Agronomy and Crop Sciences Commons^™

Nutrient Management Strategies To Control Broomsedge Infestation And Improve Yield And Quality Of Tall Fescue Hayfields, Junior I. Yasuoka, Dale Helwig, Wendie Powell, Jaymelynn K. Farney, Gretchen F. Sassenrath, Bruno C. Pedreira

Kansas Agricultural Experiment Station Research Reports

A study in tall fescue hayfields infested with broomsedge and bluestem was conducted at four locations in southeast Kansas. The purpose of this study was to evaluate how phosphorus, nitrogen, and potassium fertilization affect yield, forage quality, and broomsedge/bluestem control in tall fescue hayfields. This trial will be repeated in 2023.

Effect Of Corn Row Spacing On Herbicide Effectiveness For Weed Control In 2022, S. H. Lancaster, E. Adee

Kansas Agricultural Experiment Station Research Reports

Cultural weed control practices such as narrow row spacing can be a key component of successful weed management. Experiments were conducted in the Kansas River Valley to evaluate interactions of herbicide programs and corn row spacings on weed control and grain yield. There were no differences in weed control at a site with low weed density. However, at a site with high Palmer amaranth density, Resicore applied to 15- and 30-inch rows and Bicep + Acuron applied to 15-inch rows resulted in the greatest weed control. Corn yield was similar across all treatments at both locations.

Weed Control With Imiflex In Igrowth Forage Sorghum, R. S. Currie, P. W. Geier, S. H. Lancaster, C. M. Weber

Kansas Agricultural Experiment Station Research Reports

Igrowth (imidazolinone-resistant) forage sorghum hybrids were recently commercialized in Kansas. Even though the active ingredient of the herbicide associated with these systems, imazamox, is used in other crops, data are needed to define best practices for use in forage sorghum. The objective of experiments in Manhattan and Garden City, KS, was to investigate the use of ImiFlex (imazamox) herbicide in Igrowth (imidazolinone-tolerant) forage sorghum. At Garden City, volunteer corn and johnsongrass control 29 days after treatment was 90% or greater in all treatments that included ImiFlex. Similarly, Palmer amaranth control 28 days after treatment was 91% or greater at Manhattan. …

Imiflex Evaluation At Two Kansas Locations In Igrowth Grain Sorghum, P. W. Geier, R. S. Currie, S. H. Lancaster, C. M. Weber

Kansas Agricultural Experiment Station Research Reports

Herbicide-tolerant grain sorghums, such as Igrowth (imidazolinone-resistant) hybrids were recently commercialized in Kansas. Even though the active ingredient of the herbicide associated with these systems, imazamox, is used in other crops, data are needed to define best practices for use in grain sorghum. The objective of these studies was to evaluate ImiFlex (imazamox) herbicide in Igrowth grain sorghum at two Kansas locations in 2022. ImiFlex applied postemergence provided 93% volunteer corn control, and 90 to 95% johnsongrass control regardless of application timing at Garden City. At Manhattan, ImiFlex controlled Palmer amaranth 90 to 99%. Early season grain sorghum injury was …

Allelopathic Potential Of Winter Wheat Varieties For Weed Suppression, C. Bott, A. Dille, A. Mohammad, L. Simão, L. O. Pradella, R. P. Lollato

Kansas Agricultural Experiment Station Research Reports

Summer weeds are an expensive economic and environmental problem during the fallow period following the harvest of a wheat crop. Anecdotal evidence suggests that different wheat varieties impact the need for weed control in the subsequent fallow period differently, with reasons ranging from residue amount and quality to the allelopathic potential of such residue. Thus, our objectives were to compare the allelopathic effects of different winter wheat varieties on weed and crop germination suppression. We collected the residue left after harvest of 25 varieties grown in a randomized complete block design in two Kansas locations (Hays and Great Bend) during …

Glyphosate-Resistant Palmer Amaranth Control In Xtendflex Soybean, R. Liu, V. Kumar, T. L. Lambert

Kansas Agricultural Experiment Station Research Reports

XtendFlex soybean is a triple-stacked trait technology that allows growers to use dicamba (XtendiMax) and glufosinate (Liberty) for in-season control of glyphosate-resistant (GR) weed species, including Palmer amaranth. A field study was conducted at the Kansas State University Agricultural Research Center (KSU-ARCH) near Hays, KS, to determine the effectiveness of POST applied XtendiMax and Liberty alone or in sequential applications for GR Palmer amaranth control in XtendFlex soybean. The study site had a natural infestation of GR Palmer amaranth. Results showed that early post-emergence (EPOST) applications of XtendiMax or Liberty followed by (fb) a late post-emergence (LPOST) application …

Assure Ii Alone And With Tacoma And Classic For Efficacy In Fallow, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of this trial was to compare Assure II (quizalofop) at two rates with or without tank mix partners for grass control in fallow. Assure II at either rate alone provided similar control of volunteer corn and barley. Corn control was 90% or more regardless of rating date with all herbicides except Assure II at 8.0 oz/a plus Classic (chlorimuron) at 42 days after treatment (DAT). Tacoma (fenoxaprop) at 3.5 or 5.4 oz/a added to Assure II at 8.0 oz/a improved barley control later in the season.

Imiflex Rates For Efficacy In Imidazolinone-Tolerant Grain Sorghum, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of this study was to compare ImiFlex rates and timings for efficacy and crop response in imidazolinone-tolerant grain sorghum. Volunteer corn and Johnsongrass control was generally best when ImiFlex (imazamox) was applied postemergence (POST), except when tank mixed with Huskie (bromoxynil/pyrasulfotole). Likewise, Palmer amaranth control was most consistent when ImiFlex was applied POST. Though all herbicides increased grain yields relative to the weedy controls, yields increased the most when Moccasin II Plus (metolachlor) plus Motif (mesotrione) preemergence (PRE) was followed by ImiFlex POST or Moccasin II Plus and Sharpen (saflufenacil) PRE was followed by ImiFlex plus atrazine POST.

Reclaiming Old World Bluestem Pasture With Imazapyr Application And Native Grass Overseeding, Keith Harmoney

Kansas Agricultural Experiment Station Research Reports

Old world bluestems (OWB), mainly Caucasian bluestem (Bothriochloa bladhii) and yellow bluestem(Bothriochloa ischaemum)introduced from parts of eastern Europe, Asia, Africa, and Australia, have been shown to reduce abundance and diversity of some insect and wildlife species compared to native grasses when these OWB grasses form dense stands. These OWBs have been invading native pastures in the southern Great Plains and are rapidly increasing in the amount of area occupied in Kansas. Two landowners purchased pasture property in Ellsworth County, KS, and observed that Caucasian old world bluestem had increased in the pasture significantly over the course …

Roundup 2022: Agricultural Research Center-Hays

Kansas Agricultural Experiment Station Research Reports

Roundup is the major beef cattle education and outreach event sponsored by the Kansas State University Agricultural Research Center - Hays. This report communicates timely, applicable research information on beef production and rangeland topics.

Katagon At Two Timings Compared To Standards In Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of this trial was to compare Katagon (tolpyralate/nicosulfuron) to standard treatments for weed control in corn. Katagon plus atrazine applied early postemergence was as effective as any herbicide tested on the weeds present. When application timing was delayed to late postemergence, most herbicides were less effective. Early season corn injury was minor and did not persist. Although most herbicide treatments increased yields relative to the non-treated control, yields were generally best when any treatment was applied early postemergence.

Firstact For Efficacy In Accase-Tolerant Grain Sorghum, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of this study was to compare FirstAct with several tank mix partners for efficacy in herbicide-tolerant grain sorghum. FirstAct (quizalofop) alone or in tank mixtures controlled Johnsongrass 94% or more. However, tank mixing FirstAct with any broadleaf herbicide was generally antagonistic to Palmer amaranth control. Minor sorghum injury was 5% or less by four weeks after postemergence treatment. Sorghum yields increased with all postemergence treatments except with atrazine alone.

Industrial Weed Control With Plainview, Esplanade, And Method Application Timings, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of this trial was to compare Plainview, Esplanade, and Method at three applications for season-long weed control in noncropland. Glyphosate alone provided no residual weed control. Plainview (indaziflam/aminocyclopyrachlor/imazapyr) at 64 oz/a applied in the early or late fall controlled kochia similarly to Krovar (bromacil/ diuron) late in the season. Either rate of Plainview, as well as the tank mixture of Esplanade (aminocyclopyrachlor) plus Method (indaziflam), provided complete woollyleaf bursage control regardless of application timing. No treatment of Krovar controlled woollyleaf bursage more than 60%.

Single And Split Herbicide Applications For Efficacy In Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of this study was to compare season-long weed control from single and sequential herbicide applications in corn. Control of all weed species was generally good (90% or more) early in the season regardless of preemergence (PRE) herbicide. However, Russian thistle and Palmer amaranth control was best later in the season when a PRE herbicide was followed by a postemergence (POST) treatment. While all herbicide treatments increased yields compared to the untreated control, yields were greatest when Lumax EZ PRE (atrazine/mesotrione/metolachlor) was followed by Acuron (atrazine/bicyclopyrone/mesotrione/metolachlor) and glyphosate POST.

Pyraflufen Tank Mixtures For Efficacy In Fallow, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of this study was to compare Vida (pyraflufen) tank mixtures for glyphosate- resistant kochia control in fallow. Early-season kochia control was best with tank mixtures that included Sharpen (saflufenacil), but tank mixtures including dicamba provided the best control later in the season. No herbicide controlled kochia more than 80% late in the season. All herbicides controlled downy brome more than 90% within 14 days after treatment, and 100% by 21 days after application.

Fall-Planted Cover Crops For Weed Suppression In Western Kansas, S. Dhanda, V. Kumar, A. K. Obour, A. Dille, J. D. Holman

Kansas Agricultural Experiment Station Research Reports

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 …

Response Of Conventional Sorghum To Imiflex, Zest Wdg, And Firstact, R. Liu, V. Kumar, M. Marrs, T. L. Lambert

Kansas Agricultural Experiment Station Research Reports

Grass weed control in sorghum has been a serious challenge for sorghum growers. The newly developed herbicide-tolerant (HT) sorghum technologies such as igrowth, Inzen, and Double Team sorghum will allow growers to use IMIFLEX, ZestWDG, and FirstAct respectively, for in-season weed control. However, the adoption of these HT sorghum technologies may increase the use of these labeled herbicides and increase the likelihood of herbicide drift or tank contamination to conventional sorghum. Three separate field studies were conducted at Kansas State University Agricultural Research Center (KSU-ARCH) near Hays, KS, to understand the response of conventional sorghum to various rates of IMIFLEX, …

Confirmation And Control Of Imazamox-Resistant Shattercane, V. Kumar, R. Liu, T. L. Lambert, R. Perumal, B. Bean

Kansas Agricultural Experiment Station Research Reports

Shattercane is a summer annual grass weed species commonly found in grain sorghum producing regions, including Kansas. Recent development and commercialization of grain sorghum hybrids with tolerance to acetolactate synthase (ALS) and acetyl-CoA-carboxylase (ACCase) inhibiting herbicides will allow producers to use these herbicides for in-season control of shattercane. In a recent field survey, three shattercane populations (DC8, GH4, and PL8) collected from sorghum fields in northwestern Kansas survived the field-use rate (6 fl oz/a) of postemergence (POST) applied IMIFLEX (imazamox). The main objectives of this research were to (1) confirm and characterize the level of resistance to imazamox in those …

Herbicide Activity On Old World Bluestems, Keith Harmoney

Kansas Agricultural Experiment Station Research Reports

Two main species of old world bluestems (OWB), yellow bluestem (Bothriochloa ischaemum) and Caucasian bluestem (Bothriochloa bladhii), have encroached on rangelands, pastures, and road right-of-ways in Kansas. Patches of these OWB have been shown to reduce species diversity and abundance at multiple trophic levels, and pose a long-term threat to native plant, insect, rodent, and grassland bird populations. These OWB species are utilized by cattle early in the growing season, directly following prescribed burns, and during droughts when other forages lack water uptake and may go dormant. However, these OWB species mature more quickly than native …

Impact And Liberty Rates And Mixtures For Efficacy In Corn, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of the study was to compare Impact (topramezone), Liberty (glufosinate) and a premixture of the two herbicides (Sinate) for efficacy in corn. Rates for each herbicide were 0.75 and 1.0 oz/a for Impact, 22 and 30 oz/a for Liberty, and 21 and 28 oz/a for Sinate. Impact and Sinate, each at the high rates, and Status plus glyphosate provided the best kochia control for corn late in the season. These treatments, along with the low rate of Impact controlled crabgrass the best. Status was also the best treatment for Russian thistle, Palmer amaranth, and green foxtail control. The …

Pixxaro Alone And In Combination For Weed Control In Fallow, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of this study was to compare Pixxaro (halauxifen/fluroxypyr) alone and in combinations for weed control in fallow. Pixxaro alone was equal to or better than Banvel, Starane Ultra, or glyphosate alone for kochia control. However, the best kochia control occurred when these herbicides were mixed in various combinations. Similarly, Pixarro controlled flixweed equally as well as Banvel, Starane Ultra, or glyphosate at 7 days after treatment but flixweed control was complete regardless of herbicide later in the season.

Fallow Weed Control With Vida Tank Mixtures, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of the study was to compare Vida (pyraflufen) with various tank mix partners for glyphosate-resistant kochia control. Flixweed control was complete in fallow with all herbicides by 28 days after treatment. Kochia control was best when Vida was applied with glyphosate and Spartan. However, due in part to the extremely dry conditions, no treatment controlled kochia by more than 83% at 28 days after treatment, and kochia control began to decline after this 28 DAT.

Effects Of Prescribed Fire Timing On Native Plant Composition, Forage Biomass Accumulation, And Root Carbohydrate Reserves In The Kansas Flint Hills: Year 2 Of 6, Z. M. Duncan, A. J. Tajchman, M. P. Ramirez, J. Lemmon, W. R. Hollenbeck, D. A. Blasi, K C. Olson

Kansas Agricultural Experiment Station Research Reports

Objective:The objective was to document the effects of prescribed fire timing on native plant composition, forage biomass, and root carbohydrate concentrations in key native tallgrass species in the Kansas Flint Hills.

Study Description:This experiment was conducted at the Kansas State University Beef Stocker Unit. Eighteen pastures were grouped by watershed and assigned to one of three prescribed-burn treatments: spring (April 7 ± 2.1 days), summer (August 21 ± 5.7 days), or fall (October 2 ± 9.9 days). Botanical composition, forage biomass, and root carbohydrate concentrations in big bluestem, little bluestem, Indian grass, and purple prairie clover were evaluated …

Weed Control With Imazamox Rates And Timings In Herbicide-Tolerant Grain Sorghum, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

The objective of this trial was to evaluate weed control and crop response using imazamox (KFD-365-02) in herbicide-resistant grain sorghum. Palmer amaranth control was 80% or less late in the season due to the herbicide-resistant weed biotype in the experiment. Both velvetleaf and shattercane control exceeded 90% with most herbicides late in the year. Using KFD-365-02 at the 9.0 oz/a rate applied preemergence alone or with atrazine or Moccasin II Plus controlled green foxtail and puncturevine the best. Most early postemergence treatments caused minor sorghum necrosis 6 days after treatments, but sorghum recovered fully within one week.

Foxtail Management In Smooth Brome Hay Meadows, S. R. Lancaster, S. R. Duncan

Kansas Agricultural Experiment Station Research Reports

Three different herbicides were applied at early bromegrass greenup and at post hay harvest to assess their effectiveness in controlling foxtail at two producer hay meadow sites in Pottawatomie (PT) and Dickinson (DK) counties. Pendimethalin applied early resulted in the greatest foxtail control, but control did not extend through the season to reduce late-summer infestations. Metsulfuron applied early resulted in approximately 30% visible brome injury. The injury was associated with 77 and 48% brome hay losses when compared to the untreated check, at the PT and DK sites, respectively. Injury from the early spring treatments was exacerbated by six freeze …

Efficacy Of Imiflex, Zest, And Assure Ii On Green Foxtail Control, V. Kumar, I. Effertz, T. Lambert, R. Liu, B. Bean

Kansas Agricultural Experiment Station Research Reports

Grass weeds pose a serious management challenge in grain sorghum. Recent development of three herbicide-tolerant grain sorghum technologies such as Inzen, Igrowth, and DoubleTeam will provide the opportunity for producers to use nicosulfuron (Zest), imazamox (Imiflex), and quizalofop-p-ethyl (FirstAct) for grass weed control, respectively. The main objectives of this research were to (1) determine the effectiveness of Imiflex applied preemergence (PRE) on green foxtail control in comparison to commonly used group 15 herbicides; (2) compare the efficacy of Zest, Imiflex, and Assure II applied early- or late-POST at two different rates; and (3) determine the tank-mix compatibility of Zest, Imiflex, …

Auxinic Herbicide Mixtures For Controlling Multiple Herbicide-Resistant Kochia In Fallow, V. Kumar, T. Lambert, R. Liu, R. S. Currie, P. W. Stahlman

Kansas Agricultural Experiment Station Research Reports

Kochia resistant to glyphosate (Roundup), chlorsulfuron (Glean), and dicamba (Banvel or Clarity) has become quite common in the U.S. Great Plains, whereas multiple resistance to additional herbicides, including fluroxypyr (Starane Ultra), atrazine (AAtrex), and metribuzin (Sencor) has also been reported recently. Effective management of these multiple herbicide-resistant (MHR) kochia populations warrants the need of alternative herbicide strategies. The main objective of this research was to investigate the efficacy of auxinic herbicides, including Duplosan (dichlorprop-p), Weedone (2,4-D), Clash (dicamba), and/or Pixxaro (premix of halauxifen and fluroxypyr) alone or in various combinations for controlling MHR kochia. Separate greenhouse and field experiments were …

Effect Of Tank-Mixing Glyphosate, Dicamba, And Graminicides On Grass Weed Control In Roundup Ready 2 Xtend Soybeans, R. Liu, I. Effertz, T. Lambert, A. Jhala, V. Kumar

Kansas Agricultural Experiment Station Research Reports

The adoption of Roundup Ready 2 Xtendsoybean allows growers to use dicamba (Xtendimax or Engenia) in mixtures with glyphosate (Roundup PowerMax) or graminicides (Select Max or Assure II) for broad spectrum weed control. However, anecdotal evidence suggests that Xtendimax may cause antagonism when applied with Select Max and/or Assure II herbicides. The main objective of this study was to determine the effectiveness of Roundup PowerMax, Select Max, and/or Assure II alone or in tank-mixtures with Xtendimax for grass weed control in Xtendsoybean. Field studies were conducted in 2020 at the Kansas State University Agricultural Research Center (KSU-ARC) near Hays, KS, …

Control Of Volunteer Enlist Corn In Enlist E3 Soybean, R. Liu, I. Effertz, T. Lambert, V. Kumar

Kansas Agricultural Experiment Station Research Reports

Recent development of Enlist corn allows the use of 2,4-D choline (Enlist One), glyphosate (Roundup PowerMax), glufosinate (Liberty), and aryloxyphenoxypropionate (FOPs) herbicides for controlling grass and broadleaf weeds. However, volunteer Enlist corn plants can cause infestation in subsequent Enlist E3 soybean (resistant to 2,4-D, glyphosate, and glufosinate) in areas where a corn-soybean rotation is commonly practiced. The main objective of this research was to determine the effectiveness of cyclohexanedione (DIMs) herbicides alone or in tank-mixtures with Enlist One for Enlist corn control in Enlist E3 soybean. A field study was conducted in the 2020 growing season at the Kansas State …

Zest Application Timings For Efficacy In Grain Sorghum, R. S. Currie, P. W. Geier

Kansas Agricultural Experiment Station Research Reports

This study was conducted to compare Zest (nicosulfuron) herbicide at two rates and two application timings for efficacy in grain sorghum. Palmer amaranth control was best when a preemergence (PRE) herbicide was followed by a late postemergence (LPOST) treatment. Zest at 0.67 or 1.33 oz/a provided the best velvetleaf and shattercane control. Either rate of Zest applied early postemergence (EPOST) controlled green foxtail more than 90%, but the higher rate was required for greater than 90% control when applications were delayed until LPOST.