Return to Tillage Wheat/Fallow

Returning CRP Land to Spring Wheat

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

Location: Starbuck, WA Annual precipitation: 14 inches
Soil series: Walla Walla silt loam Field history: Crested Wheatgrass for 8 years

1. Plow - disc - fertilize - skewtread - plant
2. Burn - sweep - fertilize - skewtread - plant
3. Sweep - disc - fertilize - skewtread - plant
4. Disc - disc - fertilize - skewtread - plant

In the spring 1994, a large-scale CRP take-out study was established near Starbuck, WA in a CRP field that has been in crested wheatgrass for 8 years, on a Walla Walla silt loam soil with an average rainfall of 14 inches. The treatments included: 1) Plow - disc - fertilize - skewtread - plant; 2) Burn - sweep - fertilize - skewtread - plant; 3) Sweep - disc - fertilize - skewtread - plant; and 4) Disc - disc - fertilize - skewtread - plant. Plot size was 32' X 850' with 4 reps. Initial residues taken on 12 March 94 and levels averaged 6556 lbs/acre with a range of 2227 and 10,202 lbs/acre. Roundup was sprayed on all plots on 12 March 94 at 16 oz/acre prior to any tillage. Soil samples taken on 15 March 94 to 4' showed total N to be 97 lbs/acre, P at 18 ppm, K at 515 ppm and S to 3' at 7 ppm. The plot was fertilized on 16 March 94 with 70-15-0-15 and planted with Penawawa spring wheat at a rate of 80 lbs/acre on 20 Mar 94. MCPA was sprayed on 4 May 94 at a rate of 0.75 lbs/acre. Line point residues readings were taken on 19 Apr 94. Dryland foot rot readings were taken on 23 June 94, and the plots were harvested on 14 July 94.

Table 1. Results from spring CRP take-out study at Starbuck, WA, 1994.

Treatments	Residue Cover (%)	Plant Stand (plants/ft2)	Tillers Infected with Dryland Footrot (%)	Yield (bu/ac)	Test Weight (lbs/bu)
1. plow-disc	15.2b	7.4b	16.1b	18.14b	54.1b
2. burn-sweep	10.2a	7.7b	15.5b	17.89b	52.8a
3. sweep-disc	54.7c	5.5a	2.9a	14.53a	53.5ab
4. disc-disc	57.9c	5.5a	3.1a	14.37a	53.2a
LSD(10%)	3.3	0.7	4.1	2.04	0.72
CV	20%	16%	118%	9.7%	1.0%

Conclusion

The low initial soil water content in the upper 4' foot profile (on average 5.5 inches) and less than 3" of rainfall during the growing season resulted in yields much lower than our yield goals of 35 bu/ac. The plow-disc and burn-sweep treatments had the lowest final residue cover and highest plant stand. These treatments appeared to use the moisture more rapidly, increasing the incidence of dryland footrot. The low residue plow-disc and burn-sweep treatments had significantly higher grain yields.

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