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Biosolids Effects on Grain Yield and Test Weight

Grant Miller
with Andy Bary, Craig Cogger WSU-Puyallup; Dan Sullivan Oregon State University;
Dan Sturgill and Sara Brallier, King County; and Mikki Kisson O’Neil and Sons

Compare biosolids to aqua ammonia for grain yield and test weight on dryland wheat in Adams County.

Location 15 mi. SE of Lind, WA, 1 mi. S of Hwy. 26.
Annual precipitation: 10 inches
Soil : mapped as a Ritzville silt loam; soil is sandier than typical Ritzville soil.
Rotation: wheat 94-95, fallow 93-94 and wheat 92-93

Check (no fertilizer)
Aqua ammonia - 45 lb N/ac with 5 lb S/ac as 12-0-0-26
Biosolids- 3, 4.5 and 6 dry ton/a

Biosolids from a King County wastewater treatment plant located in Renton, WA were applied with a manure spreader on 30 November 93. All plots were 70 by 700 ft. Biosolids were incorporated the day after application by chiseling. Biosolids contained 109 lb total N and 22 lb ammonium-N per dry ton. Moro winter wheat was planted on August 25, 1994 and due to poor seedling establishment areas were replanted on October 25, 1994. Wheat was harvested July 21, 1995 from a 40 ft by 600 ft strip in the center of each plot. We collected a grain sample for test weight from each plot as the grain was augered from the weigh wagon.

Data

Test Weight, lb/bu
Treatment	Rep 1	Rep 2	Rep 3	Rep 4	Average
Check	60.7	61.5	61.5	61.7	61.4a
Aqua Ammonia	60.6	61	61.3	61.8	61.2a
Biosolids 3.0 T	59.8	59.1	60.4	59.8	59.8b
Biosolids 4.5 T	58.9	58.6	59.7	59.6	59.2c
Biosolids 6.0 T	58.5	58.8	59.4	59.3	59.0c
LSD(5%)					0.47
CV					0.5

Conclusion

Biosolids at 3 and 4.5 dry T/ac increased grain yield by 5 bu/ac over aqua ammonia. Grain yield of biosolids at 6 dry T/ac was equal to aqua ammonia. The decrease in yield and test weight at 6 dry T/ac was probably due to increased water stress caused by excessive vegetative growth in the spring. The test weights of unfertilized and aqua ammonia were greater than the biosolids treatments. The 3 dry T/ac biosolids rate produced the highest grain yields and adequate test weight.

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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