Manure from confined animal operations is an environmental liability because of the potential for water and air pollution. The poultry industry in the Chesapeake Bay watershed is under increased regulatory scrutiny due to nitrogen and phosphorous inputs into the Bay. Although poultry litter (PL) is valued as a fertilizer, the cost of shipping the bulky material out of the watershed is prohibitive. One potential solution is to turn the excess litter into energy through pyrolysis. If a market can be developed for poultry litter biochar, more N and P could be removed from the Chesapeake Bay watershed.
Our overall program goals are to develop a comprehensive strategy to convert poultry litter from an environmental liability into an economic and ecological asset and to develop a comprehensive conceptual model for improving poultry litter waste management through market-driven alternatives. Our specific objectives are to characterize the properties and variability of biochar from a commercial poultry/ litter biochar producer, evaluate PL biochar for two potential commercial uses; greenhouse plant production and as an amendment for degraded mine soils.
Why Is It Important to Develop Alternative Markets for Biochar?
Excess phosphorus (P) in the Chesapeake Bay watershed has created water quality problems within the Bay. A major source of this P originates from confined animal feeding operations (CAFOs); within the West Virginia portion of the watershed, primarily in the form of poultry production. The lack of sufficient, suitable cropland on which to spread the manure from these operations has created the need to export P out of the watershed. One potential solution to this challenge may come from the gasification of poultry litter. Gasification produces energy and a carbonaceous byproduct (Figure 1) for which a number of applications have been suggested, including use as a soil amendment. Our long-term objectives are to determine the beneficial uses for a commercially produced poultry litter biochar (PLB) with the goal of generating a market for PLBs that will promote the transport of P out of the Bay watershed. In this work, we describe the particle size distribution and nutrient content of two different pyrolysis oven batch runs of poultry litter from our commercial producer (M-type and W-type).We describe effects of these PLB types on lettuce seed germination and seedling growth and its use as a substitute greenhouse media for cyclamen production. We also describe the results of an experiment using PLB for mine soil reclamation and cellulosic biomass production.
What did we do?
M-Type and W-type PLBs were mechanically sieved into six size classes in duplicate and then extracted with dilute hydrochloric (0.05M) and sulfuric (0.05M) acids. Solution sodium (Na), potassium (K), calcium (Ca), magnesium (Mg) and P concentrations were determined and converted to mg (kg PLB)-1. Lettuce (Lactuca sativa var. Black Simpson) seed was planted into a commercial top soil amended with two rates of M-type biochar (3.18 g kg-1) and (9.09 g kg-1), some of which had been rinsed with water for 24 or 48 hours to remove salts, with no biochar and fertilizer controls, in two 8 x 8 Latin Square designs. In one Latin Square seedlings were thinned to two per cell and allowed to grow until root bound. Germination percent and dry mass were determined. The second PLB product (W-type) was used untreated as a substitute potting media for greenhouse cyclamen (Cyclamen persicum) production The treatments were a commercial mix, 1:1 peat:perlite + 64 g dolomitic lime or + 112 g W-type PLB. One of the products (M-type) was washed in tap water in an attempt to reduce salt content and then leached and unleached PLB (2.5 kg m-2) was used (lime and fertilizer controls) in a factorial experiment using switchgrass (Panicum virgatum) and Miscanthus sinensis transplants for mine soil reclamation.
What we have learned?
The M-type PLB had more, fine particles (<60 mesh) than did W-Type). The M-type fine particles (<60 mesh) had more Ca and K whereas the coarser W-type particles (>60 mesh) had more K. PLB did not have a significant effect on lettuce germination (> 85%) at either concentration or rinsing treatment. PLB treatments also had no effect on aerial biomass of lettuce yield. The inorganic fertilizer treatment was the only treatment with aerial biomass significantly different (higher) than the control. Cyclamen growth was initially slower, but by the end of the experiment, yields were equivalent. It is too soon to draw conclusions from the mine soil reclamation experiment.
We will continue monitoring switchgrass and Miscanthus growth and mine soil property changes in response to biochar applications and are seeking additional disturbed soil sites for new experiments. Because biochar is known to sorb metal contaminants, we have initiated laboratory experiments to evaluate the effectiveness of biochar for the remediation of brownfield sites. We also have plans to determine the stability of biochar in a variety of soils and the effects of biochar applications on soil microbial communities and greenhouse gas emissions.
Louis M. McDonald, Professor, LMMcDonald@mail.wvu.edu
Andrew Burgess, Research Assistant Professor
Jeff Skousen, Professor
Joshua L. Cook, Graduate Student
Walter E. Veselka, IV, Research Associate
James T. Anderson, Professor. Environmental Research Center, West Virginia University
Anderson, J. T., C. N. Eddy, R. L. Hager, L M. McDonald, J. L. Pitchford, J. Skousen, and W. E. Veselka IV. 2012. Reducing impacts of poultry litter on water quality by developing markets for energy and mine land reclamation. Athens: ATINER’S Conference Paper Series, No: ENV2012-0069. 12pp. http://www.atiner.gr/papers/ENV2012-0069.pdf
Support for this project was provided by NOAA, NSF, blue moon fund, Frye Poultry Farms, and the Davis College of Agriculture, Natural Resources and Design and Environmental Research Center at West Virginia University.
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