Influence of Application Timings and Sublethal Rates of Synthetic Auxin Herbicides on Soybean

2014 ◽  
Vol 28 (3) ◽  
pp. 454-464 ◽  
Author(s):  
Craig B. Solomon ◽  
Kevin W. Bradley

Synthetic auxin herbicides have long been utilized for the selective control of broadleaf weeds in a variety of crop and noncrop environments. Recently, two agrochemical companies have begun to develop soybean with resistance to 2,4-D and dicamba which might lead to an increase in the application of these herbicides in soybean production areas in the near future. Additionally, little research has been published pertaining to the effects of a newly-discovered synthetic auxin herbicide, aminocyclopyrachlor, on soybean phytotoxicity. Two field trials were conducted in 2011 and 2012 to evaluate the effects of sublethal rates of 2,4-D amine, aminocyclopyrachlor, aminopyralid, clopyralid, dicamba, fluroxypyr, picloram, and triclopyr on visible estimates of soybean injury, height reduction, maturity, yield, and yield components. Each of these herbicides was applied to soybean at the V3 and R2 stages of growth at 0.028, 0.28, 2.8, and 28 g ae ha−1. Greater height reductions occurred with all herbicides, except 2,4-D amine and triclopyr when applied at the V3 compared to the R2 stage of growth. Greater soybean yield loss occurred with all herbicides except 2,4-D amine when applied at the R2 compared to the V3 stage of growth. The only herbicide applied that resulted in no yield loss at either stage was 2,4-D amine. When applied at 28 g ae ha−1at the V3 stage of growth, the general order of herbicide-induced yield reductions to soybean from greatest to least was aminopyralid > aminocyclopyrachlor = clopyralid = picloram > fluroxypyr > triclopyr > dicamba > 2,4-D amine. At the R2 stage of growth, the general order of herbicide-induced yield reductions from greatest to least was aminopyralid > aminocyclopyrachlor = picloram > clopyralid > dicamba > fluroxypyr = triclopyr > 2,4-D amine. Yield reductions appeared to be more correlated with seeds per pod than to pods per plant and seed weight. An 18- to 26-d delay in soybean maturity also occurred with R2 applications of all synthetic auxin herbicides at 28 g ae ha−1except 2,4-D. Results from this research indicate that there are vast differences in the relative phytotoxicity of these synthetic auxin herbicides to soybean, and that the timing of the synthetic auxin herbicide exposure will have a significant impact on the severity of soybean height and/or yield reductions.

Weed Science ◽  
1988 ◽  
Vol 36 (5) ◽  
pp. 678-682 ◽  
Author(s):  
Prasanta C. Bhowmik

A 3-yr study was conducted to evaluate efficacy and soybean tolerance of cinmethylin. Cinmethylin was applied preemergence alone at 0.6, 0.8, and 1.0 kg ai/ha or in combination with metribuzin at 0.3 kg/ha. These treatments did not injure soybeans in field trials in 1984, 1985, and 1986. The combination of cinmethylin at 0.7 kg/ha and metribuzin at 0.3 kg/ha controlled more than 90% of large crabgrass, fall panicum, and yellow foxtail. Redroot pigweed and common lambsquarters control was also excellent. Residual control of all grass species was excellent for 8 weeks after preemergence application, followed by reduced control in two of the three grasses. The combination of cinmethylin and metribuzin at 0.7 and 0.3 kg/ha, respectively, significantly increased soybean yields compared to those of untreated plots. These yields were comparable with those obtained from the combination of alachlor and metribuzin at 2.0 and 0.3 kg/ha, respectively. Cinmethylin treatments had no adverse effects on soybean yield components including pods/plant, seed/pod, and seed weight. Cinmethylin shows potential as a preemergence herbicide for full-season weed control in soybean production.


2007 ◽  
Vol 55 (3) ◽  
pp. 339-345 ◽  
Author(s):  
A. Göksoy ◽  
Z. Turan

This study was made in order to determine the correlations between seed yield and some yield components, and the direct and indirect effects of these characters on seed yield in sunflower. Four experimental synthetic varieties (Syn 1s), their parental mixtures (Syn Os) and two standard varieties (open pollinated: Vniimk 8931, and commercial hybrid: Sunbred-281) were evaluated in replicated field trials under Turkish conditions in 1995, 1996 and 1997. Agronomic characteristics such as plant height, head diameter, number of seeds per head, 1000-seed weight and seed yield were observed for correlations and path coefficient analysis.According to the results, seed yield gave significant positive correlations with plant height, head diameter, number of seeds per head and 1000-seed weight. The highest positive correlation was observed between seed yield and number of seeds per head (r=0.890**). Path analysis indicated that the number of seeds per head gave the greatest direct effect (+0.7269) on seed yield, followed by 1000-seed weight (+0.3215) and head diameter (+0.1689). The percentage of direct effects on seed yield was 80.8%, 50.6% and 24.0% for number of seeds per head, 1000-seed weight and head diameter, respectively.


2021 ◽  
Vol 26 (01) ◽  
pp. 105-114
Author(s):  
Joseph Nwafor Akanwe Asiwe

Lack of improved and high-yielding adapted varieties constitutes limitation to cowpea (Vigna unguiculata (L.) Walp) production in South Africa. Therefore, field trials were conducted in two locations (the University of Limpopo Experimental Farm, (Mankweng) and Towoomba Research Station, Bela-Bela) during 2015–16 and 2016–17, to assess yield components, genotype x environment interaction as well as the adaptability of elite cowpea genotypes. The experiment was laid out using a randomized complete block design in three replications. Data were collected on flowering, maturity and yield components. Results revealed that “genotype, and genotype × year and genotype × location interactions were significant for most of the traits evaluated”. „The days to 50% flowering‟ and „90% maturity‟ ranged between 53 and 60 days, and between 89 and 96 days, respectively. The „100-seed weight‟ varied from 15.8 g to 22.5 g. „Broad-sense heritability‟ varied from 0 to 93% for days to maturity and grain yield, respectively. „Grain yield‟ varied from 1465.7 to 2594.9 kg ha-1, and the best yielders were lines „L2‟, „L10‟, and „L7‟. The „PC1‟ and „PC2‟ explained 82.57% variation for maturity, 79.12% for the „pods per plant‟, 83.78% for „seeds per pod‟, 93.09% for „100-seed weight‟ and 95.84% for „grain yield‟. Towoomba was a more productive location compared to Sykerfuil. Lines „L2‟, „L10‟, and „L7‟ yielded very well in both locations and years. This implies that they are adapted and are recommended for registration and commercial release in the region. © 2021 Friends Science Publishers


2020 ◽  
pp. 1-31
Author(s):  
Geoffrey P. Schortgen ◽  
Aaron J. Patton

The herbicide 2,4-D is used in a variety of cropping systems, especially in grasses since it is a selective postemergence broadleaf herbicide. However, the most common formulation (2,4-D dimethylamine) is antagonized when mixed in hard water. The objective of this research was to determine which formulations of 2,4-D or premixes of various formulations of synthetic auxin herbicides are subject to hard water antagonism. Formulations surveyed for hard water antagonism in the first experiment included 2,4-D dimethylamine, 2,4-D diethanolamine, 2,4-D monomethylamine, 2,4-D isopropylamine salt, 2,4-D choline salt, 2,4-D isooctyl ester, and 2,4-D ethylhexyl ester. Synthetic auxin formulation types in the second experiment included water-soluble, emulsifiable concentrates and emulsion-in-water. All formulations were mixed with both soft and hard water (600 mg CaCO3 L-1) and applied to dandelions to determine if antagonism occurred in hard water. Water-soluble (amine and choline) 2,4-D formulations were antagonized by hard water, but water-insoluble (ester) 2,4-D formulations were not antagonized. Similar results were found by formulation type with water-soluble synthetic auxin premixes antagonized but emulsifiable concentrates not antagonized. Further, water-soluble salt formulations were not antagonized when formulated in premixes with other synthetic auxin herbicides as an emulsion-in-water. This research demonstrates that all 2,4-D water-soluble formulations and water-soluble premixes with phenoxycarboxylic acid herbicides are subject to hard water antagonism. Formulations of 2,4-D containing emulsifying agents protect against antagonism by the water-insoluble nature of ingredients in their formulation.


2016 ◽  
Vol 30 (3) ◽  
pp. 629-638 ◽  
Author(s):  
Ti Zhang ◽  
Eric N. Johnson ◽  
Christian J. Willenborg

Desiccants are currently used to improve lentil dry-down prior to harvest. Applying desiccants at growth stages prior to maturity may result in reduced crop yield and quality, and leave unacceptable herbicide residues in seeds. There is little information on whether various herbicides applied alone or as a tank-mix with glyphosate have an effect on glyphosate residues in harvested seed. Field trials were conducted at Saskatoon and Scott, Saskatchewan, Canada, from 2012 to 2014 to determine whether additional desiccants applied alone or tank mixed with glyphosate improve crop desiccation and reduce the potential for unacceptable glyphosate residue in seed. Glufosinate and diquat tank mixed with glyphosate were the most consistent desiccants, providing optimal crop dry-down and a general reduction in glyphosate seed residues without adverse effects on seed yield and weight. Saflufenacil provided good crop desiccation without yield loss, but failed to reduce glyphosate seed residues consistently. Pyraflufen-ethyl and flumioxazin applied alone or tank mixed with glyphosate were found to be inferior options for growers as they exhibited slow and incomplete crop desiccation, and did not decrease glyphosate seed residues. Based on results from this study, growers should apply glufosinate or diquat with preharvest glyphosate to maximize crop and weed desiccation, and minimize glyphosate seed residues.


2010 ◽  
Vol 14 ◽  
pp. 67-73
Author(s):  
J.A.K. Trethewey ◽  
M.P. Rolston

In cereals, the importance of the flag leaf for contributing carbohydrate during seed fill is well documented. However, in ryegrass this relationship is not so clear. This paper reports on an investigation of the effect on seed yield components of reduced photosynthetic capacity to the flag leaf, stem and head of perennial ryegrass (Lolium perenne). The hypothesis was that reduced photosynthetic capacity of the flag leaf does not affect seed yield components in perennial ryegrass. Following flowering, photosynthetic capacity was reduced by defoliation or shading the flag leaf, stem, or head of individual tillers. Seed yield components were measured at harvest. Reduced photosynthetically active radiation (PAR) to the flag leaf and stem did not affect thousand seed weight or seed yield when compared with control plants whereas reducing PAR to the head had a significant effect. The seed head itself may be more important than the flag leaf during seed fill, but when the seed head is shaded substantial re-mobilisation of stored carbohydrates can occur. Keywords: flag leaf, green leaf area, Lolium perenne, photosynthetically active radiation, seed fill, seed yield, thousand seed weight, water-soluble carbohydrates


2021 ◽  
pp. 1-20
Author(s):  
Brian R. Dintelmann ◽  
Shea T. Farrell ◽  
Kevin W. Bradley

Abstract Non-dicamba resistant soybean yield loss resulting from dicamba off-target injury has become an increasing concern for soybean growers in recent years. After off-target dicamba movement occurs onto sensitive soybean, little information is available on tactics that could be used to mitigate the cosmetic or yield losses that may occur. Therefore, a field experiment was conducted in 2017, 2018, and 2019 to determine if certain recovery treatments of fungicide, plant growth hormone, macro- and micronutrient fertilizer combinations, or weekly irrigation could reduce dicamba injury and/or result in similar yield to soybean that was not injured with dicamba. Simulated drift events of dicamba (5.6 g ae ha−1) were applied to non-dicamba resistant soybean once they reached the V3 or R2 stages of growth. Recovery treatments were applied approximately 14 d after the simulated drift event. Weekly irrigation was the only recovery treatment that provided appreciable levels of injury reduction or increases in soybean height or yield compared to the dicamba-injured plants. Weekly irrigation following the R2 dicamba injury event resulted in an 1% to 14% increase in soybean yield compared to the dicamba-injured control. All other recovery treatments resulted in soybean yields similar to the dicamba-injured control, and similar to or lower than the non-treated control. Results from this study indicate that if soybean have become injured with dicamba, weekly irrigation will help soybean recover some of the yield loss and reduce injury symptoms that resulted from off-target dicamba movement, especially in a year with below average precipitation. However, yield loss will likely not be restored to that of non-injured soybean.


Author(s):  
SK Datta ◽  
MAR Sarker ◽  
FMJ Uddin

The experiment was carried out to study the effect of variety and level of phosphorus fertilizer on the yield and yield components of lentil at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during October 2009 to March 2010. Three lentil varieties viz. BINA masur 2, BINA masur 3 and BARI masur 4 and four levels of phosphorus viz. 0 kg P ha-1 (P0), 15 kg P ha-1 (P15), 30 kg P ha-1 (P30) and 45 kg P ha-1 (P45) were used in this experiment. Varieties showed significant influence on the all characters except plant height. The highest seed yield (1165 kg ha-1) was observed in BARI masur 4, and the lowest seed yield (1028 kg ha-1) was found in BINA masur 3. Phosphorus fertilizer had a significant effect on all the plant characters studied except 1000 seed weight. The highest seed yield (1222kg ha-1) was observed in P45 (45 kg P ha-1) treatment and the lowest seed yield (893 kg ha-1) was found in P0 treatment. In case of interaction, effect of cultivar and phosphorus fertilizer doses had a significant effect on all the plant characters studied except seeds pod-1 and 1000-seed weight. The highest seed yield (1317 kg ha-1) was obtained in V3 X P45 treatment, and the lowest seed yield (830 kg ha-1) was observed in V2 X P0 treatment combination. Among the varieties BINA masur 2 and BARI masur 4 were superior to BINA masur 3 in respect of yield performance with 30 kg P ha-1. BARI masur 4 fertilized with 30 kg P ha-1 produced the highest seed yield. Int. J. Agril. Res. Innov. & Tech. 3 (1): 78-82, June, 2013 DOI: http://dx.doi.org/10.3329/ijarit.v3i1.16097


2006 ◽  
Vol 28 (2) ◽  
pp. 45-52 ◽  
Author(s):  
Armando Martins dos Santos ◽  
Luis Mauro Gonçalves Rosa ◽  
Lucia Brandão Franke ◽  
Carlos Nabinger

The experiment was carried out in pots in a glasshouse, with one plant per pot and nine repetitions per treatment. The treatments consisted of free or restricted leaves, submited to 90-100% or 60-70% soil field capacity (FC). Only independent effects of water availability or leaf movement were observed on yield components. Plants under well-watered conditions and with freely orienting leaves were taller, and had a larger number of ramifications. The greater development favored the setting of a higher number of inflorescences per plant in these treatments. This behavior resulted in a high number of flowers, green and mature legumes per plant, thus resulting in high seed production which was the most evident response to water availability. Although individual seed weight was higher in the water stress treatment, total seed production was higher for well-watered plants, with no statistically significant effect of leaf movements.


2018 ◽  
Vol 32 (5) ◽  
pp. 597-602 ◽  
Author(s):  
Marcelo Zimmer ◽  
Bryan G. Young ◽  
William G. Johnson

AbstractSynthetic auxin herbicides such as 2,4-D and dicamba are often utilized to control broadleaf weeds in preplant burndown applications to soybean. Halauxifen-methyl is a new synthetic auxin herbicide for broadleaf weed control in preplant burndown applications to corn, cotton, and soybean at low use rates (5 g ae ha–1). Field experiments were conducted to evaluate efficacy and weed control spectrum of halauxifen-methyl applied alone and in mixtures with 2,4-D (560 g ae ha–1), dicamba (280 g ae ha–1), and glyphosate (560 g ae ha–1). Glyphosate-resistant (GR) horseweed was controlled with halauxifen-methyl applied alone (90% control) and in mixtures (87% to 97% control) 35 d after treatment (DAT). Common ragweed was controlled 93% with halauxifen-methyl applied alone and 91% to 97% in mixtures 35 DAT. Halauxifen-methyl applied alone resulted in poor giant ragweed control 21 DAT (73% control); however, mixtures of halauxifen-methyl with 2,4-D, dicamba, or glyphosate controlled giant ragweed (86% to 98% control). Halauxifen-methyl alone resulted in poor redroot pigweed control (62% control) 21 DAT; however, mixtures of halauxifen-methyl with dicamba, 2,4-D, or glyphosate controlled redroot pigweed (89% to 98% control). Halauxifen-methyl controls GR horseweed and common ragweed applied alone and in mixtures with other synthetic auxin herbicides and glyphosate. Furthermore, mixing 2,4-D or dicamba with halauxifen-methyl can increase the weed control spectrum in preplant burndown applications.


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