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ARS Home » Southeast Area » Raleigh, North Carolina » Soybean and Nitrogen Fixation Research » Research » Publications at this Location » Publication #150461
Title: NITROGEN AVAILABILITY OF ANAEROBIC SWINE LAGOON SLUDGE: SLUDGE SOURCE EFFECTS

Author
item MOORE, AMBER - NC STATE UNIV
item Israel, Daniel
item MIKKELSEN, ROBERT - NC STATE UNIV

Submitted to: Bioresource Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2004
Publication Date: 1/5/2005
Citation: Moore, A.D., Israel, D.W., Mikkelsen, R.L. 2005. Nitrogen availability of anaerobic swine lagoon sludge: sludge source effects. Bioresource Technology.

Interpretive Summary: Increased numbers of swine producers will be removing sludge from their lagoons in the next few years, mainly due to an increase in lagoons exceeding sludge capacity. Information on availability of nitrogen (N) in the sludge is needed to improve application recommendations for crops. The objectives of this study were to investigate possible effects of different companies and types of swine operations (sow, nursery or finishing) on the availability of N in sludge from their associated lagoons. Company and type of swine operation had no significant effects (0.05 probability level) on availability of sludge N. Nitrogen availability for all sludge sources averaged 39% of the total Kjeldahl N applied after 8 weeks of incubation. Approximately 45 % of this available N was NH4-N contained in the applied sludge and 55% was derived from mineralization of organic N in the sludge. Results of this study demonstrate that the same N availability coefficient for sludge from lagoons of different types of swine operations can be used when calculating the amount of sludge required to provide a certain amount of plant available N for a receiver crop.

Technical Abstract: Increased numbers of swine producers will be removing sludge from their lagoons in the next few years, mainly due to an increase in lagoons exceeding sludge capacity. Information on availability of nitrogen (N) in the sludge is needed to improve application recommendations for crops. The objectives of this study were to investigate possible effects of different companies and types of swine operations on the availability of N in sludge from their associated lagoons. A laboratory incubation study was conducted to quantify the availability of N in the sludge. Nine sludge sources from lagoons of sow, nursery and finishing operations of three different companies were mixed with a loamy sand soil (200 mg total Kjeldahl N.kg-1 soil) and incubated for three months at 25 plus/minus 2 degrees C. Samples were taken at 8 times over the 3 month period and analyzed for nitrate and ammonium. Company and type of swine operation had no significant effects (0.05 probability level) on availability of sludge N. Thus, a quadratic plateau curve was fit to inorganic N (NH4-N + NO3-N) accumulation data for all sludge sources (r2 = 0.52) which demonstrated that inorganic N accumulation in the sludge amended soil attained a plateau at 8 weeks. The value of the positive Y intercept (0 incubation time) for this relationship represents the amount of NH4-N in the applied sludge and net inorganic N accumulation between 0 and 8 weeks represents mineralization of organic N in the sludge. Nitrogen availability for all sludge sources averaged 39% of the total Kjeldahl N applied after 8 weeks of incubation. Approximately 45 % of this available N was NH4-N contained in the applied sludge and 55% was derived from mineralization of organic N in the sludge.