|Herrick, Jeffrey - Jeff|
Submitted to: Arid Soil Research And Rehabilitation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/27/2000
Publication Date: 1/1/2001
Citation: WALTON, M., HERRICK, J.E., GIBBENS, R.P., REMMENGA, M. PERSISTENCE OF BIOSOLIDS IN A CHIHUAHUAN DESERT RANGELAND 18 YEARS AFTER APPLICATION. ARID SOIL RESEARCH AND REHABILITATION. 2001. V. 15. P. 223-232. Interpretive Summary: Municipal biosolids (sewage sludge) are increasingly being applied to arid and semi-arid lands. There is little information on the long-term fate of these materials or on their long-term effects on rangelands. In this study we found that over 30% of biosolids applied 18 years previously to a degraded area near Las Cruces, New Mexico were still present as fragments greater than 2mm (about O.1 inch) in diameter. We also found no correlatio between vegetation and the concentration of biosolids, suggesting little if any long-term effect on the vegetation.
Technical Abstract: The experimental application of municipal biosolids to degraded arid and semi-arid rangelands has been practiced for many years and is becoming more common in the western United States. Previous studies have examined the effects of applying biosolids to land areas that have been degraded by one or more different factors including overgrazing, fire suppression, and increased drought frequency, duration, or intensity. However, few of these studies have measured the persistence of biosolids in the soil. This study is an attempt to recover information from an abandoned reclamation effort in which municipal biosolids were spread on a degraded rangeland on the Jornada Experimental Range in southern New Mexico. The biosolids were applied in 1979 and were still present in substantial amounts when soil samples were taken in 1997. An estimated 32% of the applied biosolids persisted as fragments greater than 2 mm in diameter for almost twenty years. There were no apparent benefits of biosolid application at this sit in terms of vegetation establishment within the first four years, and there was no correlation between vegetation patterns and the concentration of biosolids remaining in the soil in 1997. It is hypothesized that much of the applied sludge remains in the soil because of the recalcitrant nature of digested biosolids combined with the environmental conditions of soil in arid systems. Long-term results from biosolid addition experiments in arid and semi-arid rangelands should be considered before the practice is widely used for reclamation of degraded rangeland sites.