Residual Effect Of Herbicides Research Articles

Oxyfluorfen and Linuron: Residual Effect of Pre-Emergence Herbicides in Three Tropical Soils

Knowledge about the residual effect of herbicides is important in order to increase agronomic efficacy and reduce environmental problems. Therefore, the objective of this study was to evaluate the residual effect of oxyfluorfen and linuron in three soils. Pots of 0.35 dm3 were filled with three Brazilian soils: Ultisol, Oxisol, and Inceptisol. Then, the herbicides were applied at different times at 0, 15, 30, 45, 60, 90, 120, 150, 180, and 200 days and the bioindicator species of linuron and oxyfluorfen were sown. Then, the injury was evaluated at 7, 14, and 21 days after emergence (DAE) to find the half-life of the herbicide residue level (RL50) and the dose of herbicide that provides a 50% reduction in dry matter (GR50). In the soil with oxyfluorfen application, the RL50 at 21 DAE was 59, 57, and 51 days and GR50 was 49, 47, and 31 days for Ultisol, Oxisol, and Inceptisol, respectively. Soils with linuron application had RL50 of 75, 92, and 149 days and GR50 of 52, 48, and 120 days for Ultisol, Oxisol, and Inceptisol, respectively. The higher organic matter and clay content of Ultisol compared to Oxisol and Inceptisol resulted in a lower residual effect of linuron. There was little difference between soil type and the residual effect of oxyfluorfen, which may be related to the physicochemical characteristics of the molecule.

Residual herbicides affect critical time of Palmer amaranth removal in soybean

AbstractGlyphosate‐resistant (GR) Palmer amaranth (Amaranthus palmeri S. Watson) is one of the most difficult to control weeds in soybean [Glycine max (L.) Merr.] production fields. Residual pre‐emergence (PRE) herbicide applied at planting is one of the recommendations for management of herbicide‐resistant Palmer amaranth; however, information is not available about the effect of residual herbicides on critical time of Palmer amaranth removal (CTPAR) to prevent an unacceptable yield loss in soybean. The objective of this study was to determine the CTPAR in soybean affected by residual PRE herbicides compared with the no PRE herbicide in southcentral Nebraska. Field experiments were conducted in 2018 and 2019 in a grower's field infested with GR Palmer amaranth near Carleton, NE. The treatments were arranged in a split‐plot design with PRE herbicides (no PRE herbicide, flumioxazin, and a premix of flumioxazin/metribuzin/pyroxasulfone) as the main plot and Palmer amaranth removal timings as subplot treatments (a weed‐free control; a nontreated control; and Palmer amaranth removal timing at the V1, V3, V6, R2, and R5 soybean growth stages). In the absence of a PRE herbicide, the CTPAR at 5% soybean yield loss occurred at V1 and V6 soybean growth stages, equivalent to 194 and 480 Celsius growing degrees days (GDDc) in 2018 and 2019, respectively. When flumioxazin was applied alone, the CTPAR was delayed until the V3 and V6 soybean growth stages, or 341 and 501 GDDc. When flumioxazin/metribuzin/pyroxasulfone premix was applied, the CTPAR was delayed until the V2 and R1 soybean growth stages, corresponding to 255 and 546 GDDc, in 2018 and 2019, respectively.

Production of Fenugreek (Trigonella foenum-graecum) as Influenced by Weed Management Practices and Vermicompost Application

Background: A field experiment was conducted at the Instructional Farm of Rajasthan College of Agriculture, Maharana Pratap University of Agriculture and Technology, Udaipur during Rabi 2016-17 and 2017-18 to study the weed flora, growth, yield and economics of fenugreek. The experiment was laid out in split plot design with three replications having Fenugreek variety RMT-305 (25 kg ha-1) and RDF of 40 kg N and 40 kg P2O5 ha-1 (basal dose through urea and DAP). Methods: Herbicide applied as pre-emergence (PE) at one day after sowing, while post-emergence (PoE) application at 2-4 leaf stage of weeds (21 DAS) with knapsack sprayer having flat fan nozzle using 500 liters of water ha-1. Result: The pooled results revealed that pre-emergence application of oxadiargyl 100 g/ha fb hoeing at 40 DAS recorded significantly higher weed control efficiency (82.3%), plant height (59.83 cm), number of branches (6.09), number of pods (44.86), number of seeds/pod (17.33), seed weight (9.05 g/plant) of fenugreek. Also, significantly maximum seed yield (2.82 t/ha), haulm yield (6.70 t/ha) and harvest index (29.7%) of fenugreek was recorded under oxadiargyl 100 g/ha PE fb hoeing at 40 DAS which was at par with weed free treatment. Significantly higher net returns (98158 `/ha) and B C ratio (2.63) was obtained with application of oxadiargyl 100 g/ha Pre-Emergence (PE) fb hoeing at 40 DAS. Residual effect of herbicides used in fenugreek did not showed any phytotoxic effect on succeeding summer fodder maize in terms of visual phytotoxicity rating at various growth stages of maize, weed flora, dry matter of weeds as well as crop at 30 DAS and green fodder yield of summer fodder maize.

Residual Effect of Herbicides Used in Pastures on Clover Establishment and Productivity

A major hindrance to establishment of successful complementary forage systems that include warm-season perennial grasses and clovers is tolerance of the latter to herbicides available for weed control. Field experiments were conducted in 2013 at two locations in northeast Louisiana to evaluate simulated residual rate effects of fluroxypyr plus triclopyr and 2,4-D plus picloram applied at 0, 0.25, 0.38, and 0.5× use rates immediately after fall planting of ball, white, crimson, and red clover. For all clovers, when averaged across herbicide rates, plant population 161/171 d after planting (DAP), ground cover, and height 184/196 DAP were equivalent for fluroxypyr plus triclopyr and the nontreated control and greater than 2,4-D plus picloram. Averaged across clovers, plant height after all rates of fluroxypyr plus triclopyr was equivalent to the nontreated control (14.2 to 14.3 vs. 15.3 cm) and greater than 2,4-D plus picloram. Compared with the nontreated control, 2,4-D plus picloram at 25, 38, and 50% of the normal use rates reduced height 58, 76, and 85%, respectively. When averaged across clover species, yield for fluroxypyr plus triclopyr at all rates was equivalent to the nontreated control (2,624 to 2,840 vs. 2,812 kg ha−1). Compared with the nontreated control, 2,4-D plus picloram at the 0.25, 0.38, and 0.50× use rates reduced yield 65, 89, and 99%, respectively.

Carryover de herbicidas em sistemas cultivados com olerícolas

O efeito residual de herbicidas no solo sobre culturas sucessoras sensíveis é conhecido como carryover. A maioria dos estudos sobre carryover em olerícolas tem sido desenvolvida em outros países, no entanto, os problemas advindos desse fenômeno são uma realidade também no Brasil. A limitada informação presente na literatura, aliada à ausência de alertas e períodos de restrição nas bulas dos herbicidas comercializados no país para o cultivo de olerícolas sensíveis em sucessão contribuem para a ocorrência de grandes prejuízos aos olericultores. Carryover de herbicidas pode causar intoxicação de forma visível ou não nas olerícolas, reduzir o crescimento e a produtividade, assim como comprometer a qualidade do produto e até mesmo inviabilizar a área para o cultivo por anos. A presente revisão descreve a dinâmica dos herbicidas no solo e reúne diversos trabalhos acerca do efeito residual de herbicidas em olerícolas. Além disso, discute as possíveis formas de monitoramento das áreas cultivadas, através da análise em laboratórios ou de bioensaios, e as estratégias para minimizar os efeitos danosos nessas culturas, que são altamente sensíveis. Nesse contexto, o manejo integrado de plantas daninhas é essencial para redução da necessidade de utilização de herbicidas e aporte desses no solo, diminuindo os riscos de carryover, além de medida legislativa para inclusão dos períodos de restrição de cultivo de olerícolas sensíveis nas bulas dos herbicidas.

Direct and residual effect of herbicides on weed dynamics and productivity of soybean (Glycine max) -wheat (Triticum aestivum) cropping system

A field experiment aimed to evaluate the bio-efficacy of new low dose herbicides applied in soybean and their residual effect on succeeding wheat was conducted during 2007-08 and 2008-09 at New Delhi. Results revealed that in soybean, post-emergence application of imazethapyr (100 g/ha) was more effective against Trianthema portulacastrum, Commelina benghalensis, Digitaria sanguinalis and Dactyloctenium aegyptium but pendimethalin (1500 g/ha) against Dactyloctenium aegyptium, Digitaria sanguinalis and Trianthema portulacastrum. Chlorimuron-ethyl provided effective control of broad-leaved weeds but failed to control grasses and sedges. Application of imazethapyr (100 g/ha) increased the seed yield of soybean by 66.49% over weedy check. Herbicidal application significantly suppressed the microbial population at 30 DAS which recovered at the harvest of soybean. The residual effect of chlorimuron-ethyl (6-12 g/ha) and imazethapyr (50-100 g/ha) applied in soybean resulted in significant reduction in population of all major weeds except Avena ludoviciana in wheat grown in rotation. No injury to wheat plant was observed due to residues of chlorimuron-ethyl (6-12 g/ha) and imazethapyr (50-100 g/ha) and other herbicides applied in soybean.

Sistemas de manejo de plantas daninhas na pré-semeadura da soja

The study aimed to evaluate the efficiency and residual effect of herbicides, applied in management operations, in modalities “Apply-Plant” and “Anticipated Management” in soybean crop. The experimental design was randomized complete blocks with four repetitions in 8 x 2 factorial scheme, with eight herbicides associations (with flumioxazin, chlorimuron-ethyl and glyphosate) in two management systems. For “Anticipated Management” was conducted glyphosate application 20 days before sowing, with treatments being applied two days after planting. For “Apply-Plant” system, treatments were applied one day before crop sowing. It was evaluated the control efficiency and residual effect of herbicides over Euphorbia heterophylla , Amaranthus hybridus e Commelina benghalensis , besides plant height, stand and soybean yield. Results showed that “Anticipated Management” proportionate better weeds control than “Apply-Plant”, besides ensuring that soybean crop could be able to develop under better conditions, thus guaranteeing greater yield. Flumioxazin and chlorimuron presence was enough to ensure the closing canopy of crop without a post-emergency application.

Effect Of Residual Herbicides Used in the Last Post-directed Application on Weed Control and Cotton Yield in Glyphosate- and Glufosinate-resistant Cotton

Field experiments were conducted to evaluate weed control and cotton response to glyphosate or glufosinate applied alone or with residual herbicides applied in the last POST-directed application (LAYBY) in glyphosate- and glufosinate-resistant cotton. Glyphosate (0.86 kg ae/ha) or glufosinate (0.47 kg ai/ha) were applied alone over the top of glyphosate- or glufosinate-resistant cotton early POST (EPOST) followed by (fb) late POST (LPOST) fb one of the herbicides applied either alone or with a residual herbicide at LAYBY. Glyphosate- and glufosinate-based treatments were applied only to glyphosate- and glufosinate-resistant cotton, respectively. Residual herbicides evaluated included prometryn (1.12 kg ai/ha), fluometuron (1.12 kg ai/ha), diuron (1.12 kg ai/ha), oxyfluorfen (1.12 kg ai/ha), pendimethalin (1.0 kg ai/ha), prometryn + trifloxysulfuron (1.33 kg ai/ha + 12 g ai/ha), or linuron + diuron (0.56 + 0.56 kg ai/ha). Glyphosate-and glufosinate-based weed management systems with and without residual LA...

Effect of Time of Application and Residual Effect of Herbicides in Direct Seeded Flooded and Rainfed Bunded Rice

Effect of Time of Application and Residual Effect of Herbicides in Direct Seeded Flooded and Rainfed Bunded Rice