Organic Waste N and P Dynamics Under Organic Waste N and P Dynamics Under Dryland Agroecosystems Dryland Agroecosystems Jim Ippolito and Ken Barbarick Jim Ippolito and Ken Barbarick USDA-ARS-NWISRL & USDA-ARS-NWISRL & Colorado State University Colorado State University
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Organic Waste N and P Dynamics Under Dryland Agroecosystems Jim Ippolito and Ken Barbarick USDA-ARS-NWISRL & Colorado State University.
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Organic Waste N and P Dynamics UnderOrganic Waste N and P Dynamics UnderDryland AgroecosystemsDryland Agroecosystems
Jim Ippolito and Ken BarbarickJim Ippolito and Ken BarbarickUSDA-ARS-NWISRL &USDA-ARS-NWISRL &
Colorado State UniversityColorado State University
Organic Waste Land Application Approach:
Agronomic rates based on crop N requirementsExcess P addition/accumulation
P-based vs N-based approach:P-based vs N-based approach:Utilizing long-term N-based data to make future
P-based decisions
Approach Account for all P added with organic waste (i.e.
biosolids) application. Account for all P removed with grain or straw. Determine total soil P at the end of the project.
• From the above, can we predict total P present?
What fraction(s) dominate P in this system?
Determine environmental risk based on the Colorado P Index Risk Assessment (Sharkoff et al., 2005).
Site InformationSite Information
Littleton/Englewood – CSU land application programLittleton/Englewood – CSU land application program Dryland wheat-fallow agroecosystemDryland wheat-fallow agroecosystem
• Applied every other year, except 1998Applied every other year, except 1998
• 3.6 x 16.8 m plots; 4 replicates; RCB design3.6 x 16.8 m plots; 4 replicates; RCB design
• Incorporated to 20 cmIncorporated to 20 cm
• 40 Mg ha40 Mg ha-1-1 biosolids plots history: biosolids plots history: 6.7 Mg ha6.7 Mg ha-1-1 in 1982, then 40 Mg ha in 1982, then 40 Mg ha-1-1 from 1984-1990 from 1984-1990
Barbarick, K.A., and J.A. Ippolito. 2007. Dryland wheat nutrient assessment for 12 years of biosolids applications. Agron. J. 99:715-722.Ippolito, J.A., K.A. Barbarick, and K.L. Norvell. 2007. Biosolids impact soil phosphorus recovery, fractionation, and potential environmental risk. J. Environ. Qual. 36:764-772.Kuo, S. 1996. Phosphorus. pp.869-919. In D.L. Sparks (ed.). Methods of Soil Analysis, Part 3 - Chemical Methods. Soil Science Society of America. Madison, WI.Sharkoff, J.L., R.M. Waskom, and J.G. Davis. 2005. Colorado Phosphorus Index risk assessment. Agronomy Technical Note No. 95 (revised). United States Department of Agriculture-Natural Resources Conservation Service and State of Colorado.Yingming, L., and R.B. Corey. 1993. Redistribution of sludge-borne cadmium, copper, and zinc in a cultivated plot. J. Environ. Qual. 22:1-8.