Submitted to: Agronomy Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/16/2009
Publication Date: 7/7/2009
Publication URL: naldc.nal.usda.gov/download/32836/PDF
Citation: Lagae, H.J., Langemeier, M., Lybecker, D., Barbarick, K. 2009. Economic Value of Biosolids in a Semiarid Agroecosystem. Agronomy Journal. 101: 933-939. Available online doi:10.2134/agronj2008.0209x Agron J 2009 101: 933-939. Interpretive Summary: Although municipal biosolids are widely used as a soil amendment on cropland in the US, little economic analysis has been done to determine its economic optimal application rate. In this article, data from a long-term study in Eastern Colorado where biosolids were applied in a winter wheat-fallow rotation on two sites was analyzed. The response of wheat yield to biosolids application rate was determined. The site on which biosolids had been applied since 1982 showed little response to added biosolids for most of the years analyzed (1993-2000), while the site which was started in 1992 showed a positive response of wheat yield to biosolids applied. The maximum wheat yield response was obtained from an application rate of 9.0 Mg/ha. Since the economically optimal level of biosolids to apply depends on the price received for the wheat as well as the total costs of the biosolids (including application costs), this optimal rate was determined for a range of wheat prices and biosolids costs. For a wheat price of $0.20/kg and a total cost of biosolids of $4.00/Mg, the optimal application rate was 7.3 Mg/ha. Finally, a comparison was made to the cost of commercial N fertilizer to obtain the value of the biosolids to the producer. In conclusion,it was determined that using biosolids as a soil amendment can have positive economic benefits; however, it needs to be monitored to avoid excessive nitrate accumulation or excessive levels of other nutrients or heavy metals.
Technical Abstract: Over half of the municipal biosolids generated in the U.S. are being applied to agricultural land. More information is needed on crop response to biosolids application and on the optimal level of the application from an economic prospective. With this in mind, data from two sites used in a long term biosolids application study of an Eastern Colorado wheat(Triticum aestivum L.)-fallow rotation was analyzed using multiple regression analysis. The site on which biosolids had been applied since 1982 showed little significant (p < 0.10) response to biosolids added for the years studied. These plots also averaged one third higher in total N in the top 20 cm of soil. The other site, started in 1993, showed a very significant response to biosolids. For this site the estimated maximum wheat yield was obtained at a biosolids application rate of 9.0 Mg/ha. The economically optimal level of biosolids to apply depended on both the price of wheat and the cost of the biosolids. With wheat price of $0.20/kg and a cost for biosolids (including application cost) of $4.00/Mg the optimal level of biosolids applied was 7.3 Mg/ha. Given an N fertilizer price of $1.10 per kg, a producer could afford to pay $7.47/Mg. Using biosolids as a soil amendment can have positive economic benefits; however, it needs to be monitored to avoid excessive nitrate accumulation or excessive levels of other nutrients or heavy metals.