The purpose of this project was to evaluate the impact of manure and compost applications on the soil quality and productivity of eroded land. There were two on-farm research sites: one dryland and one irrigated. The dryland site was in a wheat-millet-fallow rotation located in eastern Weld County. The irrigated site was in continuous corn north of Fort Morgan in Morgan County. Both sites had existing eroded slopes with an approximate grade of 5%.

There were five treatments evaluated on each site. They were:

• 10 tons/acre of composted manure,
• 10 tons/acre of beef manure,
• 30 tons/acre of beef manure,
• 60 tons/acre of beef manure,
• and a control.

There were four replications at each site in a randomized complete block design. Treatments were applied in January 2000 and repeated in January 2001. Sampling was conducted in the spring and fall of 2000 and 2001.

Results

• Soil fertility improved at both locations (NO3-N, P, K, and Zn).
• Soil organic matter increased at both sites from about 0.7% to 0.9-1.0% following two years of the 30 tons/acre manure rate and up to 1.2% in the 60 tons/acre treatment.
• Water retention increased significantly in the 60 tons/acre plots at the dryland, no-till site at saturation, 1/3 bar, 1/10 bar, and 15 bars. Water holding capacity was also significantly increased.
• No difference in infiltration rate was measured at either site.
• Aggregate size distribution was altered at the dryland site with significantly more 1-2 mm aggregates in the 60 tons/acre treatment. On the irrigated site, aggregate stability of the 1-2 mm size fraction increased by 50% in the 60 tons/acre treatment as compared to the control (however, this was not statistically significant).
• In some cases, physical property improvements occurred at the 30 ton/acre rate, but the impacts tended to be much greater at the 60 ton/acre rate. However, soil NO3-N built up below the higher application rate.

Graduate Student: Greg Vlaming, currently with Colorado State University Extension in LaPlata County
Cooperator: Bruce Bosley, Colorado State University Cropping Systems Specialist
Farmers: Mertens and Poitz

Funding from the Colorado Agricultural Experiment Station

Colorado State University | CSU Extension | Dept. of Soil & Crop Sciences
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Last updated November 5, 2007 by Webmaster