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Research
Herbicides for Annual Ryegrass
Control
M.D. Plumer and S.A. Ebelhar
Two field studies were conducted at two locations to determine the efficacy of different herbicides on the control of annual ryegrass in row crop production. One study was conducted in Williamson county where treatments applied at two different stages of growth and in Hamilton county where a late planting was used because of wet conditions. The winter of 1997-98 was milder than average with above normal rainfall in the spring.
The variety used in the study was common Gulf and it was no-till drilled at 20 pounds/acre on Sept.28th and March 15th at the Williamson county site, and October 15th at the Hamilton county site. Herbicides were applied on May 22nd at Williamson county site and June 19th and June 23rd at Hamilton county. The September 28th seeding was fully headed at time of herbicide application; the March 15th seeding was in boot stage at time of herbicide application in Williamson county. At Hamilton county, the plot had received 1 quart of Roundup in May, and was in the mature stage when sprayed on June 19th. Ratings taken 10 days after spraying (10 DAS). Rating of 10 is perfect weed control.
| Table 1. Williamson county September 28th seeding |
Herbicide
Roundup Ultra
Roundup Ultra
Roundup Ultra
Gramoxone Extra
Gramoxone Extra
Touchdown
Touchdown
Fusion
Fusion
Check
Fultime
|
Rate/A.
1.0 pt
1.5 pt
2.0 pt
1.0 pt
2.0 pt
1.5 pt
2.0 pt
6 oz.
10 oz.
na
4.0 qt
|
Ryegrass control 10 DAS
9
10
10
9
10
10
10
10
10
2
9
|
| Table 2. Williamson county March 15th seeding |
Herbicide
Roundup Ultra
Roundup Ultra +2%N+pH 5.2
Roundup Ultra
Roundup Ultra
Roundup Ultra
Gramoxone Extra
Gramoxone Extra
Touchdown
Touchdown
Fusion
Sencor 75DF
Fultime
Check
|
Rate/A.
1.0 pt
8 oz.
1.0 pt
1.5 pt
2.0 pt
1.0 pt
2.0 pt
1.5 pt
2.0 pt
6 oz.
8 oz.
4.0 qt
na
|
Ryegrass control 10 DAS
9
8
9
10
10
9
10
10
10
10
3
10
2
|
| Table 3. Hamilton county |
Herbicide
Roundup Ultra
Roundup Ultra
Roundup Ultra
Gramoxone Extra
Gramoxone Extra
Touchdown
Touchdown
Fusion
Fusion
Check
|
Rate/A.
1.0 pt
1.5 pt
2.0 pt
1.0 pt
2.0 pt
1.5 pt
2.0 pt
6 oz.
10 oz.
na
|
Ryegrass control 10 DAS/45 DAS
8/3
8/8
9/9
9/9
10/10
9/10
9/10
10/10
10/10
7/7
|
+Fultime 4 qt./A
10
10
10
10
10
10
10
10
10
5 |
Ryegrass provided excellent suppression of other weeds at the Hamilton county site while the Williamson county had significant weed growth as well as excessive rainfall. Species were giant foxtail, teaweed, smooth pigweed, yellow nutsedge.
| Table 4. Hamilton county weed suppression burndown
herbicide only (45 DAS) |
Herbicide
Roundup Ultra
Roundup Ultra
Roundup Ultra
Gramoxone Extra
Gramoxone Extra
Touchdown
Touchdown
Fusion
Fusion
Check
|
Rate/A.
1.0 pt
1.5 pt
2.0 pt
1.0 pt
2.0 pt
1.5 pt
2.0 pt
6 oz.
10 oz.
na
|
Broadleaf
9
9
9
8
8
8
9
8
8
6
|
Grass
10
9
9
7
7
9
9
8
9
4
|
In the first year of the study it appears there is an advantage for the use of ryegrass in weed suppression. At the Williamson county site , ryegrass was easy to control at the boot stage as well as at early heading. Evaluation of the site on October 30th showed no evidence of ryegrass in the plots after no-till corn. Plots will be monitored next spring to see if any ryegrass has emerged.
Ryegrass As a Soybean Cover Crop
By Mike Plumer
Ryegrass can be used as a flexible cover crop to help in weed control and increase soil tilth. A study was designed to compare 15" rows to 7 ½" rows in no-till soybean production to compare weed control and yield.
Design of the project was 3 replications in a completely randomized block. Ryegrass was a blend of varieties of common ryegrass, planted at 20 pounds/ acre on Oct 2, 1999 by no-till drill. Previous crop was corn and the field has been in continuous no-till for 17 years. Soil test : 6.7 pH, 87 P1, 395 K20, organic matter 2.4% and Robbs soil type on 3 % slope. Planting methods: for the drilled plots a Marliss no-till drill with 7 ½" spacing, for the 15" rows a John Deere 7000 no-till planter planted to split the middles. Seeding rate: 220,000 seeds/acre of FS Hisoy 4426.
The ryegrass block was sprayed and planted on May 9, 2000. Herbicide was 24 oz. of Roundup Ultra in 10 gallon of pH adjusted water/acre (to 5.2 pH by citric acid) with 1 quart of 32% nitrogen and ½% surfactant. Fertility applied broadcast 125# of 18-46-0 and 180 # 0-0-60/acre. Ryegrass dry matter samples averaged 1538#/acre on the plots at planting.
| Table 1. Soybean population at 4 weeks |
Rows
15" rows
7 1/2" rows |
Rep 1
198,000
187,300 |
Rep 2
206,500
191,600 |
Rep 3
195,100
184,100
|
| Table 2. Soybean weed control at 4 weeks* |
Rows
15" rows
7 1/2" rows |
Grass
9
9
|
Broadleaf
8
9
|
*rating 1= no control, 10= perfect weed control
Weed control was not as good as expected with the grass weeds being giant foxtail, and the broadleaf weeds were smooth pigweed and annual morninglory. A post applied herbicide was used on all the plots: 6 oz. Fusion/ acre, 8 oz. Reflex/acre in 12 gallons water/ acre (adjusted to 5.2pH) with ½% surfactant and 2 quarts 32% nitrogen on June 7th. Rainfall during May 5.4" and June 8.9" probably reduced the level of weed control by the cover crop.
Weed control was evaluated again on July 3rd.
| Table 3. Soybean weed control at 8 weeks |
Rows
15" rows
7 1/2" rows |
Grass
10
10
|
Broadleaf
10
10
|
Plots were harvested on Oct 22, with no weeds present in any of the plots. The yields of the plots were adjusted to 13% moisture.
| Table 4. Soybean yield at 13% moisture bushels/acre |
Rows
15" rows
7 1/2" rows |
Rep 1
10
10
|
Rep 2
10
10
|
Rep 3
10
10
|
Ave.
10
10
|
| Cost of Production: per acre |
Seed
Fertilizer
Herbicides:
Roundup Ultra
Adjuvants
Fusion
Reflex
Adjuvants
|
$24.00
22.38
7.88
1.00
7.00
6.60
1.00
|
|
Total:$69.86 |
| Land Cost |
Land cost
Total variable costs
|
$75.00
$191.24
|
| Income |
15" rows
43.1bu. @ $5.45
7 1/2" rows
47.8 bu @ $5.45
|
$234.90
$260.51
|
return to labor/machinery
|
$43.66
$69.27
|
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