Return to CRP

Fall vs. Spring CRP Takeout -Summer Fallow - Fall Plant in Adams County

Lenard Roth,
with Baird Miller, Roger Veseth,
Timothy Walters, and Harry Schafer

Objective

Develop BMP's for optimizing tillage methods and timing for returning CRP land back to a rotation of fall or spring takeout - summer fallow - winter wheat.

Location: Adams County, north of Lind, WA
Soil Series: Ritzville-Willis association
Annual precipitation: 10 inches
Field history: Crested Wheatgrass for 8 years

Treatments

Fall disc - spring cultivate - skewtread - rodweed - rotary harrow - fertilize/cultivate - summer fallow - plant
Fall 2X harrow/chisel - spring skewtread - cultivate - rodweed - rotary harrow - fertilize/cultivate - summer fallow - plant
Spring disc - cultivate - skewtread - rodweed - rotary harrow - fertilize/cultivate - summer fallow - plant
Spring sweep - disc - rodweed - rotary harrow - fertilize/cultivate - summer fallow - plant
Fall flail - spring sweep - skewtread - rodweed - rotary harrow - fertilize/cultivate - summer fallow - plant

Comments

Initial residue levels taken on 21 September 1994, ranged from 3493 lbs/ac to 6412 lbs/ac, with an average of 4682 lbs/ac. The plot size is 25' X 1000' with 4 replications. The fall mow, fall disc and 2X harrow/chisel occurred in early October. Primary spring tillage operations began of 28 March 1995. Secondary tillage occurred on 29 March 1995. Soil samples taken on 17 April 1995 to 6' showed total N to be 128 lbs/ac, P at 2.5 ppm, K at 78 ppm, and S to 3' at 15 ppm. The plot was fertilized on 4 May 1995 with 49-0-0-0. Spring soil moistures to 6' were taken on 27 March 1995. The plot was planted on 31 August 1995 with Eltan winter wheat at a rate of 35 lbs/ac. Fall soil moistures to 6' were taken on 30 August 1995. Residue cover measurements were taken using the line point method. Surface picture roughness measurements were taken using D.K. McCool's random roughness pictures.

Table 1. Results from the fall vs. spring CRP take-out study at Adams Co., WA, 1995.

Treatment Available Moisture Spring 1995 (inches/6') Available Moisture
Fall 1995
(inches/6') Residue Cover
(6/1/1995)
(%) Residue Cover
(9/5/95)
(%) Plant Stand (plants/M²)

1. Fall disc

2.9d

1.9bc

24c

11.5c

57.7a

2. Fall 2X harrow

4.2c

1.8c

25bc

12.0bc

68.0a

3. Spring disc

4.7b

3.3a

21d

13.3abc

71.2a

4. Spring sweep

5.2a

2.3bc

28a

14.3ab

64.8a

5. Fall flail

4.8ab

2.6ab

27ab

15.0a

64.3a

LSD (10%)

0.4

0.7

2.0

2.4

9.4

CV (%)

6.9

24.1

6.3

14.5

11.4

Table 2. Results from the fall vs. spring CRP take-out study at Adams Co., WA, 1995.

Treatment Surface Roughness (Picture 7/11/1995)
(inches) Surface Parallel Roughness 7/95
(chain method in cm) Surface Roughness
(Picture 9/5/95)
(inches)

1. Fall disc

0.37b

8.5bc

0.61ab

2. Fall 2X harrow

0.40b

8.2bc

0.58b

3. Spring disc

0.47a

9.1bc

0.63ab

4. Spring sweep

0.50a

11.3a

0.69a

5. Fall flail

0.53a

10.0ab

0.67ab

LSD (10%)

0.06

1.6

0.09

CV (%)

11.5

13.3

12.2

Conclusion

Available soil moisture decreased dramatically throughout the summer fallow period for all treatments. The fall disc and fall harrow treatments retained the least amount of moisture and residue. Residue cover also decreased for all treatments during the summer fallow period. Plant stands were not significantly different between treatments. Surface roughness (picture) increased in all treatments from planting with the spring tillage treatments producing the greatest roughness.

Contact us: Hans Kok, (208)885-5971 | Accessibility | Copyright | Policies | WebStats | STEEP Acknowledgement
Hans Kok, WSU/UI Extension Conservation Tillage Specialist, UI Ag Science 231, PO Box 442339, Moscow, ID 83844 USA Redesigned by Leila Styer, CAHE Computer Resource Unit; Maintained by Debbie Marsh, Dept. of Crop & Soil Sciences, WSU