Soil greenhouse gas flux and nitrogen mineralization following manure application from tannin‐fed dairy cows

Abstract

Growing concerns about environmental impacts of dairy farms have driven producers to address greenhouse gas (GHG) emissions and nitrogen (N) losses from soil following land application of dairy manure. Tannin dietary additives have proved to be a successful intervention for mitigating GHG and ammonia (NH3) emissions at the barn scale. However, it is unknown how land application of dairy manure from cows fed tannin diets affects crop–soil nitrogen dynamics and soil GHG flux. To test this, cows were fed diets at three levels of tannins (0.0%, 0.4%, and 1.8% of dry matter intake) and their manure was field applied at two N rates (240 and 360 kg N ha−1). Soil NH4+‐N, NO3−‐N, corn silage yield, and soil GHG flux were then measured over a full growing season. Soils amended with tannin manure had lower initial NH4+‐N concentrations and lower total mineral N (NH4+‐N + NO3−‐N) concentrations 19 days after application, compared to soils amended with no tannin manures. Despite lower early season N availability in tannin‐fertilized plots, there were no differences in corn silage yield. No differences in soil GHG and NH3 emissions were observed between manure‐amended treatments. These results demonstrate that while tannin addition to dairy cow feed does not offer short‐term GHG or NH3 emissions reductions after field manure application, it can promote slower soil N mineralization that may reduce reactive N loss after initial application.

Green Development of Natural Fibre-Based Paper Mulch from Recyclable Cow Dung and Flax Straw Waste

“…A sharp increase in cow breeding bases with the rapid development of the animal husbandry industry has generated a large amount of cow dung. The accumulation of cow dung generates greenhouse and foul gases, seriously affecting air quality [14], and it is also a source of groundwater pollution, disrupting the ecological balance [15][16][17]. Among them, methane, as one of the main sources of greenhouse gas, is produced through the open-air fermentation of cow dung.…”