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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #223430
Title: Predicting soil-extractable ZN, P, FE, and CU in a biosolids-amended dryland wheat agroecosystems

Author
item BARBARICK, K - COLORADO STATE UNIVERSITY
item Ippolito, James

Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2007
Publication Date: 3/1/2008
Citation: Barbarick, K.A., Ippolito, J.A. 2008. Predicting soil-extractable ZN, P, FE, and CU in a biosolids-amended dryland wheat agroecosystems. Soil Science. 173:175-185.

Interpretive Summary: Biosolids beneficial-use programs frequently involve multiple applications at agronomic rates, with plant-nutrient availability changing as elements react with soil constituents over time. Here, Barbarick and Ippolito present information which estimates plant availability of Zn, P, Cu, and Fe where multiple applications biosolids are applied to a dryland wheat-fallow agroecosystem. The authors completed planar (included the number of applications and elemental additions), linear, quadratic, and exponential-rise-to-a-maximum (as a function of elemental additions only) regression analyses for six applications at two sites, finding planar-regression models provided superior R squared values and standard errors of the estimate. Results suggested that lability changes as biosolids-borne Zn, P, Cu and Fe react with the soil over time. Nutrient availability predictions involving multiple biosolids applications should account for the number of biosolids additions.

Technical Abstract: Biosolids beneficial-use programs frequently involve multiple applications at agronomic rates, with plant-nutrient availability changing as elements react with soil constituents over time. Consequently, can regression equations reasonably estimate plant availability of Zn, P, Cu, and Fe where multiple applications of Littleton and Englewood (L/E), Colorado Wastewater Treatment Plant biosolids are applied to a dryland wheat (Triticum aestivum L.)-fallow agroecosystem? Before each growing season we added L/E biosolids at rates of 0 to 11.2 dry Mg/ha to plots arranged in randomized complete blocks with four replications per treatment. Soil samples collected after each wheat harvest were analyzed using an NH4HCO3-diethylenetriaminepentaacetic acid (AB-DTPA) extraction. We completed planar (included the number of applications and elemental additions), linear, quadratic, and exponential-rise-to-a-maximum (as a function of elemental additions only) regression analyses for six applications at two sites. We found that the planar-regression models provided superior R squared values and standard errors of the estimate in almost all cases. These results suggest that lability changes as biosolids-borne Zn, P, Cu and Fe react with the soil over time. Consequently, predictions of nutrient availability involving multiple biosolids applications to dryland wheat -fallow agroecosystems should account for the number of biosolids additions.