U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska
Date of this Version
2007
Abstract
The use and disposal of biosolids, or wastewater treatment sludge, as a fertilizer and soil amendment is becoming increasingly widespread. We evaluated the multiyear use of biosolids in apricot (Prunus armeniaca L.) production, grown on productive agricultural soils. Class A biosolids were initially applied annually at rates of 0, 1.9, 5.8, and 11.7 Mg · ha-1 (dry basis) to a 2-year-old apricot orchard on the USDAARS research site on the eastern side of the San Joaquin Valley, CA. These application rates provided estimated rates of 0 (control), 57, 170, and 340 kg total N · ha-1 yr-1, respectively. Compared to the control treatment, the applications of biosolids significantly increased soil salinity (electrical conductivity from 1:1 soil–water extract) and total concentrations of nutrients [e.g., calcium (Ca), magnesium (Mg), sulfur (S), phosphorus (P), zinc (Zn), and copper (Cu)] after 7 years but did not increase the concentrations of selected metals [cadmium (Cd), chromium (Cr), cobalt (Co), nickel (Ni), and lead (Pb)] between 0- and 60-cm soil depths. Mean concentrations of total nitrogen (N) and carbon (C) in soils (0- to 15-cm depth) ranged from a low of 1.3 g kg-1 to a high of 5.2 g · kg-1 and from 14.1 g · kg-1 to 45.7 g · kg-1 for the control and high biosolids treated soils, respectively.
Comments
Published in Communications in Soil Science and Plant Analysis, 38: 1533–1549, 2007. DOI: 10.1080/00103620701378474