distributed throughout the surveyed area. Among the isolates sequenced, 27 represents as T. asperellum and nine as Hypocrea lixii, two as T. harzianum and each one as T. afroharzianum and T. asperelloides. Trichoderma isolates expressed the pertinent compatibility with pesticides tested, Carbendazim and Hexaconazole fungicides were not compatible at any given concentration with the isolates. However, maximum compatibility was found in T-45, T-2, T-9 and T-16 isolates against Mancozeb at 0.15 and 0.20 per cent. The recommended dose (RD) of Chlorpyrifos (0.15 %), Imidacloprid (0.03 %) and Acephate (0.1 %) insecticide was found highly compatible with all the isolates. The RD of herbicide 2, 4-D and Glyphosate are more compatible than the Pendimethalin. Among the agrochemicals tested Mancozeb; Chlorpyrifos; Imidacloprid; Acephate; 2, 4-D and Glyphosate are compatible with Trichoderma isolates. The T-45, T-42, T-39 and T-43 isolates were identified as best pesticide tolerant isolates. Incorporation of pesticide tolerant Trichoderma strains in integrated diseases management (IDM) provides added advantages in many perspectives.

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 herbicides and doses on short‐ and long‐term control of Eleusine tristachya

AbstractIn Argentina, Eleusine tristachya has been recently reported as a problematic weed that can occur at high densities in spring and summer in fallows and in maize and soyabean. The reason for the increase in E. tristachya populations is that once the weed is established, it is difficult to eliminate because it produces a high number of seeds and plant regrowth occurs after herbicide treatments. The aim of this study was to determine the effect of post‐emergence application of herbicides (glyphosate, haloxyfop‐methyl and clethodim) at the seedling, vegetative and reproductive stages on the short‐term (biomass 30 days after treatment—30 DAT) and long‐term (tiller number and height and seed production—regrowth at 330 DAT) control of E. tristachya selected biotypes in outdoor pot experiments. Data fitted to a log‐logistic model. For all the herbicides considered, at the seedling and vegetative stages, short‐term control was achieved with low ED50 and ED90 values, whereas at the reproductive stage, ED90 values were three‐ to sixfold (glyphosate), six‐ to 52‐fold (haloxyfop‐methyl) and five‐ to 13‐fold (clethodim) higher. Long‐term control at the recommended dose or lower was not possible at the reproductive stage as tiller regrowth and seed production occurred with all herbicides. It is advisable to control Eleusine tristachya when plants are small at the beginning of the growing season using the recommended herbicide dose. A delayed application will produce tiller regeneration the following year, and consequently, control would only be achieved applying an overdose, which can cause risks to health and the environment. We concluded that a management programme based on the combination of glyphosate with post‐emergence graminicides applied at early stages will be effective to control future infestations.

Efficacy of Glyphosate in Water Management and the Effects on Water Quality

The present work aimed to evaluate the behavior of glyphosate herbicide in aquatic environment, considering some water quality parameters, in reservoir conditions without flow and without replacement of evapotranspired water. Twenty reservoirs (polyethylene water tanks) with a storage capacity of 1000 liters were used. The recommended herbicide dose according to the manufacturer was 7.0 L or 3360 grams of acid equivalent per hectare. For application in the reservoirs, a precision equipment was used to carbon dioxide (CO2), providing a flow of 200 L·ha-1. Freezing macrophyte death was achieved by storing the plants in a freezer at -18°C for a period of 48 hours. The analyses of control efficiency were performed at 7, 14, 21, 28, 35 and 42 days after application (DAA). Water samples for analysis of quality indicators, pH and dissolved oxygen were collected weekly for nine weeks. The obtained result allows concluding that the herbicide glyphosate presented excellent control efficiency of water hyacinth and did not significantly alter the water quality parameters pH and dissolved oxygen, indicating its use in the management of this macrophyte.

Combination of Herbicide Band Application and Inter-Row Cultivation Provides Sustainable Weed Control in Maize

Herbicides have facilitated weed management but their incorrect use can lead to environmental contamination. Reducing herbicide use by limiting their application to a band along the crop row can decrease their environmental impact. Three field experiments were conducted in North-eastern Italy to evaluate herbicide band application systems integrated with inter-row hoeing for silage maize. Post-emergence herbicide band application (sprayed area 50% of total field; herbicide dose 50% of that recommended, application with an inter-row cultivator prototype) was compared with pre-emergence band application (sprayed area 33% of total field; herbicide dose 33% of that recommended, application with a seeder) and pre-emergence broadcast application (sprayed area 100% of total field; full recommended herbicide dose, application with a boom sprayer) that is standard management for maize. Weed density and composition were evaluated before and after post-emergence herbicide application and at crop harvest. Crop yield was also recorded. Weed density in untreated areas ranged between 5 and 15 plants m−2 in the different experiments. Optimal weed control and good yields were achieved without significant differences between all treatments. Herbicide band application can provide optimal weed control in silage maize, at the same time allowing a relevant reduction of herbicide input.

Effect of Soil Fumigation on Degradation of Pendimethalin and Oxyfluorfen in Laboratory and Ginger Field Studies.

Herbicides are usually applied to agricultural fields following soil fumigation to provide effective weed control in high-value cash crops. However, phytotoxicity has been observed in ginger seedlings following the application of herbicides in fumigated fields. This study tested a mixture of herbicides (pendimethalin and oxyfluorfen) and several fumigant treatments in laboratory and field studies to determine their effect on the growth of ginger. The results showed that soil fumigation significantly (P < 0.05) extended the degradation period of these herbicides in the field and in laboratory studies. The half-life of pendimethalin was extended by an average of approximately 1.29 times in the field and 1.74 times in the laboratory. The half-life of oxyfluorfen was extended by an average of about 1.19 times in the field and 1.32 times in the laboratory. Moreover, the extended period of herbicide degradation in the fumigant and nonfumigant treatments significantly reduced ginger plant height, leaf number, stem diameter, and the chlorophyll content. The study concluded that applying a dose below the recommended rate of these herbicides in chloropicrin (CP) or CP + 1,3-dichloropropene fumigated ginger fields is appropriate, as application of the recommended herbicide dose in fumigated soil may be phytotoxic to ginger.

Effects of different cropping systems and weed management methods on free energy and content of pigments in maize

Rotation is a cropping system that has many advantages and ensures better crop growth and yielding. Its combinination with other cropping measures can ensure optimal crop density for maximal growth and photosynthesis efficiency. The aim of this study was to investigate the influence of different cropping systems: monoculture and two rotations, including maize, wheat and soybean (MSW and MWS), and different weed management methods (weed removal by hoeing, application of a full recommended herbicide dose (RD) and half that dose (0.5 RD), and weedy check) on weed biomass and maize growth parameters - leaf area index (LAI), free energy, contents of chlorophyll and carotenoids, grain yield, and their possible relationships in two fields of the maize hybrids ZP 677 (H1) and ZP 606 (H2). The lowest LAI and grain yield were found in monoculture, particularly in weedy check, which had relatively high weed infestation. Higher weed biomass was also observed in herbicide treated plots in monoculture. Such high competition pressure indicates a stress reflected on reduced LAI and chlorophyll content, and increased free energy and content of carotenoids. On the other hand, rotation, particularly if it is combined with the application of herbicides or hoeing, had a positive impact on yielding potential by increasing LAI and the contents of chlorophyll and carotenoids, and decreasing free energy.

Response of imidazolinone‐tolerant and ‐susceptible volunteer oilseed rape (Brassica napus L.) to ALS inhibitors and alternative herbicides

Imidazolinone-tolerant oilseed rape (Brassica napus L.) varieties are currently grown in Canada, North America, Chile and Australia with high acreage. A Europe-wide introduction has started and will be pushed further for both spring and winter varieties. The primary aim of this study was to evaluate the impact of imidazolinone tolerance for future volunteer oilseed rape control in subsequent crops, particularly winter wheat. A greenhouse bioassay showed cross-tolerance of imidazolinone-tolerant oilseed rape towards sulfonylureas, triazolopyrimidines and sulfonylaminocarbonyltriazolinones (resistance factors between 5 and 775), with a homozygous variety expressing a much higher tolerance level compared with a heterozygous variety. Calculated ED90 values suitable for controlling tolerant plants were always much higher than the recommended herbicide dose. Generally, results were confirmed under field conditions, but with higher efficacies than expected in some cases (e.g. florasulam). Herbicides with an alternative mode of action were found to be effective in controlling imidazolinone-tolerant volunteers in subsequent winter wheat crops. Herbicide strategies have to be adjusted for volunteer control in subsequent crops if imidazolinone-tolerant oilseed rape varieties are to be grown. However, agronomic tools (harvest date, harvest technique, tillage) should be used conscientiously in the first place to keep volunteer oilseed rape densities at the lowest possible level.

Naturally occurring phytotoxins in allelopathic plants help reduce herbicide dose in wheat

Field studies were carried out to evaluate the influence of allelopathic plant water extracts applied alone or tank-mixed with a reduced herbicide dose on the weeds of wheat. Water extracts of sorghum (Sorghum bicolor (L.) Moench.) + sunflower (Helianthus annuus L.) + mulberry (Morus alba L.) were used alone (each at 20 L ha–1) or combined with iodo + mesosulfuron (3.6 and 7.2 g active ingredient (a.i.) ha–1; 25 and 50% of the recommended dose, respectively). The recommended dose of herbicide, a weedy check and a weed-free treatment were included for comparison. Allelopathic water extracts alone suppressed the density of canary grass (Phalaris minor Retz.) and wild oat (Avena fatua L.) by 34–42%, and dry weight by 59–67%. The mixture of allelopathic plant water extracts combined with reduced doses of iodo + mesosulfuron gave weed control equal to the recommended dose of the herbicide. Integration of plant water extracts with reduced herbicide rates provide effective weed control and a wheat yield comparable to using the recommended herbicide dose.

Degradation and Leaching of Chlorsulfuron in Three Different Soils

Abstract Degradation and leaching of chlorsulfuron were investigated by radiometric and mass spectrometric methods in three different soils: very heavy clay, medium fine sand and organic soil at 10–11°C. The recommended herbicide dose of 4 g a.i./ha was used. After 4.5 months incubation time in an air-flow-through incubator none of the herbicide in the limed or unlimed test soils was degraded to CO2. However, decomposition of the triazine ring in the molecule had begun. Chlorsulfuron added to 42 cm depth soil columns had began to leach through the whole column containing the sandy soil and to depth of 24 cm in the organic soil after a precipitation of 411 mm over 1.5 months. In the clay soil the herbicide leached to 12 cm of soil depth after precipitation of 121 mm over the same period.