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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 9 years

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

In March of 1995, the second year of a large-scale CRP take-out study with spring wheat was established. The plot size is 32' X 1100' with 4 replications. Initial residues taken on 1 March 95 averaged 6507 lbs/acre with a range from 2725 to 9220 lbs/acre. Glyphosate was applied at 16 oz/acre on 7 March 1995. Soil samples taken on 1 March 1995 to 4' showed total N to be 69 lbs/acre, P at 15 ppm, K at 523 ppm, S to 3' at 34 ppm, and an average of 8.2" of available soil moisture. Rainfall through the growing season was 5.2 inches. With a yield goal of 35 bu/ac we fertilized the plot on 30 March 1995 with 40-15-0-10 using McGregors's strawboss applicator and planted on the same day with Penawawa spring wheat at a rate of 80lbs/acre with a double disc drill on 7" spacings. MCPA was applied in early May. Line point residue cover was taken on 21Apr 1995. The plant stand was evaluated on 9 May 1995, and the plots were harvested on 28 July 1995.

Table 1. Results from spring CRP take-out study at Starbuck, WA, 1995.

Treatments	Residue Cover (%)	Plant Stand (plants/ft2)	Yield (bu/ac)	Test Weight (lbs/bu)	Protein (%)
1. plow - disc	9.4a	10.2a	43.0a	60.1a	10.4a
2. burn - sweep	9.7a	9.7a	41.6a	60.5ab	10.6a
3. disc - disc	34.9b	9.4a	39.3b	59.8b	10.5a
4. sweep - disc	33.9b	9.4a	37.8b	59.9b	10.3
LSD (10%)	7.6	0.9	1.8	0.4	0.5
CV (%)	26.9	7.3	3.4	0.6	4.0

Conclusion

The disc-disc and sweep disc treatments produced the highest percent residue cover, and this residue level did not significantly reduce plant stands. Rhizoctonia was prevalent throughout the trial and it did not appear to be treatment specific. The two low residue treatments (plow - disc and burn - sweep) showed yields and test weights significantly higher than the two high residue treatments. There was no significant differences in protein levels between treatments.

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