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Impact of Tillage on the Control of Glyphosate-Resistant Palmer amaranth. Culpepper, Kichler, York. Irrigated or Dryland. Production Practices. Irrigated - conventional? Irrigated – conservation tillage? Dry land - conventional? Dry land – conservation tillage?.
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Impact of Tillage on the Control of Glyphosate-Resistant Palmer amaranth. Culpepper, Kichler, York
Irrigated or Dryland
Production Practices • Irrigated - conventional? • Irrigated – conservation tillage? • Dry land - conventional? • Dry land – conservation tillage?
May 2008 Rainfall Distribution in Tifton (CPES) 1.4” 0.33” Herbicide activated 0.02” Dryland crops planted before May 9 or after May 16 did not get enough rain to activate residual herbicides!!! First rainfall event > 0.5” in June occurred on June 15 (1.03”)
Dry Land Management Tactics • Tillage • Cover Crops • Ignite-based programs • Various mixtures of all of these tactics
Objective • Determine the impacts of deep turning, incorporating a yellow herbicide, and cultivation on the management of glyphosate-resistant Palmer amaranth.
Experiment 1: Factorial: 2 deep tillage options 4 herbicide systems
Two Deep Tillage Options deep turn or no deep turn All land was disked prior to planting
Four Herbicide Options • no herbicide • WMax: 1, 5, 13 lf cotton • 3. Prowl H20 + Reflex PRE; • WMax + Dual Magnum POST 5 lf; • Direx + MSMA LPD 13 lf • Treflan PPI; • Reflex PRE; • WMax + Dual Magnum POST 5 lf • Direx + MSMA LPD 13 lf
Herbicides and Rates PPI or PRE POST Prowl H20 2.0 pt/A Dual Mag. 1.0 pt WeatherMax 22 oz/A Treflan 1.5 pt/A Reflex 1.0 pt/A Layby Direx 2 pt + MSMA 2 lb
Experiment 1: Methods Plot size: 4 rows by 30 feet Herbicide applications: 15 GPA Rainfall: Once inch occurred 5 d after planting Visual ratings:early and late-season Harvest: one-row cotton picker
Number of Palmer Amaranth Plants During Early Season. Macon Co., Georgia 2008.* No Deep Tillage Deep Turn No Herbicide Treatment
Percent glyphosate-resistant Palmer amaranth control at layby. Macon Co., GA. 2008.* 100 a 100 a 100 a 89b 67c 53 d 10 e RU 2X RU 2 X None Prowl system* Treflan system* Prowl system* Treflan system* Deep Tillage No Deep Tillage *System included Reflex PRE; WMax + Dual Mag. POST.
Percent glyphosate-resistant Palmer amaranth control at harvest. Macon Co., GA. 2008.* 98 a 94 a 90 a 79b 0 c 0 c 0 c RU 3X RU 3 X None Prowl system* Treflan system* Prowl system* Treflan system* Deep Tillage No Deep Tillage *System included Reflex PRE; WMax + Dual Mag. POST; Direx + MSMA directed.
No Deep Tillage Deep Turned Prowl H20 + Reflex PRE; WeatherMax + Dual Magnum POST; Direx + MSMA Layby
Seed Cotton Yield. Macon Co., GA. 2008.* 1550 a 1570 a 1430 a 1170 b 0 c 0 c 0 c RU 3X RU 3 X None Prowl system* Treflan system* Prowl system* Treflan system* Deep Tillage No Deep Tillage *System included Reflex PRE; WMax + Dual Mag. POST; Direx + MSMA directed.
Experiment 2: Methods Plot size:8 rows by 50 feet Herbicide applications: 15 GPA Rainfall: Once inch occurred 5 d after planting Visual ratings:early and late-season Harvest: one row cotton picker
Experiment 2: Treatments • Prowl H20 + Reflex PRE; • WMax + Dual POST; • Direx + MSMA LPD • 2. Treflan PPI; • Reflex PRE; • WMax + Dual POST; • Direx + MSMA LPD with and without cultivation
Percent glyphosate-resistant Palmer amaranth control at harvest. Macon Co., GA. 2008.* 88 a 78 a Prowl system* Treflan system* *System included Reflex PRE; WMax + Dual Mag. POST; Direx + MSMA directed.
Percent glyphosate-resistant Palmer amaranth control at harvest. Macon Co., GA. 2008.* 95 a 89 a 88 a 78 b Prowl system* Treflan system* + Cultivation *System included Reflex PRE; WMax + Dual Mag. POST; Direx + MSMA directed.
+ Cultivation Prowl System
Seed Yield as Impacted by Cultivation. Macon Co., GA. 2008.* 2275 a 2000 b 2050 b 1840 c Prowl system* Treflan system* + Cultivation *System included Reflex PRE; WMax + Dual Mag. POST; Direx + MSMA directed.
Summary • Deep turning reduced the number of Palmer amaranth that emerged at 1 month after planting by 60%. • Deep turning improved Palmer control of the Prowl PRE systems by 15% at harvest and increased yield 19%.
Summary 3. When not deep turning the land, incorporating the yellow herbicide improved control by 11% at harvest and increased yield 26%. 4. Cultivation improved control in the Prowl system by 11% and increased yield 6 to 10% in the Prowl or Treflan system
Conclusion Deep turning land, incorporating the yellow herbicide, and cultivation can all be used to improve control of glyphosate-resistant Palmer amaranth in dry-land Roundup Ready cotton production.