Assessment of Biologically Converted Swine Waste as a Fertilizer Source in Container Production

Abstract

Swine waste (SW), the by-product of North Carolina's booming hog industry, is one of the state's most underutilized resources. Currently, SW is used to grow coastal bermuda hay, a “disposal” crop with little to no economic value. Use of SW by commercial growers as fertilizer would reduce the need to dispose of SW and could reduce the overall input of nutrients into the environment. Our objectives were to determine: plant growth characteristics of SW, the effects of SW on leachable forms of nitrogen, and the physical effects of SW in a pine bark media. To avoid pathogens, we used SW (BionSoil™) that had been biologically digested as part of a proprietary SW treatment process (Bion Technologies, Inc.). Liners of `Rose Madness' petunia, `Skogholm' cotoneaster, `Girard's Red' azalea, and `Wilson's Yellow' daylily were planted in 3.8-L plastic pots that contained one of the following (by volume): 10% SW:90% pine bark, 20% SW:80% pine bark, 30% SW:70% pine bark, or pine bark (control) amended with 3.6 kg of 23-4-8 controlled release fertilizer (CLF), 3.6 kg dolomitic limestone, and 330 g micronutrient fertilizer per m3. Shoot dry weights were determined for all species at harvest. Root dry weights were obtained for cotoneaster and daylily. Leachate nitrogen and pH was determined periodically throughout the 22-week study. By the 14th week, nitrogen and potassium deficiencies were identified on plants growing in SW-amended media. Those treatments were subsequently topdressed with a corrective application of 9 g of 23N–4P–8K CRF. Generally, SW can produce plants similar to short-term CRF without the need for supplemental micronutrients or lime Root biomass was greater in SW media than in the control. A mid-season application of a N–P–K fertilizer may be necessary.