Location: Livestock Nutrient Management ResearchTitle: Condensed and hydrolyzable tannins for reducing methane and nitrous oxide emissions in dairy manure – a laboratory incubation study
|Min, Byeng Ryel|
|Willis, William - Will|
|Castleberry, Bobbie - Lana|
|CASEY, KENNETH - Texas A&M Agrilife|
Submitted to: Animals
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/18/2022
Publication Date: 10/21/2022
Citation: Min, B., Willis, W.M., Castleberry, B., Casey, K., Waldrip, H., Parker, D.B. 2022. Condensed and hydrolyzable tannins for reducing methane and nitrous oxide emissions in dairy manure – a laboratory incubation study. Animals. 12(20). Article 2876. https://doi.org/10.3390/ani12202876.
Interpretive Summary: Agriculture contributes to the world-wide production of greenhouse gases (GHG), including methane (CH4) and nitrous oxide (N2O). Plant tannins have shown promise in reducing GHGs from various agricultural activities; however, data are lacking on the effects of plant tannins on CH4 and N2O emissions from dairy cattle manure. Therefore, scientists from USDA-ARS at Bushland, TX and Texas A & M AgriLife Research analyzed the effects of the addition of tannins to manure at two different dose levels (4, and 8%) on GHG emissions. Results indicated that one type of treatment (condensed tannins, CT) applied directly to the dairy cattle manure reduced CH4 emission by over 50% and cumulative N2O emissions by over 40%. Based on these ‘proof-of-the concept’ results from a 14 day lab-scale trial, CT appear to be a promising method to reduce GHG emissions from composted dairy cattle manure. Further research is needed to determine long term effects of CT treatment and the feasibility of scaled up CT application to dairy cattle manure at dry lots typical of the Southern High Plains.
Technical Abstract: The objectives of this study were to (1) examine the effects of plant condensed (CT) and hydrolyzable tannin (HT) extracts on CH4 and N2O emissions; (2) identify the reactions responsible for manure-derived GHG emissions, and (3) examine accompanying microbial community changes in fresh dairy manure. Five treatments were applied in triplicate to the freshly collected dairy manure, including 4% CT, 8% CT, 4% HT, 8% HT (V/V), and control (no tannin addition). Fresh dairy manure was placed into 710 mL glass incubation chambers. In vitro composted dairy manure samples were collected at 0, 24, 48, and 336 h after the start of incubation. Fluxes of N2O and CH4 were measured for 5-min/h for 14 d at a constant ambient incubation temperature of 39 °C. The addition of quebracho CT significantly decreased the CH4 flux rates compared to the tannin-free controls (215.9 mg/m2/h), with peaks of 75.6 and 89.6 mg/m2/h for 4 and 8% CT inclusion rates, respectively. Furthermore, CT significantly reduced cumulative CH4 emission by 68.2 and 57.3% at 4 and 8% CT addition, respectively. The HT treatments failed to affect CH4 reduction. However, both CT and HT reduced (p < 0.001) cumulative and flux rates of N2O emissions. The decrease in CH4 flux with CT was associated with a reduction in the abundance of Bacteroidetes and Proteobacteria.