successful cogongrass suppression using loblolly pine ... · planting trench but a double deep...
TRANSCRIPT
Successful Cogongrass Suppression
using Loblolly Pine Reforestation
James Miller, US Forest Service R&D
Stephen Enloe, Auburn University Erwin Chambliss, US Forest Service R&D
AU Cogongrass Research Team: Dr. Stephen Enloe (Agron), Dr. Nancy Loewenstein (Forestry), Dr. Luke Marzan (Remote Sensing), and Dr. Jim Miller (Emeritus USFS R&D)
Cogongrass Rhizomes must be killed or removed for eradication
Integrated Vegetation Restoration for Cogongrass Management
Mechanical Herbicides
Cultural – Plant Something
The Study Site in the southern most county in Alabama, Mobile Co. Uniform infestation 10 years after farming ceased
Test Treatments for Establishing Loblolly
All Combinations of the 3 Main Treatments plus 2 extras
1. Mechanical Site Preparation “Scalping” treatment using fireplow behind a dozer Laid back a 6 to 10 inch deep layer of soil and rhizomes, creating a
planting trench but a double deep rhizome mat between rows
2. Herbicide Site Preparation – at 26 gallons total volume per acre Arsenal AC imazapyr 12 oz /A (1 % solution) Accord Conc glyphosate 0.8 gal /A (3 % solution)+
surfactant 0.5 % v/v
3. Pine release May or Oct - banded sprays over rows Arsenal AC 4 or 6 oz /A (0.3 % or 0.5 %) alone and mixtures with Oust 2 oz /A and/or Escort 1 oz /A
– Double Rate Herbicide SP and release with Arsenal + Escort+Oust Arsenal AC 24 oz/A (2% solution) + Accord 1.6 gal/A (6% solution) – Check Non-treated Plots
Experimental units: • Treatment Plot 100 trees ( 8 x 8 ft spacing = 650 trees/acre) • Measurement Plot 36 measurement trees • Cover 5 subplots
• 2 ½ gen ‘Super’ seedlings • Culled to > 0.25 in root collar diameter
25m (82 ft)
25m (82 ft)
36 Measurement Trees
100 Trees Treatment
Plot
Plot (82 x 82 ft) 8.2 x 8.2 ft spacing
650 trees/acre
1
3 4
5
2
5 Subplots for Cover
Study Site during Study Establishment
Each Planting Spot Kicked Down to Permit Optimum Planting without Grass Wicks
Second Generation seedlings were re-graded onsite To have over a 3/8th inch groundline diameter
Seedling after 1st growing season
A Farmer eradicated cogongrass on half of the Area By multiple plowings and then planting Roundup Ready
Crops that could withstand multiple Roundup Treatments
Mechanical Site Preparation (Scalping)
Cogongrass infestation reforestation by planting loblolly pine Seedling after herbicide SP + scalp and scalp alone
January 2001
2 x 2 meter spacing 8.2 x 8.2 ft, 650 trees /ac
In 1st growing season
Mechanical SP only Herbicide + Scalping
April of the 2nd growing season on Check
April or the 2nd Year on Herbicide Site Prep
April of 2nd Year Herbicide SP and Scalp
September after 3rd growing season Max Site Prep with early succession initiated which later was reinvaded by
cogongrass
August of the 6th Growing Season
After 8 Growing Seasons
Herbicide Site Prep 2X Rate + Fall Arsenal Release
Herb + Scalping Site Prep
After 8 Growing Seasons Significant Suppression has occurred
Plant Pines Only with yaupon, privet, and
waxmyrtle volunteer establishment and Pine cover with needle Litter layer
Herb Site Prep & Missing Tree permits light to
sustain cogongrass
Age 8 Cogongrass Cover (%)
Check 2x Herb SP + Release
Release Herb SP
Herb SP + Release
0
2
4
6
8
10
12
14
16 18
Spring Release with Arsenal AC 0.5 % alone best
Age 8 Loblolly Volume (ft3 / acre)
Check Release Herb SP
2x Herb SP + Release
Herb SP + Release
0
100
200
300
400
500
600
8% Inc
13% Inc
22% Inc
25% Inc
What We Learned
• Initial cogongrass control increased with the intensity of treatment and positively increased pine growth.
• Cogongrass re-invaded all plots by year 3 due to absence of eradication even after multiple treatments.
• Scalping site preparation that laid the rhizome mats back as a mound between pine rows sustained the cogongrass longer than other treatments, which is not advised as a useful treatment.
• Dense pine canopies with pine litter layers or pine canopies with woody shrub midstories suppressed cogongrass by an average of 84 to 99 percent after 8 years
• 8-yr pine volumes averaged 25 % greater with multiple treatments compared to the check. This should maintain where woody competition does not occur.
We Can Establish Loblolly Pine Plantations in Cogongrass Infestations for Suppression