Tillage and Cropping Systems to

Increase Dryland Crop Production in

Southwest Oklahoma

by Gary Strickland

Extension Educator – OCES

Jackson County

Team Approach

• OSU’s IPM Program

• Area Extension Staff – Mr. Jerry Goodson (SWREC), Dr. Mark Gregory, Mr. Rick Kochenower, Mr. Terry Pitts, and Daniel Skipper

• State Extension Staff – Dr. J.C. Banks, Mr. Shane Osborn, Dr. Jeff Edwards, Dr. Chad Godsey, Dr. Randy Taylor

• OAES – Mr. Rocky Thacker and SWREC Crew,

• Jackson County OCES Program

• Local and Private Industry Sponsors (i.e.; Oklahoma Grain Sorghum Producers, Seed Companies, Coops, etc…)

Objectives of the Study

• Determine the impact of different cropping systems on resident insect populations

• Determine the effect of tillage and cropping management systems on weed species population dynamics

• Determine and demonstrate the effects of tillage and crop rotation on the economic components of weed, insect, and yield management in cotton, wheat, and grain sorghum production systems in Southwest Oklahoma

• To estimate the effects of tillage and cropping systems on SOM accumulation

Study Design

• Randomized Complete Block with a Split

Plot Design

• Two Tillage Systems

• Three Crops (Cotton, Wheat, Grain

Sorghum)

• Seven Cropping Systems (C-W-GS, C-W,

C-GS, W-DCGS-C, W, C, GS)

Summary of Insect Data

• To date, no significant differences have been noted between tillage treatments or among cropping systems regarding insect populations or species.

• Crop scouting principle has been reinforced in this study

• When a buildup of insect pests occurs a corresponding buildup of beneficial insects has occurred

Table 5. Wheat Insects 2002/2003

Treatment∞

‡ Greenbug Parasitized Greenbugs Beneficials

Weekly Counts

†

6 7 7 8 9 10 6 7 8 9 10

4. W-DCGS-C (NT) 2.7 2.7 75 46 5.7 3.3 64 13 28 6.3 7.0

6. W (NT) 1.7 0.3 61 15 10 5.0 70 16 15 6.0 13

11. W-DCGS-C (CT) 5.3 0.3 80 12 5.0 6.3 84 13 9.3 7.0 5.0

13. W (CT) 1.7 0.7 63 7.7 4.0 4.3 64 9.0 6.7 5.3 8.0

Pest and Beneficial Insect Relationship

0

10

20

30

40

50

60

70

80

90

Nu

mb

ers

of

Tota

l In

sect

s fr

om

both

Sw

eep

an

d L

inea

r

Foot

of

Row

Cou

nts

Insect and Week Count: Greenbug (GB); Parasitized Greebug (PGB); Beneficial (B)

IPM PRINCIPLE REINFORCED - 2002/2003 WHEAT

W-DCGS-C (NT)

W (NT)

W-DCGS-C (CT)

W (CT)

0

5

10

15

20

25

30

35

NT - Week 6 CT - Week 6 NT - Week 7 CT - Week 7 NT - Week 8 CT - Week 8

Nu

mb

ers

of

Tota

l In

sect

s fr

om

both

sw

eep

s an

d l

inea

r ro

w

foot

cou

nts

Weeks of Insect Buildup and Decline

IPM Principle Reinforced

2007 Cotton Crop

Aphids

Beneficials

Soil Organic Matter Management - Importance

in Dryland Crop Production

• Soil Erosion Prevention

• Increased Soil Water Storage Capacity

• Increased Water Infiltration Rates

• Decreased Soil Evaporation Rates

• Increase of In-Season Precipitation Use Efficiency

• Increased Organic Matter Pool

• Increased Cation Exchange Complex (CEC)

• Increased Anion Exchange Complex (AEC)

• Decrease in Soil Compaction in the Long Term

TS C-W-

GS

C-W C-GS W-

DCGS-

C

C W GS Mean L.S.D.

(.05)

NT 2.00(2)

1.49(6)

1.93(2)

1.63(6)

2.03(2)

1.84(6)

2.08(2)

1.71(6)

2.13(2)

1.71(6)

1.94(2)

1.68(6)

2.42(2)

1.79(6)

2.08(2)

1.69(6)

NS(2)

NS(6)

CT 1.76(2)

1.64(6)

1.87(2)

1.83(6)

1.82(2)

1.70(6)

1.84(2)

1.72(6)

1.79(2)

1.69(6)

1.96(2)

1.87(6)

2.06(6)

1.69(6)

1.87(2)

1.73(6)

NS(2)

0.13(6)(.10)

(2) 2 inch sampling depth; (6) 6 inch sampling depth

Tillage by Crop Rotation System SOM

Comparisons (2002-2008).

0

5

10

15

20

25

30

35

40

45

Soil resistance, kPa

0 1000 2000 3000 4000 5000 6000 7000

Soi

l dep

th, c

m

0

5

10

15

20

25

30

35

40

45

C-W-GS

C-W

C-GS

W-DCGS-C

C

W

GS

Rotations

Water content, g g-1

0.12 0.15 0.18 0.21 0.24 0.27

Table of significanceRotation / Tillage

*** / ***

*** / ns

*** / *

*** / ***

*** / ***

* / ***

ns / ***

A

B

Organic Matter Summary

• The interaction between tillage systems and cropping systems was

significant at the .05 probability level therefore comparisons should

be primarily between cropping systems within a tillage system.

• Soil organic matter accumulation, in general, indicate no significant

differences between cropping systems within tillage treatments to

date with the exception of the 6 inch sampling depth in the CT

cropping systems. But the data does reflect a trend across cropping

systems of increasing organic matter content in the top two inches

when compared to the six inch depth in both systems, NT systems are

38% higher and the CT systems are 16% higher.

• However, a significant difference between the two systems does exist

(as indicated by the significant interaction) with the NT systems

showing higher levels of SOM across all cropping systems, except for

the W only system, at the 2 inch layer.

Summary of Weed Data

• Only a few significant differences have been noted to date between tillage treatments or among cropping systems

• In general the NT systems show higher weed populations than the CT systems

• Common weed species that continue to be present in the field include: common purslane, prickly lettuce, winter grasses (bromegrass species primarily), marestail, and henbit

• New weed species that have appeared with time include: honeyvine milkweed, morningglory, red stem filaree, and common groundsel.

• To date current herbicide programs seem to be working in terms of weed population control with the exception of the Grain Sorghum No-Till Mono-Crop where significant increase in pigweed species occurred and has remained after a glyphosate and two atrazine herbicide applications; and common groundsel in the cotton systems.

2006 Cotton Weed PopulationsTreatments Common

Purslane

Prickly

Lettuce

Pigweed

C-W (NT) 1.0ψ (P.E.)

0.0 (P.H.)

0.5 (P.E.)

0.5 (P.H.)

0.5 (P.E.)

0.0 (P.H.)

C (NT) 4.3 (P.E.)

0.0 (P.H.)

0.3 (P.E.)

0.0 (P.H.)

4.0 (P.E.)

0.0 (P.H.)

C-W (CT) 0.0 (P.E.)

0.0 (P.H.)

0.0 (P.E.)

0.0 (P.H.)

0.7 (P.E.)

0.0 (P.H.)

C (CT) 0.0 (P.E.)

0.0 (P.H.)

0.0 (P.E.)

0.0 (P.H.)

0.0 (P.E.)

0.0 (P.H.)

Ψ: Weed numbers are from counts taken in 1/1000 of an acre.

Post-E Pigweed Counts in 2008

Grain Sorghum Systems

Tillage

System

C-GS GS Mean L.S.D.

(.05)

NT 5.8ψ 57.2 31.5 24.2

CT 0.33 0.5 0.42 NS

Ψ: Numbers are counts taken in 1/1000 of an acre

0

5000

10000

15000

20000

25000

30000

Wee

ds/

A

Cropping Systems by Tillage Treatment

Grain Sorghum Crop System Average Weed Population

(Pre-Harvest) 2002-2008

0

20000

40000

60000

80000

100000

120000

140000

160000

Pigweed (PE) Groundsel (PH)

Pla

nts

-T

ho

usa

nd

/Acr

e

Weed Species by Tillage and Cropping System

2009 Cotton Weed Counts

C-W-NT

C-GS-NT

C-NT

C-WCT

C-GS-CT

C-CT

Crop Herbicide SystemsHerbicide Time of

Applica-

tion

Mode of

Action

Group

Crop

Use

Crop

Rotation

Intervals

(M)

Broadleaf

Tank

Mixes

Grazing

Restric-

tion

(Days)

Roundup

(Glyphosate)

Pre, Post, HA Inhibition of

EPSP Syn. (9)

C, W, GS All Crops –

0M

Yes 0 Days

Dual

(metolachlor)

Pre & Post Shoot

Inhibitors (15)

GS, C W-4.5M; C &

GS – Next

Spring

Yes Do not feed

Maverick(sulfosulfuron)

Post ALS Inhibitor

(2)

W C &GS – 12M Yes 0 Days

Osprey

(mesosulfuron-

methyl)

Post ALS Inhibitor

(2)

W C – 3M; GS-

10M

Yes 0 Days

Olympus Flex Post ALS Inhibitor

(2)

W C & GS –

12M

Yes 0 Days

Finesse Grass &

Broadleaf

Post ALS Inhibitor

(2)

W C & GS -

Bioassay

Yes 7 Days

Axial XL Post ACCase

Inhibitor (1)

W C & GS – 4M Yes 30 Days

Crop Herbicide Systems Continued

Herbicide Time of

Applica-

tion

Mode of

Action

Group

Crop Use Crop

Rotation

Intervals

(M)

Broadleaf

Tank

Mixes

Grazing

Restric-

tion

Power Flex Post ALS

Inhibitor (2)

W C & GS –

9M

Yes 7 Days

MCPA Post Synthetic

Auxin (4)

W After

Harvest

Yes 7 Days

Harmony

ExtraPost ALS

Inhibitor (2)

W C & GS –

1.5M

Yes NA

Peak

(prosulf-

uron)

Post ALS

Inhibitor (2)

W & GS W – 0M

GS – 1M

C – 18M

Yes 30 Days

Basagran

(bentazon)

Post PS II

Inhibitor (6)

GS W-0M

C – 0M

Yes

Buctril

(bromoxy-

nil)

Post PS II

Inhibitor (6)

GS W – 1M

C – 1M

Yes 45 Days

Atrazine Post PS II

Inhibitor (5)

GS See Label Yes 21 Days

Crop Yield and Economic Responses

538

425

557

640

364

486

169

554 552

371

0

100

200

300

400

500

600

700L

int

Yie

ld (

Lb

s./A

)

Cropping Systems by Tillage Treatment

Average Cotton Yields 2003-2008

74

59

15

49

64 63

37

42

0

10

20

30

40

50

60

70

80

Yie

ld (

Bu

./A

)

Cropping Systems by Tillage Treatment

Wheat Yields 2003-2008

1649

2831

0

2690

0

1743

0

1932

0

500

1000

1500

2000

2500

3000Y

ield

(L

bs.

/A)

Cropping Systems by Tillage Treatment

Grain Sorghum Yields 2003-2008

-20

0

20

40

60

80

100

120

140

160

1 2 3 4 5 6 7

Do

lla

rs P

er a

cre

Cropping System Treatments

Cropping Systems by Tillage Average Crop Year System Returns:

2003-2009

NT

CT

C-W

-GS

C-W C-G

S

W-D

CG

S-C

C W

GS

-40

-20

0

20

40

60

80

100

120

140

160

1 2 3 4 5 6 7

Do

lla

rs P

er A

cre

Cropping System Treatments

Cropping System by Tillage Adjusted Average Crop Year System

Returns: 2003-2009 (mono-crops minus 2007)

NT

CT

C-W

-GS

C-W

C-G

S

W-D

CG

S-C

C W

GS

Production Economic Summary for 2003-2009

• While not always significant, the NT crop systems have shown a

consistent trend for higher return dollars beyond production

inputs than the CT systems.

• With only a few exceptions the crop rotations have indicated a

trend for higher yields and/or returns in the year by year

comparisons

• When averaged across years the NT C-W and

C-GS crop rotation systems are doing significantly better than the

mono-crop systems. However C and W only systems

(especially within the CT tillage system) have done surprisingly

well in comparison as all years are considered. This is somewhat

tied to the 2007 elevated crop year yields and commodity prices.

When the 2007 crop year is removed from the data then the NT

Rotation Systems and CT-CW rotation perform significantly

better.