Nutrient Preservation in Cattle Slurry via Emission Reduction during Storage with Calcium Cyanamide

Abstract

Cattle slurry storage is a considerable source of pollutant emissions due to microbial degradation of its components and subsequent volatilization. These emissions are directly linked to losses of essential nutrients, which are consequently no longer available for further use (e.g., in biogas plants or for fertilization). Here, we present the correlation between the application of calcium cyanamide (CaCN₂) as an additive for efficient mitigation of emissions from cattle slurry storage and the conservation of nutrients. Three series of laboratory storage experiments were conducted using fresh cattle slurry with and without CaCN₂ under semiaerobic conditions at ambient temperature for 4 months each. Emission measurements and detailed mass balances, based on slurry analyses and weighing, revealed a considerable reduction in greenhouse gas emissions by 76.3% and concomitant preservation of fresh matter (34.9%), carbon (47.2%), and nitrogen (96.3%) upon facile additive application. Thus, CaCN₂ can enhance the value of cattle slurry despite prolonged storage.