XXIInd International Multidisciplinary Scientific GeoConference Surveying, Geology and Mining, Ecology and Management – SGEM 2022
2 - 11 July, 2022
AMMONIA AND METHANE EMISSIONS FROM DIGESTED MANURE AFTER LAND APPLICATION
Frolova, O.; Grinfelde, I.; Pilecka-Ulcugaceva, J.; Berzina, L.
To achieve implementation of sustainable agriculture practices and implement circular bioeconomy in farms, agricultural waste and residuals commonly are used as feedstock for biogas production that is in line with European Union strategy to reduce methane emissions. Anaerobic digestion of feedstock results in production of the digestate. Digestate, on the one hand, is valuable fertilizer that can substitute synthetic fertilizers. On the other hand, it is associated with methane (CH4), ammonia (NH3) emissions and nitrate pollution in groundwater and watercourses. To asses the change of CH4 and NH3 emissions after application of digestate two short term field experiments was analyzed. In the first experiment digestate originated from pig slurry was applied to the soil on bare soil in spring. In the second experiment digestate originated from cattle slurry was applied to the soil with stubble in autumn. Measurements where done with cavity ring down spectrometer Picarro G2508 using static chamber methodology. Chamber volume was 60 l and measurement time - 400 s. Measurements where done before application (reference), immediately after application to the soil, after 2 h, 4 h and 24 h. The highest NH3 emission for digestate from pig manure was immediately after application 3.16 kg ha-1 h-1 that decreased to 1.73 kg ha-1 h-1after 2 h, 0.68 kg ha-1 h-1 after 4 h and 0.00008 kg ha-1 h-1 after 24 h. CH4 emission was the highest immediately after application (0.20 kg ha-1 h-1) but after 24 h emission corresponded to reference level. The highest NH3 emission for digestate from cattle manure was 2 h after application 1.20 kg ha-1 h-1 that decreased to 1.06 kg ha-1 h-1after 4 h, 0.26 kg ha-1 h-1 after 24 h. Immediately after application the highest measured NH3 emission was 0.93 kg ha-1 h-1. CH4 emission was the highest immediately after application (0.36 kg ha-1 h-1) but after 24 h emission corresponded to reference level.