Title

Evaluation of weed control options for soybean in SW North Dakota at Hettinger, 2024.

(Research Report, Hettinger REC, December 2024)

File

Publication File:

Evaluation of weed control options for soybean in SW North Dakota at Hettinger, 2024

Summary

A trial was conducted near Hettinger, ND to evaluate weed control options for soybean. Soybean were planted on May 20, 2024, into wheat stubble using a no-till planter at a depth of 1.5 inches at a seeding rate of 110,000 seeds/A. Soybean emerged on June 3. One weeks prior to planting, the entire plot area was treated with glyphosate (Roundup PowerMax) plus carfentrazone (Aim EC) to control emerged weeds. Treatments were applied either at planting (preemergence, PRE), after emergence of soybean at the V1 growth stage (early postemergence, EPOST), at the V2 soybean growth stage (postemergence, POST), or at the R1 growth stage (late postemergence LPOST) (Table 2). Weed control was evaluated at 5 and 8 weeks after the PRE treatment timing (WAT), with the 8 WAT evaluation occurring 1 weeks after the LPOST application. Weed evaluated in this trial included kochia, common lambsquarters, green foxtail, wild oat, and barnyardgrass. Herbicides applied at the PRE timing contain active ingredients that are active in the soil on seedling weeds. Herbicides applied at all postemergence timings were primarily foliar active on controlling emerged weeds. At 5 WAT, only PRE and EPOST treatments had been applied. At this evaluation, the only PRE treatment that resulted in good kochia control (89-91%) was Authority MTZ (sulfentrazone plus metribuzin). All others controlled kochia at 69-76%. Common lambsquarters was controlled at 88-100% by metribuzin, Authority MTZ, and Authority Supreme (sulfentrazone plus pyroxasulfone). Green foxtail and barnyardgrass were controlled 89-96% by Authority MTZ, Zidua (pyroxasulfone), and Authority Supreme. No PRE treatment provided good control of wild oat. EPOST treatments evaluated at this time included glyphosate, Liberty (glufosinate), glyphosate plus Xtendimax (dicamba), and Zalo (glufosinate plus quizalofop). For kochia control, products containing glufosinate provided better control that glyphosate. Glyphosate controlled wild oat better than glufosinate containing products.

At 8 WAT, the POST application of glyphosate improved weed control compared with PRE herbicides alone in nearly all cases. The best overall control occurred with sequential applications of Zalo (EPOST and LPOST), and with Authority MTZ (PRE) followed by glyphosate (POST). Plant stands and heights were not affected by herbicide treatments. The entire trial was treated with glyphosate two weeks after the LPOST timing to control weeds not controlled by earlier applications. Soybean yield was affected by drought conditions that occurred in July and August. Yields were very low and not commercially viable. However, the same two treatments have the best overall weed control 8 WAT also had the highest soybean yield. It would be interesting to evaluate these same treatments under better rainfall conditions. These herbicides show the importance of using multiple applications for weed control and not relying on a single herbicide or mode of action for weed control in soybean.

Lead Author

Lead Author:

Caleb Dalley

Availability

Availability:

Web only

Publication Sections

Table 1. Evaluation of herbicide options for weed control in soybean at Hettinger, ND, 2024

				Kochia^1,2					Lambsquarters				Green foxtail					Wild oat					Barnyardgrass					–––––––– Soybean³ ––––––––
		Rate	Timing	5 WAT		8 WAT		5 WAT			8 WAT			5 WAT		8 WAT			5 WAT		8 WAT		5 WAT		8 WAT			Stand		Height		Yield
Treatment⁴		oz/A		––––––––––––––––––––––––––––– % control –––––––––––––––––––––––––––––																								plants/A		inches		BU/A
1	Untreated			0	h	0	g	0		f	0	h		0	i	0	h		0	g	0	h	0	i	0		h	107393	-	7.1	-	1.6	ef
2	Roundup PowerMAX3	22	EPOST	81	def	61	e	100		a	96	ab		100	ab	83	de		96	a	96	ab	100	ab	83		de	115634	-	8.3	-	3.7	ab
3	Liberty	28	EPOST	100	a	87	bc	100		a	82	def		100	ab	77	ef		84	bc	82	def	100	ab	77		ef	110462	-	8.1	-	2.9	bcd
4	Xtendimax	22	PRE	72	fg	0	g	63		e	0	h		0	i	0	h		0	g	0	h	0	i	0		h	110235	-	7.7	-	1.2	f
5	Roundup PowerMAX3	22	EPOST	85	cde	87	bc	100		a	87	cde		99	ab	84	cde		94	a	87	cde	99	ab	84		cde	110393	-	8.0	-	2.8	bcd
	Xtendimax	22	EPOST
6	Xtendimax	22	PRE	76	efg	87	bc	73		de	94	abc		40	h	92	abc		0	g	94	abc	40	h	92		abc	97954	-	8.0	-	3.1	abc
	Roundup PowerMAX3	22	POST
	Xtendimax	22	POST
7	Zalo® Herbicide	32	EPOST	96	ab	100	a	100		a	97	ab		100	a	100	a		94	a	97	ab	100	a	100		a	106666	-	8.0	-	4.1	a
	Zalo® Herbicide	32	LPOST
8	Zalo® Herbicide	32	EPOST	97	ab	83	bcd	99		ab	80	ef		100	ab	84	cde		91	ab	80	ef	100	ab	84		cde	116609	-	7.6	-	2.0	def
	Dual II Magnum	21	PRE
9	Zalo® Herbicide	32	EPOST	95	ab	89	b	100		a	82	def		100	ab	90	bcd		92	ab	82	def	100	ab	90		bcd	105606	-	7.7	-	2.1	c-f
	Dual II Magnum	1.33	EPOST
10	Metribuzin	5.33	PRE	72	fg	52	e	90		bc	70	g		81	f	60	g		68	de	70	g	81	f	60		g	101214	-	8.2	-	2.0	c-f
11	Metribuzin	5.33	PRE	75	fg	86	bcd	88		cd	96	ab		74	g	90	bcd		66	e	96	ab	74	g	90		bcd	100531	-	7.7	-	3.8	ab
	Roundup PowerMAX3	22	POST
12	Authority MTZ	18	PRE	89	bcd	81	bcd	100		ab	78	f		89	de	80	ef		52	f	78	f	89	de	80		ef	97881	-	8.3	-	2.9	bcd
13	Authority MTZ	18	PRE	91	abc	91	ab	100		a	100	a		93	cd	95	ab		53	f	100	a	93	cd	95		ab	111197	-	8.6	-	4.1	a
	Roundup PowerMAX3	22	POST
14	Zidua SC	5	PRE	69	g	22	f	71		e	79	f		91	cd	73	f		75	de	79	f	91	cd	73		f	115858	-	7.5	-	2.3	cde
15	Zidua SC	5	PRE	70	g	75	d	82		cd	100	a		83	ef	95	ab		75	cd	100	a	83	ef	95		ab	108792	-	7.9	-	3.4	ab
	Roundup PowerMAX3	22	POST
16	Authority Supreme	9.8	PRE	72	fg	55	e	97		ab	90	bcd		96	abc	89	bcd		50	f	90	bcd	96	abc	89		bcd	104186	-	8.1	-	2.9	bcd
17	Authority Supreme	9.8	PRE	76	efg	78	cd	96		ab	100	a		94	bcd	96	ab		49	f	100	a	94	bcd	96		ab	104908	-	7.7	-	3.5	ab
	Roundup PowerMax3	20	POST
LSD P=.05				9.1		10.7		9.9			9.7			8.0		6.5			8.5		7.8		6.2		8.6			12627.3		0.93		0.98
Standard Deviation				6.4		7.6		6.9			6.8			5.6		4.6			5.9		5.5		4.4		6.0			8848.8		0.65		0.69
CV				8.21		11.31		8.32			9.62			6.91		6.19			8.88		7.04		5.5		7.9			8.02		7.84		22.41
Treatment Prob(F)				0.0001		0.0001		0.0001			0.0001			0.0001		0.0001			0.0001		0.0001		0.0001			0.0001		0.1440		0.0824		0.0001

Abbreviations: weeks after treatment, WAT; preemergence, PRE; early postemergence, EPOST; postemergence, POST; late post emergence, LPOST; acre, A; bushel, BU.

¹Means followed by same letter or symbol do not significantly differ (P=.05, LSD).

²Weed control evaluations were taken 5 and 8 weeks after the preemergence (PRE) herbicide application timing; Application timings were: PRE, at planting; early postemergence (EPOST), 29 days after planting at the V1 soybean growth stage; postemergence (POST), 36 days after planting; and late postemergence (LPOST) 50 days after planting.

³Soybean stand was measure 5 WAT; height was measured 8 WAT, and harvested 18 WAT

⁴Adjuvants were added to treatment mixtures according with label guidelines for each herbicide.

Table 2. Application environment and equipment for application of herbicide treatments for weed control in soybean.

Application Description					Application equipment
	PRE	EPOST	POST	LPOST		PRE	EPOST	POST	LPOST
Date	May-21-24	Jun-19-24	Jun-26-24	Jul-10-24	Type	Tractor	Tractor	Tractor	Tractor
Start Time	8:24 AM	8:45 AM	5:58 PM	12:10 PM	Pressure	42 PSI	42 PSI	42 PSI	20 PSI
Stop Time	8:49 AM	9:00 AM	6:23 AM	12:15 PM	Nozzle^a	11002DG	11002DG	11002DG	11002DG
Air Temperature Start/Stop	56 F	60 F	78.3 F	85.4 F	Spacing	20 IN	20 IN	20 IN	20 IN
% RH	59.3	50	43.4	42.9	Length	100 IN	100 IN	100 IN	100 IN
Wind Spped	7.1 MPH	0.9 MPH	6.2 MPH	2.9 MPH	Height	20 IN	28.0 IN	28.0 IN	36.0 IN
Wet Leaves (Y/N)	No	No	No	No	Speed	2.8 MPH	2.8 MPH	2.8 MPH	3 MPH
Soil Temperature	53 F	43 F	66 F	F	Volume	15 GAL/A	15 GAL/A	15 GAL/A	15 GAL/A
% Cloud Cover	100	5	10	5	Propellant	CO2	CO2	CO2	CO2

Evaluation of weed control options for soybean in SW North Dakota at Hettinger, 2024.

Table 1. Evaluation of herbicide options for weed control in soybean at Hettinger, ND, 2024

Table 2. Application environment and equipment for application of herbicide treatments for weed control in soybean.

This is the prefooter section