Ammonia and Nitrous Oxide Emissions from Dairy Cows on Straw-Based Litter Systems

Abstract

Increasing concerns regarding environmental impacts of animal production require a better understanding of the factors that influence nitrogen (N) excretion by animals and the processes that influence N volatilization into ammonia (NH3) and nitrous oxide (N2O) from manure. The objective of this study was to evaluate the influence of diet characteristics and climatic factors on manure composition, as well as the resulting NH3 and N2O emissions in the barn and during storage of a straw-based litter system. Two groups of three dairy cows were housed in mechanically ventilated rooms and fed with a grass-based diet (GD) or a total mixed diet (MD). The resulting solid manures were stored in ventilated tunnels. The experiment was conducted in autumn (AUT) and spring (SPR). NH3 and N2O emissions were recorded continuously (28 days in the barn, 85 days for storage). NH3–N emissions in the barn were higher for GD-AUT than for MD-AUT, which was consistent with the larger and unbalanced amount of crude and degradable protein in GD, and corroborated by higher milk urea N contents. More than 80% of the NH3–N volatilization occurred during the first week of manure storage, when the temperature of the manure heap peaked. N2O–N emissions were negligible in the barn. During storage, N2O–N emissions peaked immediately after the first week. Higher N2O–N emissions were related to higher rainfall, which may have increased the moisture content and decreased the temperature of the manure heap, thus generating the conditions necessary for nitrification and denitrification processes.

Assessment of Ammonia Emissions and Greenhouse Gases in Dairy Cattle Facilities: A Bibliometric Analysis

“…N 2 O is a byproduct of enteric fermentation and is one of the responsible for the deposition of nitrogen in the ecosystem [ 55 ]. According to Amon et al [ 6 ], the estimates of N 2 O emissions from manure management are based on the assumption that a certain percentage of nitrogen excreted by domestic livestock is released as N 2 O during manure storage.…”

“…According to Amon et al [ 6 ], the estimates of N 2 O emissions from manure management are based on the assumption that a certain percentage of nitrogen excreted by domestic livestock is released as N 2 O during manure storage. There are many uncertainties regarding the factors that can influence the emission of this gas, but it is known that N 2 O emissions during storage vary based on the nitrogen and carbon levels in manure, the accumulation time, the treatment method employed, frequency and amount of substrate added to the bedding, animal type, and feeding system [ 55 , 56 ]. N 2 O stands as a potent GHG, with its emission in the ecosystem raising significant concerns due to its longevity as an atmospheric trace gas [ 57 ].…”

Analysis of the Energy and Material Use of Manure as a Fertilizer or Substrate for Biogas Production during the Energy Crisis

“…Improper and/or long-term storage of manure, as well as its direct application to fields, can cause significant negative economic, ecological and even social effects [6,10,30,34]. One of the most effective methods of reducing the above-mentioned negative effects is the processing of manure by anaerobic digestion (and then using the digestate as a valuable fertilizer) [6,10,27,32,[35][36][37][38][39]. Methane fermentation, and, most of all, the need for a very short storage time, enables the reduction of GHG emissions related to manure management by several dozen percent [2,6,27,36].…”