A new technology combusts poultry litter mixed with dewatered swine wastes to generate electricity. Ash from this process, supplemented with phosphoric acid, was granulated to produce a 4.6% N, 27.9% P2O5, 3.6% K2O, and 1.3% S fertilizer. This composition may change as ongoing research adjusts the waste management and production process. Our study compares the effectiveness of this fertilizer with conventional P fertilizer (triple superphosphate, 0-46-0) in field and greenhouse studies. Corn, wheat, and soybean experiments evaluated P source and rate effects on soil test P (Mehlich-3), crop P uptake, fertilizer P recovery, and grain yield. Fields with historical P fertility gradients or low soil test P levels were utilized. Field experiments were located at the Peanut Belt Research Station (Lewiston) Piedmont Research Station (Salisbury), Tidewater Research Station (Plymouth), and Mountain Horticultural Crops Research and Extension Center (Fletcher) field sites. The Fletcher site also included barley, rye, and triticale. A total of 6 site-years of corn and wheat, and 4 site-years of soybean will be evaluated. All field tests include 3 or 4 replications and randomization of treatments. Fertilizer treatments were broadcast prior to planting. A P-responsive soil from the Tidewater Research Station (Portsmouth fine sandy loam, Typic Umbraquult) was used in the greenhouse study. Initial results found significant corn and wheat grain yield responses to P rate in 2004. No significant response of soybean to P rate was found. At one corn site and at one wheat site, 0-46-0 resulted in higher yields than did the ash-derived fertilizer. Since the majority of the P in the ash-derived fertilizer is citrate-soluble, rather than water-soluble, it may be slightly less available than similar amounts of P2O5 applied as 0-46-0. Additional grain yield and plant P uptake data will be presented.
See more of Soils Posters/Reception
See more of The ASA Southern Regional Branch (June 19-21, 2005)