Determining nitrogen fractions in swine slurry

Area of Science:

• Agricultural Science
• Environmental Science
• Animal Science

Background:

• Nutrient management plans (NMPs) are crucial for mitigating non-point source pollution from animal operations.
• Accurate manure analysis and nutrient availability indices are essential components of effective NMPs.

Purpose of the Study:

• To evaluate a modified method for determining nitrogen fractions in swine slurry.
• To calculate plant-available nitrogen (PAN) in swine manure.
• To characterize nitrogen fractions based on holding pit depth and animal growth stage.

Main Methods:

• Swine manure samples were collected from gestating sow and finishing pig holding pits at various depths.
• Nitrogen fractions (ammonium, amino acid, amino sugar) were analyzed.
• Plant-available nitrogen was calculated.

Main Results:

• Significant differences in ammonium, amino acid, and amino sugar concentrations were observed in gestation holding pits based on depth.
• Finishing pig holding pit nitrogen fractions did not show significant differences by depth.
• Plant-available nitrogen was approximately 74% for gestation and 67% for finishing barn manures.

Conclusions:

• Nitrogen fraction composition in swine slurry varies with holding pit depth, particularly in gestation facilities.
• Land application of swine manure should consider the specific nitrogen fractions present, which correlate with animal growth stage.
• This research provides insights for optimizing swine manure as a fertilizer resource.