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ARS Home » Pacific West Area » Kimberly, Idaho » Northwest Irrigation and Soils Research » Research » Publications at this Location » Publication #231920
Title: Water Treatment Residuals and Biosolids Long-Term Co-application Effects to Semi-arid Grassland Soils and Vegetation

Author
item Ippolito, James
item BARBARICK, K - COLORADO STATE UNIVERSITY
item STROMBERGER, M - COLORADO STATE UNIVERSITY
item PASCHKE, M - COLORADO STATE UNIVERSITY
item BROBST, R - U.S. EPA

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/27/2009
Publication Date: 11/1/2009
Citation: Ippolito, J.A., Barbarick, K.A., Stromberger, M.E., Paschke, M.W., Brobst, R.B. 2009. Water Treatment Residuals and Biosolids Long-Term Co-application Effects to Semi-arid Grassland Soils and Vegetation. Soil Science Society of America Journal. 73(6):1880-1889.

Interpretive Summary: We determined the long-term (13-15 years) effects of a single and short-term (2-4 years) effects of repeated WTR-biosolids co-applications on soil chemistry, soil microbiology, and plant community structure in a semi-arid grassland. The soil microbial community and AB-DTPA-extractable soil Al were relatively unaffected by WTR application, but extractable P and Mo decreased with increasing WTR rate due to adsorption by WTR; long-term effects were still evident. Plant tissue P and Mo content decreased with specific plant species and years, again due to WTR adsorption, yet no deficiency symptoms were observed, while plant community composition and plant cover were largely unaffected. Results suggested minimal environmental impact from the use of WTR in semi-arid grassland ecosystems.

Technical Abstract: Water treatment residuals (WTRs) and biosolids are byproducts from municipal water treatment processes. Both byproducts have been studied separately for land application benefits. There are possible environmental benefits of WTRs and biosolids co-application but these studies are limited. Our objectives were to determine relative long-term (13-15 years) effects of a single and short-term (2-4 years) effects of repeated WTR-biosolids co-applications on soil chemistry, microbiology, and plant community structure in a Colorado semi-arid grassland. Only relative changes associated between co-applications were studied, as we assumed WTR application would only occur if used as a management practice. Three WTR rates (5, 10, and 21 Mg/ha) were surface co-applied (no incorporation) with a single biosolids rate (10 Mg/ha) once in 1991 (long-term plots) and again in 2002 (short-term plots). Soil 0-8-, 8-15-, and 15-30-cm depth pH, EC, NO3-N, NH4-N, total C, and total N were not affected by WTR application in 2004, 2005, or 2006. Ammonium-bicarbonate diethylenetriaminepentaacetic acid- (AB-DTPA) extractable soil Al was relatively unaffected by WTR application, but extractable P and Mo decreased with increasing WTR rate due to WTR adsorption. Plant tissue P and Mo content decreased with specific plant species and years due to WTR adsorption; no deficiency symptoms were observed. Plant community composition and cover were largely unaffected by WTR application. Soil microbial community structure was unaffected by WTR co-application rate, although time since biosolids-WTR application affected a subset of microbial community fatty acids including markers for Gram-positive and Gram-negative bacteria. Overall, WTR-biosolids co-applications did not adversely affect semi-arid grassland ecosystem dynamics.